The EAAP Series is published under the direction of Siem Korver andJea n Boyazoglu

International Symposium organized byth eAnima l Husbandry Institute ofth e University of Tuscia with the patronage of:

International associations: - Food and Agriculture Organization of the United Nations - FAO - International Centre for Advanced Mediterranean Agronomic Studies - ICAMAS - European Association for Animal Production - EAAP

Corporations and national associations: - Ministero Agricoltura e Foreste - MAF - Scientific Association for Animal Production - ASPA - Italian Livestock Breeders' Association - AIA - National Association for Holstein Breeders - ANAFI

Chairmanship of Symposium: Prof. Gian Tommaso Scarascia Mugnozza, Dean of University of Tuscia

Organizing Committee: Prof. Alessandro Finzi, University of Tuscia (Chairman) Prof. Alessandro Nardone, University of Tuscia Prof. Giuseppe Bertoni, Catholic University of Piacenza Prof. Jean G. Boyazoglu, EAAP Prof. Bruno Ronchi, University of Tuscia (Secretary)

Scientific and Administrative Secretariat: The Director, Animal Husbandry Institute - Faculty of Agriculture, Via S. Camillo De Lellis, 01100 VITERBO, Telefax (0761) 257434

Technical Collaboration: Viterbo Livestock Breeders' Association Animal husbandry in warm climates

Proceedings of the International Symposium on Animal Husbandry in Warm Climates, Viterbo, Italy, 25-27 October 1990 (EAAP Publication No. 55, 1991)

B. Ronchi, A. Nardone & J.G. Boyazoglu (Compilers)

Pudoc Wageningen 1991 High environmental temperature which remains stable for any given amount of time may ill-effect animal breeding by upsettingsom e of the endocrine andmetaboli c functions involved inthermoregula ­ tion. Consequently sucha neffec t weakensth e productive performance ofth e animalgeneti c potential. Inarea swher e animal production needst o be increased, it would be necessary to develop research strategies and husbandry techniques capable of limiting the negative effects of hightemperatures . This Symposium aimed at focusing on the biological, technological and productive aspects, tracing thembac kt o acommo nmatri x withth e purpose of identifying researchapproache scapabl eo fdevisin g new production patterns.

CIP-data Koninklijke Bibliotheek, Den Haag

ISBN90-220-1050- 3 NUGI 835

© Centre for Agricultural Publishing and Documentation (Pudoc), Wageningen, Netherlands, 1991.

All rights reserved. Nothing from this publication may be reproduced,store d in acomputerize d system or published in any form or in any manner, including electronic, mechanical, reprographic or photographic, without prior written permissionfro mth e publisher,Pudoc ,P.O . Box 4,670 0A A Wageningen,Netherlands .

The individual contributions in this publication andan y liabilities arising from them remain the responsibility of the authors.

Insofara s photocopies from this publicationar epermitte d byth e Copyright Act 1912, Article 16Ban dRoya l Netherlands Decreeo f 20Jun e 1974(Staatsbla d 351) asamende d in Royal Netherlands Decree of 23Augus t 1985 (Staatsblad47 1) an db y Copyright Act 1912,Articl e 17,th e legally defined copyright feefo r anycopie s should betransferre d to the Stichting Reprorecht (P.O. Box 882, 1180A W Amstelveen, Netherlands). For reproduction of parts of this publication incompilation s sucha s anthologies or readers (Copyright Act 1912, Article 16), permission must be obtained from the publisher.

Printed inth e Netherlands. CONTENTS

Opening session Chairman: Prof.G. T. Scarascia Mugnozza

Opening lecture - G.T. Scarascia Mugnozza ix

Statements: FAO - E.P. Cunningham x ICAMAS - R. Février xi EAAP - A. Nardone xiii ASPA - D. Matassino xv AIA/ANAFI - G. Lanari xvi Introduction A. Nardone xvii

Session1 Chairman: Prof. J.G. Boyazoglu

Endocrinological and neurological systems in body thermoregulation - M.M. Shafie 1

Metabolic responses of farm animals to high temperature - A.J.F. Webster 15

Reproductive responses under high temperature conditions - A. Berman 23

Productive responses of ruminants under high temperature conditions - P. Berbigier 31

Session 2 Chairman: Prof. A. Finzi

Breeding programmes for improved dairy production in tropical climates - E.P. Cunningham 39

Problems associated with the transfer of genetic material from temperate to warm Mediterranean regions: consequences on the equilibration of the animal production systems - J.C. Flamant 48

Selection and breeding strategies for production in warm climates - K.J. Peters 55 Session3 Chairman:Prof. M.M. Shafie

Feeding strategy for animal production in warm climates - J.L. Tisserand 64

Ruminant production strategies in warm climates, a case study: the Iberic Peninsula - A. Vaz Portugal 73

Alternative breeding programs for dairy cattle in North Africa - A. Eddebbarh 81

Session 4 and S Chairman: Prof.G. Trimarchi

The effects of environmental factors on water balance in animals - F. Valfrè, V.M. Moretti & G.L. Maggi 89

Effect of high temperature on production and quality of milk - V. Cappa, L. Calamari,P. Vazhapilly & E. Frazzi 93

Heat stress effects on some blood parameters of sheep - G. Bertoni, U. Bernabucci& G. FilippiBalestra 98

Effects of high temperatures on reproduction in small ruminants - S. Casu, P. Cappai& S. Naitana 103

Italian beef breeds in warm climates - M. Lucifero &A. Giorgetti 112

Session 6

Chairman:Prof. E. Belliti

Breeding strategies in dry-hot countries - D. Cianci 120

Strategies for the use of agricultural by-products as ruminant feed in warm climates - F. Polidori & G. Savoini 126 Suitable engineering strategies for livestock shelters in warm climates - A. Gusman &A. Candura 130 Session 7 Chairman: Prof.G. Rognoni

Preservation of animal ecotypes bred in the Mediterranean area - D. Matassino& F. Grasso 137

Concluding remarks E.P. Cunningham 143

Poster session Chairman: Prof. A.M. Pilla

Rectal temperature and pulse rate of Friesian and Modicana cows in Sicily - P. Giaccone,A. Bonanno & B. Portolano 145

Bioclimatic parameters and hematic profile in Massese ewes reared in Tuscany -A. Martini, P. Lupi, M.P. Ponzetta &A. Giorgetti 146

Factors affecting reproduction on the one-humped camels. Improve­ ments of reproductive performances - P. Minoia, G.M. Lacalandra & M. Moslah 147

Rabbit breeding in hot climates: the underground cell system - P. Morera & G. Kuzminsky 148

Effect of solar radiation on water and food intake and weight gain in "Sarda" and "Comisana" female lambs - A. Nardone, B. Ronchi & A. Valentini 149

Variability of chemical composition and nutritive value of some natural fodders in the valley of river Beles (Ethiopia) - 5.Pastorelli, M. Orlandi, L. Goio, E. Meregalli,G.B. Liponi, F. Taccini & R. Ranzani 151 OPENING SESSION

Among the various types of productive activity, agriculture is the closest to human needs. Although in developed countries productivity is now so high that there are surpluses of provisions, and pollution and quality have become more important problems, in a large part of the World the problem remains the quantitative aspects of production. Both in animal and plant production, it is true that once agriculture becomes capable of producing in excess of human needs, there is the possibility of integrating animal and plant production. So far it has proved impossible to change from pastoral activity to localized intensive stock raising, and every attempt to do so will fail because concentrates have to be imported from another area where they areproduce d in surplus. In hot climates where conditions are governed by a hot environment for more or less long periods, animal production has been hampered either by the major difficulty of maintaining thermal homeostasis, or through lack of the amounts of concentrates necessary to sustain intensive animal production at therequire d level. ' Study of environmental effects is directed principally at aspects linked to production, particularly possible influences on endocrinology, thermoregulation, physiology of production, and thephysiolog y of digestion, milkproductio n and growth; also the genetic resources for use in conjunction with a sustainable husbandry technology. Such study is of fundamental value. However, this knowledge must not be treated in isolation and considered separately. When one is devising feasible production systems, all these aspects have to be taken into account, and all possible interactions have to be considered in order to achieve the best balance in each situation. As a result, meetings on a subject like animal production in hot climates are important, because they offer the opportunity to bring together expertise and different lines of research in the common denominator of the environmental conditions which characterize a large part of theWorld , namely the tropical and subtropical zones. However, whichever series of experimental conditions are taken into account, it is impossible to reproduce the variable phenomena which occur in practice, bearing in mind the infinite possible combinations of elements and their variability in intensity and duration. It is also necessary to consider that the consequences of a particular environmental situation may not become obvious until much later, together with other, different situations which are also involved, to form a complexity of interference, the results of which cannot be predicted accurately. The complexity of problems means that progress can be achieved only through a long series of meetings on the same subject, and incorporation of the advances in the long road of progress in animal husbandry for that large part of humanity which lives under unfavourable environmental conditions. Prof. Gian Tommaso Scarascia Mugnozza Dean of University of Tuscia

IX F.A.Q STATEMENT

Theworl d population isno wsi xbillio n people, seventy percent of whom livei nth e tropical belt which we call the developing countries. A generation from now, ninety percent of humanity will livei n this belt andthei r food requirements will depend totally on local production. The technical topics addressed here are relevant therefore not just for today's world, but areo f critical importance for the future. The animal production industry in the developing countries accounts for about a quarter of agricultural output in strictly economic terms. In a recent study, however, a number of economists and sociologists attempeted to calculate thevalu e of generally "unquantifiable" benefits of the livestock sector indevelopin g countries, for example thewor k function ofbuffaloe s andcattle . The conclusion is that the livestock sector in developing countries accounts for forty-four percent of thevalu e of total output from theagricultura l sector. Atth e same time, these countries are generally improving their living standards, and the livestock sector tends togai n importance asdeman d forit sproduct s increases. The work we are attempting to undertake, therefore, is highly important and as a representative of FAO, I am very conscious of thenee d notjus t for more research but also for exchange of information. I would therefore like to take this opportunity to congratulate the University of Viterbo, and in particular Prof. Nardone, for their initiative inorganizin g this important Symposium.

Prof. E.P. Cunningham Director Animal Production andHealt h Division F.A.O. ICAMAS STATEMENT The subject which will be discussed during this seminar is rather important because concerns a basic aspect of the development of the livestock industry in warm countries. The genetic aspect was the topic of a seminar which was held last November in Tunis. However, even if this problem is rather important, it can be considered a particular case of a more generalproblem , of which I will try briefly to examine. Agronomists of industrialized countries are generally facing temperate or atlantic climate, have progressively adjusted techniques that today are able to enhance the productivity per nectar for plants and per animal for thelivestoc k industry. In particular, animal selection has given the opportunity to have very productive animals with such fanning conditions, characterized by the temperature, humidity and light intensity and also by feed supply, of thetemperatur e regions. We are strongly attracted by theresult s obtained on meat productions, milk and egg output from the different animal species raised in these conditions, we are, actually, tempted to reproduce the sameresult s of other regions. The sameoccur s for plant production. This tendency to imitate those high productive technologies, it might bring to use the same animal or plant material in order to reproduce the same conditions in which it was selected or raised with success. We do also see irrigation as a way to have green atlantic landscape, but only on limited spots of dry regions. We might also face florishing fodder crops used to feed demanding animals, that we should also protect from high temperatures and from light intensity which are difficult to adapt to them. In reproducing the environmental conditions we might reach also the sameproductivity . At what price? Animals are mostly imported. During the seminar on milk policies in the Mediterranean held at Rabat, a maroccan expert estimated at 4.000 $ the cost for an Holstein cow imported and raised in that country. It is necessary to feed them according to their needs, which are substantial in quantity and in quality, also the cost of irrigated fodders is very high especially if compared to an eventual shifting in those areas to food crops (fruits and vegetables). Importing feed is a way to loose strong currency. Breeding and the equipment get usually more expensive going South. Air conditioning is a real progress, if we do want "make money" with animal production, or do, we want an animal production spending money? The question of labor. Workers should be very specialized in order to take care for these animals and technologies and often they are not always available. Any how, there is also the adjustment of salaries to higher levels. The list of things just mentioned, and on purpose in a negative way, should demonstrate that the transfer of animals and technologies from temperate countries to warm countries raises several problems and it is not a satisfactory solution. We might ask us the question if we should not do in warm countries, often dry, what hasbee n done, with favourable results, in temperate countries, in the sense of: - try to adjust techniques in order to use in a modern way the possibilities offered by local fodder systems; - operate an animal selection which will privilege characters suitable for local conditions concerning temperature and feeding systems. On my opinion, this is the most practical way, even if it is hard, if requires an original effort or it might seem less "modern" to the eyes of whom is delighted to seei n Africa the reproduction of a livestock industry similar to the dutch one. This criterium needs a deep research of our knowledge vis-à-vis of the principal animal factors such as: milking, nutrition, reproduction. If we will reach a better understanding of the role of these factors, we might hope to have available rational bases to develop the place of the livestock industry in warm countries. This research pattern might seem hard and long, but it isprobabl y theonl y one that does not give any xi inconveniences. Is this an impossible challenge? Agronomist of "cold" countries have learned how to win the winter, water flooting, to exploite non fertile land after centuries of challenges and thanks to a strong scientific effort. How come agronomists from the South have not reached thepoin t matwoul d allow them to control the heat and dryness? Is the South affected by an ecological malediction? Is it merely affected by a technological gap? We saw mis progress on plant breeding, where Europe has learned in the past centuries how to crop certain plants originating from tropical areas, without changing the climate, but creating instead adaptable varieties and also adapting technologies to the european conditions; com is originating from Mexico, tomatoes from Central America, wheat from the Middle East. There was not a transfer, but only a long work to "domesticate" those speciest o our temperate conditions. In order to realize this long and patient multi-subject work, researchers of warm countries will be facing the problem to deeply investigate and learn the foundamentals of biology following a pattern which has never before perspected by northern researchers. However, at the same time their precious work would serve their country and also the international scientific community, favouring exchanges of information. This will be a real cooperation without being dominated or dominating. I am very confident that this is going tob e the mainstream of this seminar. Dr. Raymond Février Secretary general of ICAMAS

Xll EAAPSTATEMENT In the context of animal production, "heat" refers to the climatic conditions of the environment, and to the upper limit of thermal neutrality. Within a species, this limit varies with genetic type. Climatic factors generally considered to be important in livestock rearing are temperature, humidity, solar radiation, ventilation and precipitation. The effect of each climatic factor isvariabl e in relation to its intensity and interactions with other factors. For the purposes of rearing it is important to distinguish between hot, dry and hot, moist climate for their direct and indirect effects on animals, among them the availability of nutrients, risk of infection with pathogens, also socio-economic and technico-cultural organization. Above all, the possibilities for heat exchange between the animal and its environment are decisive when rearing takes place in a hot environment. Body temperature and skin temperature are fundamental criteria for many investigations. Skin temperature is related to die thermal conductivity of skin tissues, the circulating volume of blood and peripheral vasodilation or vasoconstriction, whereas skin pigmentation and colour of the hair coat are important for the purpose of reflecting and absorbing solar rays, particularly a protective function in relation to wavelength of therays . In more general terms, the complex processes of thermoregulation available to an animal become important in a hot climate. These processes involve heat exchange (conductivity, sweating, respiration, etc.) and those which reduce heat production (metabolism, intake of feed and water). Awareness and a better understanding of these processes are important for appropriate husbandry methods (feeding, management, shelter, health precautions, etc.) topermi t the animal to achieve optimum reproduction functions and productivity. From the aspect of genetic improvement, although there are widely held opinions that the productivity of animals can be improved better and more quickly by paying attention to environmental components (particularly feeding) rather than genetic factors, are there not margins within which genetic improvement can influence specifically animal populations reared in a hot climate? Numerous examples indicate that genetic selection in a temperate climate does not diminish their reproductive and productive potential in a hot climate, but the interactive effect between genotype and environment does not invariably validate such results. Variability in phenotypic expression results from a complex state of dynamic equilibrium, which can be accentuated or suppressed in different environments, whether for production or reproduction. The origin of this phenotypic variability (both nongenetic and genetic) influences the type and method of possibilities for improvement. Consequently it is important to interpret correctly the "response" and/or the origin of the phenotypic variation. In the case of hot environments, as in other environments, it is important to bear in mind that thephysica l environment cannot vary, but management technique can. The purpose of these brief comments is to stimulate the study of animal production in hot climates within this vast field of research, and particularly to consider the possibility of establishing improvements in husbandry techniques for thosevas t areas of plains where the human diet is deficient in animal protein. In principle, an area may be considered hot if the mean annual temperature exceeds 20°C, and such a condition prevails injus t under 50% of a territory populated by about 2.3 billion persons. This zone has 600 million cattle (about half of the World population), 80% of buffaloes, 40% of sheep and 60% of goats, without mentioning species of lesser importance. Turning to individual continents, theproportio n of livestock rearing in a hot climate is just as high when zones of continental climate having long periods of temperatures around 20 °C are excluded. Thus in Africa, about 70% of the cattle, sheep and goats are in the hot area, and they supply food and to some extent work for about 80% of the human population of the continent. Also in Asia and central and south America they

Xlll rear some70 % of their cattle in theregion s hot area. Generally the productivity of this entire animal population is modes, and its contribution to the supply of protein in thehuma n diet is limited. In 18 countries of the hot area, daily consumption of animal protein per inhabitant is under 10g, while in another 66 countries it is under 30g. Enhancement of productivity of the animal populations of such areas would contribute to correcting the socio-economic imbalance, and would contain the intensification of production (which hasbecom e controversial) in temperate areas. This state of affairs seems to me to underline the importance of discussing a subject like "Rearing animals in hot climate". Among other things, the theory of a "greenhouse effects" has created a new aspect of interest in this problem. I would like to mention that such interest is reflected in research being conducted at the Zootechny Institute of Viterbo University, initially on rabbits, and morerecentl y on sheep and cattle. This Symposium will be an occasion for sharing opinions and experience in profitable debate in order to stimulate new research in this field. In fact, while research has made important advances, there is still ample scope for studies and improved knowledge. Prof. A. Nardone President of EAAP

xxv ASPA STATEMENT

It gives me great pleasure to welcome the Scientific Association for Animal Production, which I have the honour to represent, to this interesting Symposium organized by our animal husbandry colleagues on the occasion of the ten-year anniversary celebrations of theUniversit y of Tuscia. The Association is particularly aware of theproblem s to be confronted during this Symposium. In fact, there is within the Association a study group whose task is to examine the animal husbandry problems of tropical and subtropical agriculture. I am certain that the result of this scientific meeting will contribute to solutions of these complex problems of animal production in hot climates, as hasbee n stressed by Prof. Cunningham, which includea largepar t ofItaly . Whithin 20year s ourplane t will beinhabite d by7. 2 billion persons, compared with just over 2 billion today, andi t will have toproduc e about 28 million tono f protein of animal origin. This will create major problems for animal husbandry. Moreover, the solution to these problems rests with animal production in tropical and subtropical areas, where there hasals o been a major increasei n the population. In this spirit, I wish themeetin g every successi n theprestigiou s surroundings of the University of Tuscia.

Prof. D. Matassino President of ASPA

xv AIA/ANAFI STATEMENT

It is with great pleasure that I convey to you the greetings of the Italian Breeders Association, of the National Association of Italian Friesian Breeders and of the Provincial Breeders Association of Viterbo which I have the honour to represent in this occasion. The subject of this meeting is undoubtedly of considerable interest for the italian breeders world which is, since a few years ago, projecting itself outside its traditional borders. This is particularly true with the mediterranean countries as evidenced by the exchange of technology and genetic material which is taking place. I would also like to enphasize the fact that our associations are intensifying relations with the italian scientific world. In fact, our work could not easily be carried out if our study and research offices were not supported, for certain subjects, by research carried out by other institutions. In this status of cooperation results and conclusions reached at this meeting will by us be kept in maximum consideration and may result of utmost importance to the continuous improvement of our sélection technology. Such technologies must now be fixed and carried on keeping into account the international context in which animal breeding takes place. For Italy, this context is represented by Europe but mainly by the mediterranean basin countries. Thank you and let me renew my warmest welcome.

Ing. Giancarlo Lanari AIA/ANAFI

xvi INTRODUCTION

Considered as a whole, the animal production system is one of the most complex, because of the numerous factors involved in the production process and the wide variations in types of husbandry. In the temperate zones of theplanet , particularly in the Western part of the Nothern hemisphere, die past decade has seen the development of increasingly intensive husbandry systems. These operate under more or less favourable conditions adapted to the factors involved in the production process. In particular, the type of soil, climate and water resources have generally favoured a satisfactory supply of feed. The availability of feed and the climatic conditions are important to achieve the types of animals with the physiological characteristics required for high individual productivity. Such favourable conditions have enhanced the socio-economic situation in many societies, and it is industrial development which has increased the demand for animal products. In order to satisfy this increased demand for animal protein, science and technology is faced with challenges requiring speedy solutions. There can be no doubt that studies in physiology, genetic, nutrition and feeding haveprovide d the fundamental instruments for development and intensification of livestock rearing. Often this has led to the selection of animals best adapted to a given environment, rather than adapting the environment to the animal. The commonest examples of this are poultry and pigs, and to some extent cattle. Today we are attempting to understand the various physiological process in order to meet the requirements of animals and to adapt the technical environment of the farm, the selection of animals for desired aims by genetic improvement and manipulation of the genome. How much of this scientific and technical knowledge can be applied to the development of livestock farming in high temperatures? How can it contribute to increased animal production in hot areas? What should be the new lines of specific research in the unfortunate eventually of new areas of the World developing higher temperatures as a consequence of the "greenhouse effect"? All these problems, which will receive an airing at this Viterbo conference, are problems in which the European Association for Animal Production (EAAP) is heavily involved by statutes, tradition and actual activities. The seven study commissions of EAAP examine research into the breeding of the principal species of animals of agricultural interest. In particular the three commissions which deal with genetics, nutrition, and management and health are concerned with a wide range of species reared in member countries, from reindeer to camels. In fact, the 30 member countries of EAAP extend over a territory from the 70° parallel in the North to the Tropic of Cancer in the South, with a transition from the Artie Circle (USSR) to the tropics (Egypt). Moreover.in recent years EAAP has started to tackle in more organic and specific way the problems of rearing animals in a hot climate by forming two Working Groups ("Tropics and subtropics", "Systems of Bovidae production in the Mediterranean"), and has organized major studies of specific research and Symposia, in collaboration with ICAMAS, held in capitals of North African members of EAAP (Cairo 1988, Tunis 1989, Rabat 1990). As a consequence the reasons which EAAP has tob e involved with this Symposium are evident. Prof. A. Nardone University of Tuscia

xvii Endocrinological and neurological systems inbod y thermoregulation

M.M. Shafie Department ofAnima l Production,Facult y ofAgriculture , CairoUniversity ,Egypt .

Abstract This review articlepresent s thearea s of recent approaches andconcept s inth e field of biological thermoregulation withparticula r reference toth e hypothalamus asth emaste r organ.Th ementione d areas are (1)Simulatio n models of automation (biological cybernetics). (2)Mathematica l assessments of heat flow through input and outputpath s and feedback signals. (3) Theconcep t thatheterotherm y ismor e efficient adaptation toenvironmenta l thermal condition thanhomeothermy. ,(4 ) Complementary adaptive coincident control ofphysico - chemical properties -temperature ,osmosi s (water/ions) and acid-base balance (pH).(5 )Th eexpecte d significance ofth econtributio n of therume n inth ebalanc e ofbod y physico-chemical conditions. (6)Th eparticipatio n ofth e hypothalamus incombinin g behavioural and autonomic activities of thermoregulation. The alignment of hormones acting in thermoregulation and complementary physico-chemical control is show- diagrammatically -i naccordanc e with the biological cybernetic pattern.Thi spatter n isth ecompoun d -comple x -makeu p of:senso r (stimuli receptors) input,th e effectors (physiological functions)outpu t and the feedback controls at stratified levels. Recent approaches and concepts Parallel toth erapi d developments intheorie s and achievements inphysica l automation and cybernetics the physiologists suggested simulation models forth e mechanism of theneura l and endocrine systems as cybernetics components.O f course thesemodel s arebase d onresearc h work and findings of structure and functiono f these systems and theiroutcome s insystemati c functions. Thermoregulation seems tob e anic e field for such approaches.W ehav e tob e aware,however ,tha tan y simulationmode l foran y living function isa matte ro f abstraction of the intricate interactions with other functions,actuall y the animal asa whole .Henc e the models have tob edevelope d from simple tocompoun d ones. Thermoregulation of alivin g organism isa mus twhic h involves all thebod y systems,cell s or evenmolecule s and ions.Throug h the lifeo f the animal there are spontaneous reactions and continuous train of events struggling tokee p the internal body temperature within adurabl e range maintaining its life.Thi s range is,however , determined by the thermodynamic properties of thematter s of the animal body and ambient environment. The environmental thermal conditions and fluctuations- seasonally and diurnally -impos e at any moment two directional paths of heat, input and output into and/or from the animal body. The animal had toreac t to this apparently mess of environmental events in order to retain its normal vital body temperature.O f course this reaction will bemor e elaborate, tedious and involving more physical setups and physiological functions whenever the environmental thermal conditions are severe, cold or hotan d fluctuations arewid e and /or rapid. Both environmental thermal actions and the animal counteractions occur inaccordanc e with physical lawso f thermal interchange at the interface of the animal surface. This calls forth relevant bioenergetics systemic functions inside the animal's body.Thu s the living setup isalway so n the alertb y automatic control mechanism fulfilling the optimal balance between thermolysis .(heatlos s or dissipation) and thermogenesis (heatproduction) . This ever changing control could be simulated toa simplified extent by cybernetic models comprising: sensor/s (measuring inputs), regulator (fixing set-point reference) corrector/s (adjusting relevant output) and feedback signals. The simplest cybernetic simulation model of thermoregula­ tion implies : (1)Sensors,hea t sensing elements; external in skin and mucous membrane of thebucca l cavity (Bligh, 1985)assessin g ambient temperature and internal in spinal cord and hypothalamus (Hensel, 1973)assessin g internal tissue and blood temperature, (2)regulator , (the hypothalamus)dictatin g set-point reference temperature, (3)Correctors , (theneura l and endocrine systems and (4) effectors thephysiologica l function) for input and/or output ofheat . Bligh (1985)presente d athoroug h discussion of a cyberentic model of thermoregulation based on review of experimentation and deductions from neural functions. He emphasized involvement of two neural populations warm-sensorsan d cold-sensors both stimulated conversely around a set-range of temperature.Th eproportion s of these two populations varywit h site,Ski no r core and itma y vary among species. Bligh, also,forwarde d arecen t and logic concepto f heterothermy adaptation, this is the labile change ofbod y temperature -withi n particular range -i n face of changes in environmental temperature.Thi s ability ismor e beneficial for thewelfar e of theanima l than the traditional concept of homeothermy.A s Ia m noting later heterothermy is the only means thatwor k in the general homeostasis of the animal core physico-chemical conditions : temperature, osmosis,p H and hydrostatic pressure.Thi s Bligh's cybernetic model is nicely built ondeduction s from neural synaptic arrangements with converging excitatory and inhibitory influences.Figur e 1show s thediagraraati c presentation of these concepts asdraw n by Bligh (1985). Riggs (1970)discusse d thermoregulation through comprehensive mathematical models and equations of heat flow paths. His study, however, isbase d onparameter s and assumptions foradul thuman . Ifee l itwil l be interesting to try such approach for livestock species in different productive status. The above discussions are pertaining with thermoregulation per seagains t heat stress.Howeve r in the hot aridareas , i.e. subtropics.Animal s are confronted with combined heat stress and drought.Th e need of surpluswate r evaporation forhea tdissipatio n will disturbwate r and mineral components in the body compartments particularly vascular and extracellular compartmentswhic h isa trouble with water shortage. Such disturbances will necessitate work for osmotic balance and maintenance of hydrostatic pressure (particularly blood pressure). The hypothalamus achieves thiswor k alongside heatregulatio n in an integrated complex of neuro-hormonal cybernetic arrangement. The hypothalamus harbors Osmoreceptors (sensors of change in osmotic pressure) (Verney, 1947an d Durham &Novin , 1970). On the other hand the participation of the hypothalamus in control of blood pressure ismediate d by pressoreceptors (sensorso f hydrostatic pressure with changes inbloo d volume and pressure) inaorti c arch and carotid sinus.Accordin g to messages from these two types of sensors the hypothalamus adjust the functions of the effectors (physiological systems) through neural and endocrine systems. Baxton (1986)state d that the interaction between these two types of receptors suggests that the stimuli affecting them are integrated in thehypothalamus . An additional burden on the hypothalamus incorporated with thermoregulation is encountered innon-sweatin g animals and toa specific extent inanimal swit h less active sweat glands. In these animals panting is themajo r avenue of water evaporation needed forhea tdissipatio n and thermoregulation. In sucha case hyperventilation may enhance output of COa from thebod y thus upsetting the acid-base balance inbloo d which disturbs the vital set-point of pH in thebody . Thompson (1985)referre d to Hales (1981)assumin g thathea treceptor s in the hypothalamus increase respiration frequency while lowPCo z inbloo d acts viamedullar y chemoreceptors (sensors)i n regulation (insuc h case reduction) of respiration depth (tidal volume). In some of our studies,direc t solar radiation heat stress caused severe panting in temperate cattle and sheepbreed s incompariso n to local breeds, the blood plasma bicarbonate store (themajo r acid-base balance buffer)decrease d innativ e Egyptian cattle while it increased in Dairy Shorthorn and crosses (table 1) 'probablydu e to shallower panting in the exogenous breed and crosses (Shafie & Badreldin, 1962). It is clear in the table thatp Hwa s almost stable,howeve rwit h tendency todecreas e Neural Interpretation Convection Resp. Ventilation- & water convergence vaporisation

Effectors, Sweating- J Wat er motivation I vapporiratioi n |Convection Skin, Vasodilation. & Radiation

Heart ôfLung Output rnp>

Feedback 1 Neurohormonal Hormonal, participation Rise of metabolic rate. Hypothalamich . Brown fatmetabolis m (Neonatal) A. Pituitary, tropich . Muscular work T» , T.h . (Shivering) Glucocorticoids

Figure 1.Component s ofthermoregulatio n cybernetic control, adapted from Bligh (1985, Figure12) . (+)activating neuron, (_) inhibiting neuron . in the temperate breed. The stability of pH,generally , isassume d tob e accomplished by mediation of the hypothalamus between the inputo f both heat-,osmo - and chemo-receptors and the effector functions of therespirator y and urinary systems in this concern.Th e co-operations of the functions of these two systems under hotari d conditions needs elaborate well designed experiments withdifferen tspecies' .

3 Table 1.Changes 'i nbicarbonat e store (C02 of HCO -) and pH inbloo d plasma of native (Egyptian)cattle , temperate (Dairy Shorthorn)an d crosses cattledu e to heat stress of direct solar radiation (2hs) (air temp, in shade 35°C).

Breed %chang e Yearly average C0= pH CO2 cm3 pH N. Cattle -7.2 +0.3 51.8±1.4 7.6 D. Shorthorn +4.6 -1.1 49.9*1.6 7.6 Crosses +3.7 0.0 53.4+0.5 7.6

I like todra w theattentio n to the possible significance of the ruminant stomach in this complex of adaptation toho t conditionb y several actions :(1 )absorptio n of alo to f themetaboli c heat input in itsgrea t amount of water intake,wit h the high specific heat ofwater , (2) participation in osmoregulation, (3)th e labile change of intraruminal pH is expected tohel p inmaintainin g normal plasma pH through absorption from the rumenwall . Iti s interesting that heatreceptor s and pH receptors are reported inth e rumen (Webster &Johnson , 1968,an d Leek & Harding, 1975). These receptors have local reflexeffect , howeverWebste r &Johnso n stated local heating of the rumen increases respiration frequency.Weinber g (1976) considered the ruminanta s two subsystems (evena s two suborganisms), thebiomas s of the rumen and themamma l itself. He stated thatbot h parts respond notonl y to the environment but alsoto each other.Recen t studies inou rdepartmen to n responses of buffaloes and sheeprume n to heat stress give evidence on the interaction of the rumen inbod y temperature,osmosi s andp H (Shafie,e t al. 1990)an d (Ashour, et al. 1990). We have toregar d therol e of the hypothalamus in behavioral responses to thermal stress.I n this concern the hypothalamus is connected neurally with the thalamoneocorti- cal apparatus in thebrai n (Nauta, 1963). This CNS arrangement (moredevelope d inmammals ) enables theanima l toforese e hazardous changes inenvironmenta l conditions,a quality called "Long-term anticipation".Accordingl y the animal behaves for self and /o r specieswelfare . Through neuro-hormonal convergence the hypothalamus participate in behavioral responses via somatosensory afferent fibres (sensors of different environmental conditions) and somatomotor efferent fibres aswel l as autonomic efferent fibres to effectors.Ingra m &Daunce y (1985)referre d to Satinoff's (1977) suggestion thatbehaviora l and autonomic thermoregulation are controlled by parallel but anatomically unconnected systemswhic h raises the possibility that imposed thermal stress could influence one appropriate response without affecting another.O f course deliberate behavior response/s will save the animal from disastrous effect of stress and reduce elaboration of physiological functions. Genera, species and breeds vary widely in the pattern of behavioral responses consequently showgrea t differences inphysiologica l reactions.Bot h patterns and their interdependence ought tob e given consideration in judging adaptability toho tconditions .Studie s in responses of local and exogenous sheepbree d in hot reclaimed desert area (inEgypt ) proved clear-cut breed differences in these twopatterns , (Shafie &Sharafeldin , 1965an d Sharafç.ldin& Shafie, 1965).

Neuroendocrine Role of the Hypothalamus The hypothalamus is the site of convergence of stimuli receptors (sensors)o f different physical conditions of external environment and thato f internal body core (temperature, osmosis and pH).Accordingl y the hypothalamus fits out a set-point (reference value) for the condition/s concerned in the body core (temperature for example)an d directs the effectors toachiev e balance between inputan d output of this condition tomaintai n this set-point through feedback signals.Thi s set-point by its turn is liable to displacement -withi n vital limit -primarily due to involvement of nonthermal factors as proposed by Hensel (1973). The hypothalamus executes-these functions through neural and neurohormonal messages to the effector systems. Table 2.Hypothalamic-hypophysea lhormones .

Hypothalamic hormone Acronym Pituitary hormone affected» Corticotropin-releasing CRH ACTH (LPH,MSH ) hormone Thyrotropin-releasing TRH TSH (PRL). hormone Gonadotropin-releasing GnRH(LHRH, LH,FSH. hormone PSRH) Growth hormone-releasing GHRH or GH hormone GRH Growth hormone release- GHRIHo r GH (TSH,FSH, inhibiting hormone; SRIH ACTH). somatostatin;somatotropin release-inhibiting hormone Prolactin release-inhibiting PRIH or PRL hormones. PIH

The hypothalamic hormone hasa secondary or lesser effect on the hormones inparentheses . From Granner,D.K. , (1988,Tabl e 45-1).

Theneuroendocrin e role isachieve d by secretiono f hypothalamic hormones.Vasopressi n (Antidiuretic hormone ADH) and oxytocin are carried by axontransportation toth e posterior pituitary tob e stored there and released as required. On the other hand several hypothalamic hormones (factors)ar e released inth ebloo d stream and carried by humoral transportation toth e anterior pituitary. Some of these hypothalamic hormones are activators while others are inhibitors of the relevant tropic pituitary hormones (Table 2)whic h control theproductio n of ultimate hormones. Humoral feedbacks adjust the concentration levels ofultimate , tropic and hypothalamic hormones by different levels of feedback loops (Figure 2).Figur e (3)show s the neural and humoral convergence in the hormonal makeup.Th e hypothalamic hormones by their turn are adjusted by supervision from theuppe r CNS,obviousl y by neural connections, however some connections may beo f neurosecretory character as suggested by Szentagothai et al. (1968)referrin g to several experimental studies (Figure4) . Thermoregulation involves these levels ofneural , neurohormonal and hormonal participations.Moreover ,a s discussed above,thermoregulatio n (heatexchange ) cannotb e accomplished without incorporation of regulation of osmosis r

External/internal environmental signals

Water balance (vasopressin)

Figure'2. Levels of feedback mechanism adjusting the concentration of hormonal sequences, from Norman Litwack (1987.Figur e 3-1)- Primaryelectrica lo r chemical signalfo r releaseo fR Hfro mCN S(

Interneuronaffectin g RH-producing neuron cell bodyo fRH-producin g inhypothalamu s neuron

Nerve fibres that transmit signals Releasing hormone (RH)

Possible intérneWon affecting RH releasea tnerv eendin g

// Interneuronaffectin g blood flowan davailabilit yo fR H toanterio rpituitar ycel l

•yr— O Neuronswhos esecretion s acto npituitar y cells directly Exocytosiso f anteriorpituitar y hormone

Fenestrate!« capillary IAnterio r pituitary hormone

Figure 3.Collaboratio no f CNS neural signals in hormonal output,adapte d fromNorma n& Litwac k (1987, Figure 3-11). ADRENAL THYROID

Figure 4. Levels (I - V ) of the neural and hormonal release and control of thyroid and adrenal cortex hormones. I, Upper CNS (HB - habinular nuclei, in thalamus), II Hypothalamus nuclei. III Hypothalamus area releasing Hyp.h., IV Pituitary (Hypophys.) releasing tropic, h., V Ultimate release of corticoids h. and Ts & T«, beaded lines denotes neurosecretory mechanism, adapted from Szentagothai et al. (198G, Figure 153).

10 and pH in thé body core.Tabl e (3)present s themajo r hormones concerned with this adaptation complex; and figures (5&6)sho w the feedbacks between the hormonal levels forth e ultimate hormones, and theparticipatio n of other factors if present.

Table 3.Hormona l levels mastering heat production and water/ions balance.

Destined Hormonal level control Hypothalamic Pituitary Ultimate

Heat- TRH TSH T3 &T. » production Water ions GRH ACTH Corticoides Mineralocorticoides (Aldosterone)0 Water reserve ADH ADH ADH (stored) (released)

» Insulin and Glucocorticoids are involved according toth e characters ofmetaboli c pool substrates andpathways . toOthe r agents are involved, Na* &K - concentration and angiotensionII .

References : Ashour, G., Shafie,M.M . &Morad , H.M. 1990.Balanc e of water and Na* &K - concentrations inbod y compartments of buffaloes. (Under Publication). Baxton,Mary , J.W., 1986.Endocrinology , biological and medical perspectives.Wm . C. Brown Publishers,Dubuque , Iowa,USA ,p .271-275 . Bligh, J., 1985.Temperatur e regulation. InM.K . Yousef (Editor) Stress Physiology in livestock, I, Basic principles. CRC Press,Florida ,USA ,p . 75-95. Durham, R.M. &Novin ,D. , 1970.Slo wpotentia l changes due toa n osmotic stimulus inth epreopti c nucleus ofth e rabbit.,Am . Journal,Physiol .21 9 :29 3 -29 8 (Citedb y Baxton,Mary , J.W., 1986,p .273) . Genuth,S.M. , 1983.Th ehypothalamu s and the pituitary gland. In R.M. Berne &M.N .Lev y (Editors) Physiology, C.V. Mosby Co.,St .Louis ,USA ,p .980-983 . Granner,D.L. , 1988.Pituitar y and hypothalamic hormones.I n R.K. Murray, D.K. Granner, P.A. Mayes &V.W . Rodwell (Editors) Harper's Biochemistry. Appleton &Lange , California,USA ,p .482-484 .

11 Thormol Caloric Adrenergic

—^- Stimulate -^-Inhibit

Exogenous *—T4/T, —*-i. hormon«

Stress

Norepinephrine Serotonin

ACTH-

* Stimulai* *— Cortisol 'V»*- Inhibit

Figure 5.Sequence s of release and control of thyroid and adrenal cortex hormones,fro m Berne &Lev y (1983, Figures 52-5& 52-8).

12 SIGNAL decreased blood volume/ decreased (Na-] (macula densa) decreased blood pressure (afferent arteriole) NEP stimulaies renal nerve

kidney juxtaglomerular cell

RENIN

PLASMA ALPHA2 GLOBULIN (57K) ANGIOTENSIN I (decapeptide)

CONVERTING ENZYME Î ANGIOTENSIN II (cctapeptide hormone) (tl/2- 1 mm)

ZONA GLOMERULOSA Feedback Signal

ALDOSTERONE

SENSITIZES SMOOTH MUSCLES Of 3LOOO VESSELS TO NE? KIDNEY MUCOSAL CELL f No* A8SORPTION FROM URINE VASOPRESSIN ON? I -WATER REABSORPTION I - INCREASECT3LOOD PRESSURE I REVERSAL OF ORIGINAL SIGNAL I

Figure 6. Sequences and factors affecting release of aldosterone in relation with water/Na* balance with blood volume and pressure,adapted from Norman -&Litwac k (1987, Figure 15-8).'

13 Hales, J.R.S., 1981.Regulatio n of panting.Advance s in Physiological Sciences,Vol .2 2 (Cited by Thompson,G.E. , 1985, p. 160). Hensel, H., 1973.Neura l process in thermoregulation. Physiological Reviews,USA , 53 :954-958 . Ingram, D.L. &Dauncey , M.J., 1985.Thermoregulator y behavior. InM.K .Youse f (Editor)Stres s Physiology in livestock, I, Basic principles,CR C Press,Florida , USA, p.105-107 . Leek, B.F. &Harding , R.H., 1975. Sensory nervous receptors inruminan t stomach and the reflex control of reticulo-rumenmotility . InMcDonald , I.W..&Warner , A.C.I. (Editors)Digestio n and metabolism inruminants . University of New England Press,Armidale ,Australia . Nauta, J.H., 1963.Centra l nervous organization and the endocrine motor system. InA.V .Nalbando v (Editor) Advances inNeuroendocrinology , University of Illinois Press. Urbana, USA,p . 16-18. Norman,A.W . &Litwack , G., 1987.Hormones ,Academi cPress . London,p . 103, 118& 624 . Riggs, D.S., 1970.Contro l theory and physiological feedback mechanisms.William s andWilkn s Co.,USA , p.383-400 . Satinoff,E. , 1977.Centra l nervous control of thermoregulatory behavior. Proc. Int.Congr .Physiol . Sei. 11, 12.70.1977. (Cited by Ingram, D.L. &Dauncey , M.J., 1985). Shafie,M.M . & Badreldin,A.L . 1962.Th e role of blood in regulating body heat inbovines .J . Anim. Prod., Egyptian Soc. ofAnim . Prod. (Editor),Vol .2 ,p . 61-74. Shafie, M.M. & Sharafeldin,M.A . 1965.Anima l behavior in the sub-tropics. I.Hea ttoleranc e tograzin g behavior in sheep,Netherlands ,J . Agric. Sei., 13,p.-1-5 . Shafie,M.M. , Morad, H.M., El-Baddawy,T . & Salem,M.S . 1990. Response of sheeprume n tohea t stress and roughage level in ration (UnderPublication) . Sharafeldin, M.A. &Shafie ,M.M . 1965.Anima lbehavio r in the sub-tropics. II.Grazin g behavior of sheep. Netherlands, J. Agric.Sei. , 13p .239-247 . Szentagothai, J., Flerko,B. ,Mess ,B .& Halasz ,B. ,1968 . Hypothalamic control of anterior pituitary. Akademi kaido. Budapest, Hungary, p. 198-204 &386 . Thompson, G.E., 1985.Respirator y system. InM.K . Yousef (Editor) Stress Physiology in livestock, I., Basic principles. CRC Press,Florida ,USA ,p .156-160 . Verney,E.B. , 1947.Th eantidiureti c hormone and factors which determine its release.Proc .Roy . Soc, London, 135 : 25-106 (Cited by Baxton,Mary , J.W. 1986,p .272) . Webster,M.E.D . &Johnson ,K.G. , 1968.Som e aspects of body temperature regulation in sheep.J . Agric. Sei. (Cambridge), 71 p.61 . Weinberg, M.S., 1976.Summar y and review of the roleo f buffers in ruminantdigestio n and physiology. InM.S . Weinberg &A.L .Sheffne r (Editors). Buffers in ruminant physiology and metabolism, church &Dwigh t Co.,Maryland , USA,p . 160-169.

14 METABOLIC RESPONSES OF FARM ANIMALS TO HIGH TEMPERATURE

A.J.F.Webster

Department of Animal Husbandry, University ofBristo l School of Veterinary Science,Langfor d House,Langford , Bristol BS18 7DU,U.K .

Summary

The primary problem faced by farm animals inwar m environments isa n inability to dissipate heat from essential thermogenic processes at a rate sufficient tomaintai n homeothermy. Farm animalsma y be classified, on the basis of heat exchanges,i n two groups, (1)pig s and poultry who maintain homeothermy largely by regulating heat production (Hp); (2)ruminant s and horses who rely, inmos t circumstances, on regulation of evaporative heat loss. Prolonged exposure to heat causesa fall inH p attributable toa reduction in food intake and essential,thermogeni c processes of digestion and metabolism. Thermoneutral Hp can be analysed into effects of size,physiologica l state,activit y and heat increment of feeding (HIF). Effects of size onHp/m 2 surface area are small. Effects of physiological state on Hp (kJ/kg"'^5,d)ar e substantial. These can be attributed mainly to differing proportions of the most metabolically active tissues (gut and liver). Metabolic rates per unit mass of a specific organ or tissue are probably unaffected by plane of nutrition. Effects of environmental temperature onH p per unit mass of tissues (other than brown fat)ar e unknown but probably negligible. Adaptation of species and strains towarm , dry environments involves a variety of subtle changes in heat dissipation, water balance, energy and protein metabolism. Metabolic acclimation to heat in the individual involves a reduction in appetite and thermogenesis. It appears that the one can explain the other. There is little evidence for a change in metabolism that could sustain productivity inwar m environments.

Introduction

A farm animal is generally considered to be thermally comfortable or ina state of thermal neutrality when heat produced asa n inevitable consequence of metabolism (thermoneutral Hp)i sdissipate d to the environment by sensible (convection, conduction and radiation)an d "insensible"mean s (evaporation of moisture from the skin and respiratory tract)withou t distress and at negligible metabolic cost (McDowell, 1972; Monteith & Mount, 1974). The primary problem faced by farm animals inwar m environments arises from their inability to dissipate heat from thermogenic processes essential tomaintenanc e and production at a rate sufficient tomaintai n homeothermy. Other effects of heat stress onphysiolog y and performance,e.g . changes in hormone secretion, fertility or milk production, can nearly always be shown to be secondary to the need to reduce metabolic rate. This paper will consider the factors that determine thermogenesis in farm animals,th e extent towhic h they are affected by heat and how these effects may be ameliorated. Exact mechanisms for neural and hormonal control of thermogenesis will not be discussed; I shall simply assume that all are working normally.

15 Heat exchanges in farm animals

Patterns of heat exchange in farm animals are illustrated inFig. 1 (from Webster, 1983a). This figure distinguishes two groups. Group 1, e.g. pigs and poultry,maintai n homeothermy inmos t environments to which they are habitually exposed by regulating Hp to keep body temperature up_t o the desired set point. Group 2,e.g . ruminants and horses,maintai n homeothermy inmos t circumstances by regulating evaporative heat loss (He,sweatin g and thermal panting)t o keep body temperature down to the set point. Both methods have proved successful in evolutionary terms but have very different implications for commercial livestock farming. Maintenance of homeothermy by regulation ofH p in pigs and poultry is associated with a very limited ability to regulate He). The wide thermoneutral zone for ruminants isdu e to their ability to regulate He over a wide range at little metabolic cost. InNorther n Europe many pigs and poultry are kept in controlled environment houses at an air temperature (Ta)o f 20°Co r above,a far higher temperature than that deemed necessary for ruminants. This isno t done toavoi d cold stress but tominimis e food costs. A plump hen strutting in a farmyard at 10°C isno t cold but she eatsmor e food than at 21°C (air temperature in battery cage units)s o produces more heat without distress as an inevitable consequence of her elevated metabolism. It iswel l known that pigs and poultry are more sensitive to heat stress than ruminants because of their lesser ability to regulate He. The preferred air temperature for pig and poultry production is therefore usually the maximum air temperature for optimal production; i.e. on the border of heat stress. Thus as Ta is increased above 21°C there isa steady improvement in food conversion efficiency in broilers asH p falls,bu t a decline in weight gain due toa decrease in food intake, itself due toa n inability to dissipate heat produced during themetabolis m of food (Webster, 1983a). Inmos t intensive pig and poultry houses,short-ter m regulation of Ta isachieve d entirely by control of ventilation. Occasional very hot days in generally warm environments create conditions inside such houses that cannot be controlled by ventilation alone. In these circumstances it isnecessar y to increase evaporative cooling either by wetting the animals or "fogging" the air (Curtis, 1983). Fig.1(b)show s Hp decreasing in ruminants above the upper limit of the thermoneutral zone. This differs from classical temperature/metabolism curves (seeMonteit h &Mount , 1974)whic h indicate an increase inH p above the upper critical temperature. However, this increase can be attributed largely to thewor k of thermal panting in acute,sever e and ultimately intolerable heat stress. Themor e normal and sustainable response of a ruminant (or any homeotherm)t o prolonged heat stress is to reduce Hp mainly (and possible entirely)b y reducing food energy intake.

Thermogenesis in farm animals

In the first analysis the inevitable heat production of any homeotherm may berelate d to (1)bod y size,usuall y defined byWeigh t (kg)0"75 (Kleiber, 1961); (2)physiologica l state; (3)activity ; (4)intak e of metabolizable energy (IME, kJ/d). To thisma y be added any energy costs ofmaintainin g homeothermy. Under standard, thermoneutral conditions and when activity isminimal ,

16 0 75 Hp (kJ/d)= aW ' + bIME

The coefficient a defines basalmetaboli c rate (at least in theory), b defines the heat increment of feeding (HIF, kJHp/kJME). Sensible heat loss toai r isusuall y related to body surface area, itself a function ofW0'67 > so that, in theory, Hp increases with respect to the capacity to lose heat asanimal s get bigger, but the effect isquit e small relative to the effect on Hp of IME. For example,

Heat production Body weight(kg) kJ/kg d Watts/m2

Laying hen 2 650 88 Adult sheep, maintenance 70 450 81 Beef cow,maintenanc e 500 550 115 Dairy cow,4 0 litre milk/day 600 1200 256

The laying hen hasa higher Hp (kJ/kg .d)tha n the adult sheep or cow at maintenance due to themetaboli c cost of daily egg production. Expressed aswatts/m 2, these effects largely cancel out. The biggest difference in Hp (watts/m2) is between the adult beef cow at maintenance and the dairy cow in full production. It follows from this that differences in heat tolerance are largely unrelated to body size and can mainly be attributed to differences inHI F and physiological state. Thisargumen t leads to the useful generalisation that the more productive an animal the more sensitive it is to heat and the more tolerant it is to cold. There are clear differences within species in basal metabolism expressed per unit of body size (kJ/kg0-75.d), e.g. between Bos indicus (280-300)an d Bos taurus (320-380)an d between beef (320-350)an d dairy (350-380)type s within Bos taurus (Webster, 1983b). These are often related to differences in endocrine status,correctl y but not very helpfully. In fact most of these differences can beaccounte d for in terms of differences in relative proportions of themajo r body organs and tissues and a knowledge of organ-specific metabolic rates. In farm animals the tissues of the stomach, intestines,live r and kidney may contribute only 5-6% to body mass but 50%t o total thermogenesis (Webster, 1989). Koong,Ferrel l and Nienaber (1985)hav e elegantly demonstrated the extent to which physiological state (as determined by genotype and prior nutrition)ca n effect basal metabolism in pigs (Table 1). They brought pigs toa fixed weight (40kg)b y either a low:high or high:low feeding strategy. Plane of nutrition had major effects on visceral weight (V),LH:H L = 1*30- 1-42. However,th e absolute increase in visceral weight was very small relative to body weight, V/B increasing from approximately 4 to 6%, but this increase was enough to cause an increase of 30-50% in fasting Hp, from 340-480 kJ/kg^*'^d. These observations are entirely consistent with my conclusion (Webster, 1989)tha t approximately 50%o f thermogenesis in farm animals and a far greater proportion of variation between animals in thermogenesis can be attributed to processes of digestion and metabolism inevitably linked tomaintenance , growth, lactation (etc.)rathe r than to hormonally

17 mediated thermogenic mechanisms designed tokee p animals warm or dissipate excess energy.

Table 1. Effects of different feeding regimes (low:high,L H and high:low, HL)o n organ size and fasting metabolism in lean and obese pigs (Koong et al. (1985).

Lean Obese LH HL LH HL

Weight (kg)bod y (B) 41-6 40-2 39-6 40-8 Liver, stomach & intestines (V) 2-46 1-90 2-29 1-61 (V/B,%) 5-9 4-7 5-8 3-9 Fasting Hp,kJ/kgWu* .d 495 330 460 347 Ratios LH:HL, viscera 1-30 1-42 fasting Hp 1-50 1-32

A very recent publication from Burrin et al. (1990)confirm s this work and demonstrates further that the effect of feed intake on changes in the relative contribution of visceral organs towhole-bod y thermogenesis can beattribute d primarily to differences in organ size rather than to metabolic activity per unit masso f tissue. It remains possible that themetaboli c rates of some tissuesma y change in response to environmental stimuli in a way that is not absolutely linked to essential metabolic processes. Brown adipose tissue is an obvious example (Girardier, 1983)bu t this doesno t make a significant contribution to thermogenesis in farm animals after the first few days of life. Huntington &McBrid e (1988)hav e estimated the contribution of different metabolic processes to visceral and whole-body thermogenesis in sheep (Table 2). They have been able toaccoun t for 72% of visceral metabolism and 29%o f whole-body metabolism in terms of specific metabolic functions in the tissues of the gut and liver. One of these functions,N aK -ATPase dependent respiration (membrane pumping)ma y beamenabl e to change during adaptation to heat or cold in a way that is independent of essential metabolic processes but this remains unproven.

Table 2. Estimated contribution of different metabolic processes to thermogenesis in sheep (Huntington &McBride , 1988)

Metabolism in gut and liver Proportion of total0 „ consumption (J/kJ) Gut & liver Whole body

Protein synthesis 177 71 Protein degradation 68 27 Na+K-ATPase 255 102 Substrate cycling 90 36 Urea synthesis 125 50 Total 715 286

18 Adaptation towar m environments

Adaptation of a species towar m environments involves farmor e than just themaintenanc e of homèothermy. Perhaps themos t successful feature of the adaptation of ruminants to hot,ari d conditions in the tropics is their mechanism for recycling urea. In the dry season a ruminant may have little to eat but standing hay high in fibre and low in protein. Such food will sustain neither themaintenanc e requirement of the animal nor that of the rumen microbes. The ruminant therefore catabolises protein from muscle, skin (etc.)t o provide energy. The end product of protein catabolism, urea, isno t lost but returned to the rumen, re-incorporated intomicrobia l protein, digested and re-absorbed asamin o acids. Thismechanis m (1)restore s amino acids to a malnourished animal; (2)reduce s urea excretion and therefore water loss; (3)maintain s themicrobia l population of the rumen and thereby appetite for fibrous food. The most effective forms of adaptation to the problem of excessive heat load, so far as the producer isconcerned , are based on increased ability to lose heat,especiall y by evaporation, and reflect solar radiation from the hair coat (Hafez, 1968). Species and strains have also adapted to the tropics by reducing Hp. The important,and - unsolved, question for the animal scientist iswhethe r this reduction inH p iso r isno t inextricably linked toa reduction in metabolic capacity to grow or lactate. A low potential for a synthetic function like growth,whethe r determined by genotype or environment, implies also a low appetite. When animals are chronically exposed to heat, everything tends to slow down; protein synthesis,hea t production, food intake, hormone secretion rates. Yousef et al. (1968)demonstrate d that thyroid secretion rates fell during prolonged exposure of cattle to heat even when food intake was maintained by force-feeding through a rumen fistula. What nobody has yet demonstrated, at least tom y knowledge, iswhethe r in these circumstances the food would be converted with the same efficiency to lean tissue growth or milk production. Iwoul d predict not. There have been relatively few good energy balance studies on productive farm animals during adaptation to heat. One such is that of Khub Singh and Bhattacharya (1991)wh o adapted native Indian Hariana cattle (Bos indicus)an d a range ofF l crossbred cattle to air temperatures ranging from 17t o 37°C (vapour pressure 10-12 mmHg). Some of their results are summarised in Table 3.

Table 3. Energy exchanges of cattle after 18day s exposure to different air temperatures (from Khub Singh & N.K.Bhattacharya, 1991)

Hariana Brown Swiss Holstein/ n 7_. /Hariana Hariana Energy exchange(kJ/kgU .d) IME Hp ' IME Hp IME Hp

Airtemperature(°C )1 7 923 286 864 324 913 330 22 944 269 919 330 888 325 27 921 261 903 305 896 313 32 780 250 711 270 694 288 37 686 234 665 259 653 262 Difference(17t o27-37 ) 243 38 233 60 246 60

19 The absolute values in Table 3 need to be viewed with caution. Careful measurements were made of dry matter intake but ME values were estimates. Measurements of Hp were made for6-mi nperiod s 18h after feeding, and therefore almost certainly underestimate 24-hr metabolic rate. Nevertheless, the trends within the experiment are instructive. At thermoneutrality (17-27°C)Harian a ate asmuc h as the Fl hybrids (929 v. 899kJ/kg°' 75.d)bu t produced less heat (272 v. 322,P <0-01). All three strains tended to reduce both IMEan d Hp above 30°Can d to much the same degree. The proportional decrease inH p in theHarian a and Holstein/Hariana was 14%an d 19%respectively . Other measurements indicated that Hariana but none of theF l hybrids could tolerate exposure to 42°C. What ismor e important in practice is that under less severe conditions the affect of heat on Fl hybrids was similar to that for Bos indicus. The reduction in Hp was,o n average,26 %o f that in IME. Even assuming that 24-hr Hp was underestimated by asmuc h asone - third (seeWebster , 1989), the reduction inH p does not exceed 40%,a value less than predicted HIF for the diet. This strongly suggests that changes inH p brought about by acclimation to heat in individual animals can be attributed simply to the inevitable consequences of reduced food intake. The absolute difference inH p between Hariana and Fl hybrids may be attributed to physiological state but,fo r reasons given earlier, this may simply reflect different proportions of organs with different organ-specific metabolic rates.

Manipulation of the heat increment of feeding

In ruminants,HI F can alter Hp per unit body size by at least a factor of two. It is logical therefore to examine themanipulatio n ofHI F as a way of ameliorating the effects of warm environments. Some thought has been given to producing diets that generate relatively high ratios of propionate:acetate on the assumption that propionate is utilised more efficiently for growth thus reducing HIF. Thisassumptio n is probably incorrect inmos t practical circumstances (MacRae & Lobley, 1982). However, diets which generate high acetate:propionate ratios happen to be high roughage dietswhic h carry a high energy cost of digestion (Webster, 1980), or,i n this context,a relatively high and prolonged HIF. The only practical approach tomanipulatin g HIF involves feed diets that are relatively rapidly digested at a time of day (or night) when heat stress isminimal . Thismay , of course,b e economically unrealistic.

Upper critical temperature

When heat stress is defined, as in this paper,i n termso f its inhibitory effect on thermogenic processes associated with digestion, growth, lactation (etc.), it isno t possible to'construct an absolute definition for upper critical temperature (UCT), the upper limit of the thermoneutral zone. Estimates of UCT vary according towhethe r heat stress is considered to bea problem of productivity orwelfare . A young bull eating sufficient to gain 2kg/day may elect,whe n air temperature exceeds 25°C, to eat a little less and grow a little slower. One cannot however conclude that the animal isan y more distressed than the barn yard hen electing to eat a littlemor e at aT a of 10°C. Khub Singh& Bhattacharya (1991)hav e suggested alternative definitions for UCT based on significant departures of different physiological measurements from valuesa t thermal neutrality (Table4) .

20 Table 4. Criteria for determination of upper critical temperature (from Rhub Singh & Bhattacharya, 1991)

Hariana BrownSw l ss/ Holstein/ Hariana Hariana

UCT, day1 8 fromhea tproductio n 34 0 29-0 29-0 respirationrat e 30 5 26-0 26-0 rectaltemperatur e 34 0 28-5 27-0

The decline inH p isprobabl y themos t sensitive indicator of heat stress sufficient to affect production. This is not ameasur e that can bemad e in practice but it does correspond quite closely both to the temperature above which food intake declines significantly and rectal temperature rises. Respiration rate is not,i nm y opinion,a particularly good predictor of UCT inBo s taurus and sheep since it varies throughout the thermoneutral zone. In pigs, poultry and possibly Bos indicus increased respiration rate isa good indicator of Heat stress since these species maintain thermal comfort mainly by regulating Hp. It is reasonable to conclude that inal l farm animals,adaptatio n of the species or acclimation of the individual to ensure comfort and survival in warm environments is inevitably (and perhaps absolutely) correlated with a reduced capacity for synthetic processes like growth and lactation. This conclusion may be bleak but it provides a powerful antidote to claims (e.g.)fro m enthusiastic breeders that their animals will outperform indigenous breeds "anywhere in theworld. " More constructively, it suggests that more attention should be given to the manipulation of microclimate than to themanipulatio n of metabolism.

References

Burrin.D.G., Ferrell.C.L.,Britton,R.A . & Bauer,M., 1991. Level of nutrition and visceral organ size and metabolic activity in sheep. British Journal of Nutrition 64:439-448. Curtis,S.E., 1983. Environmental management inanima l agriculture. Iowa State University Press,Iowa . Girardier,L., 1983. Brown fat:a n energy dissipating tissue.In : Mammalian thermogenesis.Eds .L.Girardie r &M.J.Stock , pp.50-98. Chapman & Hall,London . Hafez,E.S.E., 1968. Adaptation of domestic animals. Lea & Febiger, Philadelphia. Huntington,G.B.& McBride,B.W. , 1988. Ruminant splanchmic tissues: energy costs of absorption and net metabolism. In:Biomechanism s regulating growth and development.Eds .G.L.Steffer s & T.S.Rumsey. pp.313-328. Kluwer,Boston . Khub Singh & Bhattacharya,N.K., 1991. Thermosensitivity of Bos indicus cattle and their Fl crosses with three breeds ofBo s taurus. Animal Production (in press). Kleiber,M., 1961. The fire of life. Wiley, New York.

21 Koong.L.J.,Ferrell,CL . &Nienaber.J.A. , 1985. Assessment of the interrelationship among levels of intake and production, organ size and fasting heat production in growing animals. Journal of Nutrition 115:1383-1390. McDowell,R.A., 1972. Improvement of livestock production inwar m environments. Freeman,Sa n Francisco. MacRae.J.R.& Lobley,G.E., 1982. Some factorswhic h influence thermal energy losses during themetabolis m of ruminants. Livestock Production Science 9:447-456. Monteith.J.& Mount,L.E., 1974. Heat loss from animals andman . Butterworth, London. Webster,A.J.F., 1980. The energy costs of digestion and metabolism in the gut.In :Digestiv e Physiology and Metabolism inRuminants . Eds. Y.Ruckebusch& P.Thivend. pp.423-438.MT P Press,Lancaster . Webster,A.J.F., 1983a. Nutrition and the thermal environment. In: Nutritional Physiology of farm animals. Eds.J.A.F.Roo k &P.C.Thomas . pp.639-669. Longman,London . Webster,A.J.F., 1983b. Energetics ofmaintenanc e and growth. In: Mammalian thermogenesis. Eds.L.Girardier &M.J.Stock , pp.178-207. Chapman & Hall,London . Webster,A.J.F., 1989. Bioenergetics, bioengineering and growth. Animal Production 48:249-269. Yousef.M.K., Hahn.L. &Johnson,H.S. , 1968. Adaptation of cattle. In: Adaptation of domestic animals.Ed . E.S.E.Hafez, pp.233-245. Lea & Febiger,Philadelphia .

GROUPI GROUP II

Too Thermoneutral Too -cold j 1 hot

! ~""p

i i i i 20 30 40 Air temperature (°C)

Fig.1. Patterns of heat exchange in farmanimals : (a)Grou p I,e.g . pigsan d chickens,animal s who maintain homeothermy primarily by regulating Hp. (b)Grou p II,e.g . horses and ruminants,animal s who maintain homeothermy primarily by regularing He. (from Webster, 1983a).

22 Reproductive responses under high temperature conditions.

A. Berman Department of Animal Science, Faculty of Agriculture, Hebrew University, Rehovot, Israel

Summary Inwar m climates conception rate isdepresse d during the hotter months to 10-20%,eve n when food quantity and quality are not limiting factors. This isassociate d with lower progesterone, abnormal patterns of progesterone secretion, shorter corpus luteum life spans, higher estrogen in preovulatory phase, high incidence of ovulations without behavioural oestrus manifestation, smaller mammary glands, reduced calves birth weight, and decreased milk yields.Thi s wide range of phenomena is associated with redistribution of blood flow in the body, which occurs even on mild rises in body temperature. The redistribution of blood flow diverts blood flow towards body periphery, compromising that to' reproductive tract. This redistribution isenhance d by lactation, as mammary gland blood flow is unaffected by peripheral vasodilation. Normal reproductive function can be restored in summer by extended heat stress relief.

Introduction Reproductive performance is impaired by seasonal high temperatures. Even when feed isfreel y available, its quality is not significantly affected by season, and animals have adequate shade, conception rate on first insemination may fall from about 50% inwinte r to about 15-20%i n the summer (Israel Herdbook data, 1989). Extension of interval from calving to conception to 140 days may result in economic losses equivalent to 920 kg FCM (Weiler & Folman, 1990). In the hot months, reproductive performance is reduced concomitantly in a large part of the animals in the herd. The milk production of the herd is then temporarily lowered as a result of less animals calving. The reduced milk production in summer isdu e to the effects of heat stress on concurrent milk production and reproductive performance of the individual cow, aswel l as the summation of the effects of impaired reproductive performance on the milk production of the herd as a whole.Maintainin g normal reproductive performance istherefor e important for the economic efficiency of milk production. The following presents a view of the elements composing the problem and an approach to its alleviation in the farming system. General components The possibility that the summer depression in reproductive performance is induced by photoperiod seems rather remote. Photoperiod induces anestrus in beef breeds, and the effect is independent of thermoperiod (Schillo et al, 1983). The conception rate of Israeli Holstein heifers

23 (at about 15month s of age) is almost constant during the year, while that of cows is strongly seasonal (Israel Herdbook data, 1990). These do not suggest photoperiod as a dominant factor on reproductive performance in dairy cattle in the subtropics. Milking frequency, three times daily in Israel, is an unlikely adverse factor, since such frequency was shown without effect on reproductive performance (Amos et al, 1985). High ambient temperature, acting through body core or body periphery temperature sensors, may affect reproductive function either directly or indirectly. Ambient temperatures are well known to reduce food intake and induce a negative energy balance. Changes in skin temperature or body temperature elicit immediate changes infeedin g responses in both isolated and near-natural experimental situations (Berman &WoTfenson , 1988). On the other hand, high yielding dairy cows most commonly are in a negative energy balance after calving, which impairs reproductive function. It is probable that reduced appetite at high ambient temperatures amplifies the negative energy balance and its impact on reproduction. Direct effects of ambient temperature on reproductive function probably can be observed in short term studies mostly. It ispossibl e that specific effects of high temperature on reproductive function may interact with negative.energy balance to enhance the seasonal depression in reproductive performance. Male effect on female reproductive performance Summer weather in subtropical climates iswithi n the range known to impair spermatogenesis in bulls (Amir et al, 1982; Skinner & Louw, 1966). In the past, a deterioration of summer semen quality in Israel had been recorded (Schindler, 1954). However, appropriate shelter design and heat stress relief reduced seasonal differences in semen quality to a probably nonsignificant level (Amir et al, 1982). This sets disruption of female reproductive function as main factor in the low summer fertility.

High temperature effects on female reproductive function. Female reproductive function patterns consist of strongly interrelated and interdependent events,whic h are integrated into the estrous cycle and eventually evolve into pregnancy. Viewing these events as particulate stages, or underrating their interdependence, may lead to overestimating the value of particular events in the infertility syndrome. The probability of conception was found to be related to the plasma progesterone concentrations in the estrous cycle preceding insemination (Folman et al, 1973; Fonseca et al, 1983). This may be related to the finding that heat stress, assessed by THI, significantly affected conception rate on all days from day n before breeding to the second day after breeding, with the exception of day -l. The conditions inwhic h the ovulatory follicle develops also play a probable role, as the largest decline in conception rate per unit increase irrTH I occurred during the phase of ovulatory follicle growth period (-6 to -2 days relative to estrus) (Ingraham et al, 1974, 1976). This might be related to the observation that pre-estrus plasma estrogen was significantly reduced by heat stress (Gwazdauskas et al, 1981), although opposite changes were also observed (Rosenberg et al, 1982). Plasma cholesterol, a precursor for steroidogenesis, was negatively related to THI in cows inth e first month postpartum in Louisiana (Ingraham et al, 1982). In Holstein cows,

24 monitoring of estrus behaviour for 96 h inwinte r and summer indicated that in cold weather estrous behaviour as mounting activity was double that in hot weather in Indiana (28%v s 14%);cow s in hot weather interacted more by rubbing and licking than cows in cold weather (Pennington et al, 1985). In Holstein virgin heifers, natural or controlled heat stress did not have consistent effects on length of estrous cycle, but consistently shortened duration of estrus from 20 to il h (Gangwar et al, 1965). Efficient relief of heat stress by combination of sprinkling with forced ventilation (Flamenbaum et al, 1986)fro m day -l to day +8 relative to estrus,markedl y affected oestrous behaviour in Israeli Holstein cows inwhic h estrus was synchronzed by PRID (7 d) and prostaglandin F2a (l d before PRID removal) inmidsummer . It increased incidence of standing heat from 45%t o70% , and reduced incidence of anestrous from 33%t o 12%(He r et al, 1988). Progesterone concentration on days 4-15 of the estrous cycle were significantly lower in the summer than in the winter, and this was associated with differences in conception rate (Rosenberg et al, 1977). Reducing ambient heat stress in summer increased plasma progesterone concentrations (Rosenberg et al, 1982; Gauthier, 1983; Her et al, 1988). It is noteworthy that relieving stress of heat also significantly reduced incidence of abnormal luteal cycles (Her et al, 1988). Relieving heat stress also increased conception rate on first inseminations from 22%i n controls to 52%,bu t the latter was still significantly lower than that attained inwinte r cows (Folman et al, 1979). Cooling dairy cows to maintain their rectal temperature at 38.9 C vs 40.l C in shaded controls in Saudi Arabia for 8 days or 16 days starting from 2 d prior to estrus increased conception rate from 16.7 to 28.6% (Wise et al, 1988). This was associated with higher P4 (+1 ng/ml) in cooled animals over days 5 to 20 post AI. No differences in plasma estradiol or Cortisol were recorded. It should be noted, that relieving heat stress for short periods, did not restore reproductive performance to the patterns observed in cool environments. Itwa s only when heat stress was relieved so that animals maintained body temperatures below 39.o C for extended periods that normal reproductive performance was attained (Flamenbaum et al, unpublished data). This might be linked to the relation between progesterone concentration inth e cycle preceding AI and conception rate (Folman et al, 1973). Also, corpus luteum function may be affected by heat stress effects on the ovulatory follicle from which it formed or heat stress during corpus luteum formative stage. In the rabbit, exposure to heat stress for 2 days during the formative stage of the corpus luteum, significantly reduced size of large luteal cells and plasma progesterone concentrations (Wolfenson & Blum, 1988). In cultured bovine luteal cells progesterone production is affected by 2 h exposure to 40 C; also, their response to stimulation by forskolin, which is independent of LH receptors functional integrity, was significantly lower in cells obtained from summer than from winter corpora lutea (Meidan & Wolfenson, in preparation). These suggest a possible effect of body temperature during the formative stages of corpus luteum on its subsequent development and function, as well as an immediate, direct effect which is independent of previous exposure.

25 Heat stress and prenatal development. Exposure of ewes to heat during early pregnancy induces embryonic loss; embryo mortality was largest when heat stress was imposed on days following mating, and increased with extension of heat stress exposure to over 90%embry o mortality (Dutt et al, 1959). In lambs born to heat stressed ewes cerebral malformations were found (Hartley et al, 1974). In ewes exposed to heat stress during middle or later stages of pregnancy, marked reductions in birth weight (about 30%an d larger)wer e observed (Yeates, 1958;Alexande r & Williams, 1971), which were independent of the food intake of ewes (Cartwright & Thwaites, 1976). Exposing beef cows to heat stress (12 h at 37C) in early pregnancy reduced fetal weight on day 17 and increased embryonic mortality by 25%v s controls (Biggers et al, 1987). In rats, increases of body temperatures inmother s by more than 2C above normal or exposure of embryos to temperatures more than 2C above normal maternal was needed to induce embryo development abnormalities (Zusman and Ornoy, 1990). This may be related to the fact that in sheep and goats there was no evidence for passive body temperature lability as an adaptation to exposure to thermal stress for 7 h (Johnson, 1971). However, exposure of dairy cattle to heat stress (32 C constant) for 2 weeks, increased by about lC the regulated body temperature (Berman & Kibler, 1959). Prepartum heat stress effects The sensitivity of reproductive functions to the stress of heat is also evident inth e later stages of pregnancy, involving mammary development and its subsequent function. Relieving heat stress effects in the last 3 or 2 months of pregnancy significantly increased calves birth weight (Collier at al, 1982,Wolfenso n et al, 1988). Milk production was significantly increased only inth e latter study, inwhic h body temperatures were maintained at a lower level. In another study (Berman et al, unpublished data) only mammary development in the last weeks of prepartum, as assessed by photomorphometric method, was enhanced in multiparous (but not primiparous)cows , and nomil k production response was attained when heat stress was relieved to a minor degree. Milk production response to prepartum cooling was associated with rise in prepartum progesterone (Wolfenson et al, 1988). This might be associated with the finding that prepartum P4wa s higher in cows sired by and bred to bulls of high predicted differences for milk yield than in cows sired by and bred to bulls with assummed zero estimated predicted differences for milk yield (Eley et al, 1981). Blood flow redistribution in the body Blood flow is redistributed in the body during heat stress, so that a larger part flows in parts active in heat dissipation, enhancing heat loss from the body. Such redistribution might impair blood flow the reproductive tract, and impair its function. These aspects were examined in our laboratory, using the rabbit as an experimental animal. Blood flow to the genital tract, including ovaries,wa s markedly compromised during even mild body temperature increases which induced peripheral vasodilation (Berman et al, 1983). In this animal, such reduction in

26 blood flow was associated with lower blood progesterone and impaired embryo development. Plasma progesterone concentrations were highly correlated with ovarian blood flow. Also, blood flow to the uterus in heat stressed pregnant animals was further reduced by lactation. These might provide a possible explanation for heat stress affecting so many and diverse facets of reproductive function.

Effect of negative energy balance. Conception rate of virgin heifers in the US has remained constant since 1951, when itwa s equal to that of cows; in the latter, conception rate had declined from 66%t o 51% in 1985. This suggests an effect of increasing annual milk production from 4500 to 7500 kg, and not a genetic selection for lower fertility (Butler and Smith, 1989). In the Israeli Holstein cattle, in about 92000 lactations between 1980 to 1986, there was no indication for a genetic relationship between milk production and fertility (Weiler, 1989). In Holstein cattle in North Carolina, days to first detected estrus increased, estrus detection rates decreased, and days to first insemination occurred later postpartum with milk yield increasing relative to herdmates (Fonseca et al, 1983). These suggest an extension of postpartum anestrus period with rising milk yield. Concentrations of plasma LH are reduced by negative energy balance occurring after 5 to 10day s postpartum in dairy cows (Schallenberger, 1985; Schallenberger & Walters, 1985). Undernutrition coupled with suckling by calves in beef cows reduces both LH and FSH for prolonged periods, resulting in postpartum anestrus (Terqui et al, 1982). Due to ease of calf removal and repeatability of responses, the suckled beef cow has been used as experimental animal for the study of the relationship between nutrition and reproductive function. In such cows, removal of calves increased LH peak concentrations and pulse frequency. Undernurishing these cows, or induction of acute hypoglycemia and low insulin concentrations, inhibited the responses of LH to calf removal, but this was without much effects on postpartum ovarian activity (Rutter and Manns, 1987). These might be seen as evidence for possible role of glucose (and/or insulin) in the regulation of LH function. Another possible pathway for interaction between nutrition and reproduction lies in the opioid pathways. LH is released following excitation of the ventral noradrenergic tract in the brainstem. Excitatory noradrenergic neurons of this tract synapse on GnRH producing neurons in the anterior hypothalamus and preoptic area. Opioids inhibit these noradrenergic neurons, preventing GnRH production. Opioids are normally involved in the control of appetite, stimulating food intake. Administration of opioid antagonist concomitant with GnRH to undernurished ovariectomized sheep increased the amplitude of LH pulses as well as its basal concentration by 25-30%relativ e to previous opioid antagonist-free period (Butler and Smith, 1989). This suggests that during negative energy balance opioids exert a negative effect upon LH response to GnRH. A moderate increase in body energy stores in the preceding cooler season might possibly compensate for reduced food intake during the summer. This might then be a possible alternative to heat stress relief, which was tested in 82 Israeli-Holstein cows, fed during late lactation and dry period to reach body condition scores of 3.8 vs 2.6 by two to three weeks before partum in early summer. High body condition at partum

27 reduced the interval from parturition to resumption of ovarian cyclicity (estimated by the average time between date of last P4 concentration below lng/m l and that of first concentration of P4 above lng/ml )fro m 32 to 26 d (Wolfenson et al, 1988). However, in cows inwhic h body condition at partum isexcessivel y high, 3.5 and more, longer intervals to first estrus and conception were recorded, and required more inseminations per conception (Garnsworthy & Jones, 1987). This may be related to the more severe negative energy balance occurring in such cows in early lactation. It seems that negative energy balance effects on reproductive function apparently center on prevention of LH response to GnRH mostly, thereby preventing onset of cyclicity. This is in contrast to the many aspects of reproductive function which are affected by the stress of heat. The possibility that the two stressors might interact to produce a different infertility syndrome can not be negated. REFERENCES Alexander, G. & D. Williams. 1971. Heat stress and development of the conceptus in domestic sheep. J. Agric. Sei. 76:53. Amir, D.,M . Bar-El, D. Kalay & H. Schindler. 1982.Th e contribution of bulls and cows to the seasonal differences in the fertility of dairy cattle in Israel.Anim . Reprod. Sei. 5:93. Amos, H.E., T. Kiser & M. Loewenstein. 1985. Influence of milking frequency on productive and reproductive efficiencies of dairy cows. J. Dairy Sei. 68:732. Bar Anan R. and A. Genizi. 1981.Th e effects of lactation, pregnancy and calendar month on milk records.Anim . Prod. 33:2810. Berman, A. & H.H. Kibler. 1959. Effect of clipping the coat on the thermoregulatory reactions of dairy heifers. Nature 183:606. Berman, A., A. Lublin, A. Meltzer, & D. Wolfenson. !983.Temperatur e and fertility. Proc. 5th Inter. Conf. Production Disease in Farm Animals. Uppsala, Sweden, p275-278 . Biggers, J.D., R.D. Geisert, R.P. Wetteman & D.S.Buchanan . 1987. Effect of heat stress on early embryonic development in the beef cow. J. Anim. Sei. 64:1512. Blake, R.W., B.T. McDaniel, R.E. Pearson, R.E. McDowell and C.J. Wilcox. 1986. Genetic methods of improving dairy cattle for the South: A review and prospects from Regional Project S-49. J. Dairy Sei. 69:1098. Butler W.R. and R.D. Smith. 1989. Interrelationships between energy balance and postpartum reproductive function in dairy cattle. J. Dairy Sei. 72:767. Cartwright, G.A. and C.J. Thwaites. 1976. Foetal stunting in sheep. The influence of maternal nutrition and high ambient temperature on the growth and proportions of the merino foetus. J. Agric. Sei. 86:573. Collier, R.J., S.G. Doelger, H.H. Head, W.W. Thatcher & C.J. Wilcox. 1982. Effects of heat stress during pregnancy on maternal hormone concentrations, calf birth weight and postpartum milk yield of Holstein cows. J. Anim. Sei. 54:309. Dutt, R.H., E.F. Ellington & W.W. Carlton. 1959.Fertilizatio n rate and early embryo survival in sheared and unsheared ewes following exposure to elevated air temperatures. J. Anim. Sei. 18:1308.

28 Eley, D.S.,W.W . Thatcher, H.H. Head, R.J. Colllier and R.J. Wilcox. 1981. Periparturient endocrine changes of conceptus and maternal units in Jersey cows bred for milk yield. J. Dairy Sei.64:296. Flamenbaum, I., D. Wolfenson, M. Mamen & A. Berman. 1986.Coolin g dairy cattle by combination of sprinkling and forced ventilation and its implementation in the shelter system. J. Dairy Sei. 69:3140. Folman, Y., A. Berman, Z. Herz,M . Kaim, M. Rosenberg, and S. Gordin. 1979.Mil k yield and fertility of high yielding cows in a subtropical climate during summer and winter. J. Dairy Res. 46:411. Folman, Y., Miriam Rosenberg, Z. Hertz and M. Davidson. 1973.Th e relationship between plasma progestrone concentration and conception in postpartum cows maintained on two levels of nutrition. J. Reprod. Fert. 34:267. Fonseca, F.A., Britt, J.H., B.T.McDaniel , J.C. Wilk, and A.H. Rakes. 1983. Reproductive traits of Holsteins and Jerseys. Effects of age, milk yield, and clinical abnormalities on involution of cervix and uterus, ovulation, estrous cycles, detection of estrus, conception rate and days open. J. Dairy Sei. 66:1128. Gangwar, P.C., C. Branton, &D.L. Evans. 1965.Reproductiv e and physiological responses of Holstein heifers to controlled and natural climatic conditions. J. Dairy Sei. 58:222. Garnsworthy, P.C. & G.P. Jones. 1987.Th e effect of body condition of dairy cows at calving and dietary protein supply on voluntary food intake and performance in dairy cows.Anima l Production 44:347. Gauthier, D. 1983.A technique fir improving the fertility of French Friesian cows in a tropical climate. Effect on plasma progesterone profile.Reprod . Nutr. Dev. 23:129. Gwazdauskas, F.C., W.W. Thatcher, C.A. Kiddy, M.J. Paape, & W.C. Wilcox. 1981. Hormonal patterns during heat stress following PGF2a -tham salt induced luteal regression in heifers.Theriogenolog y 16:131. Hartley, W.J., G. Alexander & M.J. Edwards. 1974. Teratology 9:299-304. Her, E.,D . Wolfenson, I. Falmenbaum, Y. Folman, M. Kaim, and A. Berman. 1988. Thermal, productive, and reproductive responses of high yielding cows exposed to short term cooling in summer. J. Dairy Sei. 71:1085. Ingraham, R.G., L.C. Kappel, E.B. Morgan & D.B. Babcock. 1982. Temperature-humidity versus seasonal effects on concentration of blood constituents of dairy cows during the pre and postcalving periods. Proc. 2nd Inter. Livestock Environment Symp. Ames, Iowa. Ingraham, R.G., D.D.Gillett e & W.C.Wagner . 1974.Relationshi p of temperature and humidity to conception rate of Holstein cows in subtropical climate. J. Dairy Sei. 57:476. Ingraham, R.G., R.W. Stanley, & W.C.Wagner . 1976.Relationshi p of temperature and humidity to conception rate of Holstein cows inHawaii . J. Dairy Sei. 59:2086. Johnson, K.G. 1971.Bod y temperature lability in sheep and goats during short-term exposures to heat and cold. J. Agric. Sei.77:267 . Petitclerc, D., L.T. Chapin, R.S. Emery, and H.A. Tucker. 1983. Body growth, growth hormone, prolactin and puberty response to photoperiod and plane of nutrition in Holstein heifers. J. Anim. Sei. 57:892. Pennington, J.A., J.L. Albright, M.A. Diekman & C.J. Callahan. 1985. Sexual activity of Holstein cows: seasonal effects. J. Dairy Sei. 68:3023.

29 Rosenberg, Miriam, Z. Herz, M. Davidson and Y. Folman. 1977. Seasonal variations in plasma progesterone levels and conception in primiparous and multiparous dairy cows.J . Reprod. Fert. 51:363. Rosenberg, Miriam, Y. Folman, Z. Herz, I. Flamenbaum, A. Berman, and M. Kaim. 1982. Efect of climatic conditions on peripheral concentrations of LH, progesterone, and oestradiol-170 in high milk-yielding cows. J. Reprod. Fert. 66:139. Schallenberger, E. 1985. Gonadotropins and ovarian steroids in cattle. III. Pulsatile changes of gonadotrophin concentrations in the jugular vein postpartum. Acta Endocrinol. 109:37. Schallenberger, E. and D.L. Walters. 1985. Endocrine mechanisms contributing to postpartum anoestrus in dairy and beef cattle, pp 206-209 in Endocrine causes of seasonal farm animals. F. Ellendorf and F. Elsaesser, ed. Martinus Nijhoff Publ. Boston MA, US. Schillo, K.K., P.J. Hansen, L.A. Kamwanja, D.J. Dierschke, and E.R. Häuser. 1983. Influence of season on sexual development in heifers: age at puberty as related to growth and serum concentrations of gonadotropins, prolactin and progesterone. Biol. Reprod. 28:329. Schindler, H. 1954.Seasona l fluctuations in fertility and other characteristics of bull semen used for artificial insemination in Israel. Bull.Res . Counc. Isr. 4:184. Skinner, J.D. & G.N. Louw. 1966. Heat stress and spermatogenesis in Bos indicus and Bos taurus cattle. J. Appl. Physiol.21:1784 . Terqui, M., D. Chupin, D. Gauthier, N. Perez, J. Pelot, and P. Mauleon. 1982. Influence of management and nutrition on postpartum endocrine function and ovarian activity in cows. Factors influencing fertility in the postpartum cow. H. Kark and E. Schallenberger, Ed., Curr. Topics Vet. Med. Anim. Sei. 20:384. Yeates, N.T.M. 1958. Foetal dwarfism in sheep: an effect of high atmospheric temperatures during gestation. J. Agric. Sei. 51:468. Weller, J.I. 1989. Genetic analysis of fertility traits in Israeli dairy cattle. J. Dairy Sei. 72:2644. Weller, J. I.& Y. Folman. 1990; Effects of calf value and reproductive management on optimum days to first breeding. J. Dairy Sei. 73:1318. Wildman, E.E., Jones, G.M., P.E. Wagner, R.L. Boman, H.F. Troutt & T.N. Lesch. 1982.A dairy cow body condition scoring system and its relationship to selected production characteristics. J. Dairy Sei. 65:95. Wise M.E.,R.E . Rodriguez, D.V. Armstrong, J.T. Huber, F. Wiersma, and R.F. Hunter. 1988.Fertilit y and hormonal responses to temporary relief of heat stress in lactating dairy cows.Theriogenolog y 29:1027. Wolfenson, D. & Orly Blum. 1988. Embryonic development, conception rate, ovarian function and structure in pregnant rabbits heat stressed before or during implantation. Anim. Reprod. Sei. 17:259. Wolfenson, D., I. Flamenbaum &A . Berman. 1988.Hyperthemi a and body energy store effects on estrous behaviour, conception rate, and corpus luteum function in dairy cows. J. Dairy Sei.71:3497 . Wolfenson, D., I. Flamenbaum & A. Berman. 1988.Dr y period heat stress relief effect on prepartum progesterone, calf birth weight and milk production. J. Dairy Sei.71:809 . Zusman I.& A. Ornoy. 1990. Embryonic resistance to chemical and physical factors:manifestation , mechanism, role in reproduction and in adaptation to ecology. Biol.Rev . 65:l.

30 Productiveresponse so fruminant sunde rhig htemperatur econdition s

P.Berbigie r INRA,Laboratoir ed eBioclimatologie ,B.P .81 , 33883VILLENAV ED'ORNO NCedex ,Franc e

Summary

Heatstres si nruminant si smainl ydu et othei rinabilit yt odissipat e theextra-hea to ffood .Therefore ,the yhav et oreduc ethei rfoo dintak e andi nconsequenc ethei rleve lo fproduction . Dairycow sar emos taffected ,becaus eo fthei rver yhig hleve lo f intake.Hea tstres sma yb eallieviate db yshading ,sprayin gan dfannin g theanimal sdurin glat egestatio nan dlactation . Milkproductio no fhea tadapte dnativ ean dcrossbre dcows ,ewe san d goatsdoe sno tsee mt ob ever ydependen to nheat .Improve ddair ybreed s ofshee pan dgoat sar eno tmuc huse dfo rmil kproductio ni nho t countries.Milkin gbuffaloe sar erathe rsensitiv et oheat ,bu tonl yfe w dataar eavailable . , Meatproductio ni sles saffecte db yheat ,foo dintak elevel so fmea t animalsbein glower .Moreover ,mos to fmea tproductio ni sensure db y nativeo rcrossbre danimals ,th esuperiorit yo fproductiv ebreed sfro m temperatecountrie sno tbein gs oeviden ta sfo rmilk . Woolproductio no fshee pi sreduce db yhea tstress ,thi seffec tbein g relatedt ofoo dintake ,bu tincrease db ysu nradation . Extradescriptors :war mclimates ;hea tstress ;mil kproduction ;mea t production;woo lproduction ;dair ycows ;cattle ;sheep ;goats ; buffaloes.

Introduction

Animalproductio ni nwar mclimate si smainl yaffecte db ythre e environmentalfactors : -tropica ldisease s -foo dsuppl yshortage s -hea tstres s Heatstres si sprovoke db yth einabilit yt odissipat ehea tproductio n bymean so fthermolysis :th eanimal shav ethe nt oreduc ei tb y diminishingvolontar yfoo dintake ,i norde rt olowe rextra-hea to f digestion.Thi sdecreas eis ,t osom eextent ,counterbalance db ysom e improvementi ndigestibility ,probabl ydu et oretarde dabsorptio no f nutrientsi nth edigestiv etract ,bu ta sa whol einduce sa decreas ei n foodutilization ,a greate rpar to fmetabolizabl eenerg ybein guse dfo r maintenanceand ,moreover ,maintenanc erequirement sincreasin gwit hhea t stress (Rohr& Oslage ,1987) •N owonde rthe ntha tdair ycow sfro mEurop e orNorther nAmerica ,havin ga ver yhig hfoo dintak ecapacity ,ar eth e mostsensitiv et ohea tstress . Inthi spaper ,w ewil lrevie wth eeffect so fhea to nmilk ,mea tan d woolproductio no fdomesti cruminants ,accordin gt oth edifferen t species.Thoug hw ewil lmentio nnativ ean dcrossbre danimals ,w ewil l stresso nimprove dbreeds ,an dmainl yo ndair ycows .W ewil lprivileg e fieldresults ,a sthos efro mclimati cchamber sar eno talway s reproduciblei nfiel dconditions .

31 Milkproductio n

Cattle

Milkproductio ndecrease swhe nincreasin ghea tload ,particularl yfo r high-producingdair ycow s (Hafez,1968) ,whil eBrahma ncow s (about4 litres/daya ttherma lneutrality )remai nalmos tunaffected .I n conditionso fextrem ehea tstress ,th esuperiorit yo fimprove ddair y breedsi salmos tcancelled .However ,thes ear efigure sfo rconstan t temperatures.I nmos tpractica lcases ,lowe rnigh ttemperature sallo w thecow st orecove rfro mhea tstress . Nativebreeds . NativeAfrica nbreed sar ever ypoo rmil kproducer s (less than100 0k gmil kpe rlactatio ni nmos tcases ,n omor etha n250 0k gi n experimentalstations ,Cozzi ,1973) .Thei rmil kproductio ni sunaffecte d byhea tstress ,th eonl ysignifican tclimati ceffec tbein gfoo dshortag e relatedt odr yseaso n (Berbigier,1988) . MilkingZebus . TheIndia nmilkin gZebus ,als ofoun di nLati nAmeric a andAustalia ,hav ea highe rleve lo fproduction :u pt o220 0k gpe r lactationi nBrazi li nfiel dexperiment s (asmuc ha sFriesia nan d Flemishcow si nth esam eenvironment) ,u pt o300 0k gi nexperimenta l stations (Bonnadonna,1973) .Thes ecow sd ono tsee mt ob ever ySensitiv e toheat ,eve ni fopposit eresult sar ereporte d (Laie tal. ,1987) . Crossbreeds. Crossbreedingbetwee nEuropean ,India nan dAfrica ncow s wasattempte di nvariou scountrie s (Mahadevane tal. ,1962 ;Hayman , 1974; Katpatal,1977 ;Letenneur ,1978 ;Madalena ,I98I ;Ponc e& Bell , 1985).Th eoptimu mpercentag eo feac hbloo ddepend so nbreed san d environmentalcharacteristic s (Berbigier,1988) . Dairycows . Dairycow sfro mtemperat ecountrie sar eth emos tsensitiv e tohea ta sthei rfoo dintak ecapacit yi sth ehighes to fan ytyp eo f cattle.Thei rreproductiv efunctio ni sfirs taffecte db yhea tstres s (Bonachea,1981 ;Berma ne tal. ,1984 ;Bading ae tal. ,1985 ;Vermeulen , 1987);i tha sheav yconsequence so nmil kproduction ,particularl yo n milkavailabilit yaccordin gt oseason . Theeffec to fhea tstres so nactua lmil kproductio n (i.e. after calving)i sclosel yrelate dt oth edecreas ei nvoluntar yfoo dintak e beyonda critica lthreshol do fhea tload ,expresse di nterm so fambien t temperatureor ,better ,a sa climati cinde x (forinstanc eTHI) .Johnso n (I985)state stha tther ei sa linea rdecreas ei nha yconsumptio nan d milkproductio nbeyon d18° Cambien ttemperatur e (respectively-0.2 3k g and-O.2 6k gpe rTH Iuni tincrease) .However ,inspectio no fhi sresult s showstha tth ecritica lTH Ima yb eabou t76 ,correspondin gt o2 6t o32° C ambienttemperatur eaccordin gt orelativ ehumidity .Hour so fTH Iabov e thethreshol dexplai nth edecreas ei nmil kproductio ncompare dt o thermalneutrality :Llnvil l& Pardu e (1985),i nSout hCarolina ,fin d thatdail ymil kproductio ni sbes texplaine db yhour so fTH I7 4i nth e preceeding4 days ,an dhour so fTH I8 0yesterday . Negativeeffect so fhig hTH Io nmil kproductio nincreas ewit hleve lo f production:fo rHolstei nher di nUSA ,Berr ye tal . (1964)suggeste dth e followingequation :

MDec=-2.370-I.73 6N L+ 0.0247 4(NLJ(THI )

WhereMDe cwa sabsolut edeclin ei nmil kproductio n (lbpe rda ype rcow ) andN Lnorma lleve lo fproductio n (lbpe rda ype rcow) .I tca nb esee n thatth eregressio ncoefficien tfo rTH Idepend spositivel yo nNL ,s o thata nincreas ei nN Lincrease sth eeffec to fTH Io nMDec . Thoughincomin gradiatio nshoul db etake nint oaccoun t (Ingrahame t al.,197 9;Buffingto ne tal. ,I98I )a swel la swindspee dan ddail y

32 temperaturefluctuations ,TH Ii snevertheles sa goo dtoo lfo rclimati c comparisons.However ,car emus tb etake nt ocomput ei to ntim espan s correspondingt oth eexplaine dvariable :fo rinstance ,fo rmil k productiono rfoo dintake ,dail ymean smus tb eused ,whil ehourl ymean s arebette rfo rphysiologica ldata .Car emus tals ob etake nno tt omi xu p dailyo rseasona lstresse san dcontinuou sexposur et otropica lclimates . Therei sa ver ybi gamoun to ffiel dresult so ndair ycows ,an dth e wayst oalleviat ehea tstress .Fo rHolstei ncows ,i nmos tsubtropica l countries,th esumme rdeclin ei nmil kproductio nseem st ob eabou t8 - 12ÏÜ,a swel lfo rver yhig hmil kyield si nIsrae l (about900 0k gi na 305-daylactation ,Berma ne tal. ,1984 )a sfo rlowe ryield si nSouther n USA (400 0t o600 0k gpe r300-da ylactation ,Branto ne tal ,1974) . However,man yauthor sd ono tspecif ywhethe rth ecow sar eshade do rnot . Accordingt oRodrigue ze tal.(1985) .i nFlorida ,mil kproductio nbegin s todecreas ebeyon d2 9C maximu mtemperature ;fa tan dprotei nconten t decreaselinearl yfro m9. 4 °Conwards ,i nagreemen twit hth estatemen t thatth ebes ttemperatur efo rmil kproductio ni sapproximatel y1 0C (Thompson,1985) ;solids-not-fat ,tota lsolid san dlactose-minera l decreaseabov e2 2°C .I nHawa i (warmhumi dclimate) ,unshade dHolstei n cowssho wa greate r (202)decreas ei nmil kproductio na tth ebeginnin g oflactatio n (Ingrahame tal. ,1979) . Heatstres sdurin glat epregnanc yha sa detrimenta leffec to nfoeta l size,and ,therefore ,subsequen tmil kproductio n (Thatcheret^al. ,1980 ; Bermane tal. ,1984) . Themos tlargel yuse dmea no fallievatin ghea tstres si sshade ,an d manyo fth eprecedin gdat ainclud ethi seffect .I nFlorida ,fo r Holstein-Friesiancows ,th eeffec to fshad eo nmil kyiel dma yb e significant (10.7%,Roman-Ponc ee tal. ,1977 )o rno t (Roman-Poncee t al.,I98I) .Addin gspray san dfan st oshad edurin gsumme rstil l increasesmil kproductio no fHolstein-Friesia ncattl e (7-9%i nMissouri , Igonoe tal. ,1987 ,11.6 #i nFlorida ,Buckli ne tal. ,1989 ,16.5 2i n China,Huan ge tal. ,I986) .Buckli ne tal .(1989 )demonstat eth e economicinteres to fthi smethod .I nIsrael ,prepartu mcoolin gb yspray s andfan sdurin gth ehot-dr yseaso nimprove ssubsequen t150-da ymil k productionb y9.4 *(Wolfenso ne tal. ,1988) . Geneticselectio no nsweatin gabilit yo rcoa tcolou rdoe sno tsee mt o have,u pt onow ,give nmeaningfu lresults .Feedin gth eanimal swit hmor e concentratei norde rt oreduc eth eextra-hea to fdigestion ,an d restoringth eioni cequilibriu mdisturbe db ypantin gan dsweatin gar e efficientmean st oalleviat ehea tstres s (Chandler,1987) .

Otherruminant s

Sheep. Therear ever yfe wdat ao nth eeffec to fhea to nmil kyiel do f ewes.Lactatin gewe so fEuropea n (Finnx Dorse tx Rambouillet ,Abdall a etal. ,1989 )a swel la sEgyptia norigi n (Aboul-Nagae tal. ,1981 ) reducethei rmil kproductio ni nrespons et ohea tstress .However ,th e firstresult sar efro mclimat echamber ,and ,i nth esecon dpaper , climatei sno tdescribed . Goats. Whengoat sar eallowe dt odrink ,a decreas ei nmil kproductio n isonl yobserve dfo ranimal sno tadapte dt ohea tan dsuddenl yheat - stressed (Esmail,1986 ;Kama le tal. ,1987) - Waterbuffaloes . Thoughth ewate rbuffal oi sknow nt ob erathe r sensitivet ohea t (Shafie,1985) .littl ei sknow no ntherma leffect so n milkproduction .Moreover ,th eresult sar econflictin g (Laie tal.,1986 ; Yadav& Gupta ,1985) •Mor edetail sar eneede do nexperimenta l conditions.

33 Meatan dwoo lproductio n

Cattle Exposuret osunshin ei na tropica lenvironmen tinduce sa decreas ei n foodintak ean dgrowt hrat eonl yfo rEuropea nbee fcattl ewit ha dar k andthic kcoat ;white-coate dShorthor ncattl eonl ysho wa slightl ylowe r growththa nBrahma ncattle ,th efigure sbein gth esam ewhe nth ewhit e coati sshor t (Finche tal. ,1984) .Fiel dresult sfro mAustali asho w thatth eeffec to fhea tloa d per se ongrowt hi sreduce deve no n Europeancattle ,th emai nenvironmenta leffect sbein gparasites , ophtalmyan dnutritiona lvariation s (Frisch& Vercoe ,1978) -Th eproble m ofparasitis mi sparticularl yacut ei nth eplace so fAfric awher e sleepingsicknes si sendemic ,impedin gimplantatio no fan ycattl ebu t littletrypanotoleran ttaurin ebreeds . Tropicalbee fcattle . Therei sno tevidenc eo fan ysensitivit yo f tropicalbee fcattle ,neithe rnativ eno rimprove d (forinstanc e Brahman),t ohea tstess ;moreover ,thei rgrowt hrate sar equit egoo d whenwel lfe d (Lhoste,1977) :th efigure ssee mt ob eabou t0.7-0. 8 kg/dayfo rgrowin gAfrica nzeb ubull sfe dconcentrate .I nGuadeloupe , forvery-wel lfe dCreol e (Zebu)bulls ,w eobserve dgrowth so f&.8 5 kg/dayfo ra 7-month sfattening .Ther ewa sa sligh tdecreas ei nfoo d intakefo rth ebull skep ti nsunshine ,but ,a srecta ltemperatur ewa s notaffected ,w ethough ti twa sa behavioura ladaptatio nt oheat :growt h rateremaine dunaffecte d (Berbigier& Sophie ,1986) . Crossbreeding. Improvingnativ eanimal swit hexoti cbloo dma yincreas e growthrate :w eobtained ,i nGuadeloupe ,mea ngrowth so n7 month so f I.06kg/da yfo rshade dan dunshade dLimousi nx Creol egrowin gbulls . However,suc hcrossbreeds ,a swel la sBrahma ncattle ,requir efrequen t treatmentsagains ttick san dworms .I nhumi dtropica lcountries ,i t seemst ou stha tth ebes twa yfo rimprovin gmea tproductio nshoul db e geneticselectio no nloca lbreeds .I nsubtropica lan ddr ytropica l countries,crossbreedin gshoul db efeasible . Improvedbreeds . Meatproductio nfro m"temperate "bee fcattl ei s practisedmainl yi ndevelope dsubtropica lcountries .Ragsdal ee t al.(I957)observe ddecrease si ngrowt hrat ea t80°F .I nCalifornia , Kellye tal . (1962)improve db y 3.2% thegrowt hrat eo fHerefor dbul l calves (O.933t o1.01 9kg/d )b ygivin gthe macces st oshade .Sprayin g givesconflictin gresult s (Garrett,1963;Morriso ne tal. ,1973) -Othe r methods,a sus eo ffan s (Garrette tal. ,i960) ,coolin gdrinkin gwate r (Lofgreene tal. ,1975) .evaporativ ecoolin g (LeroyHahn ,1985) ,see m unnecessary. Fromresult so fGome sD aSilv a (1973.1986 )an dTurne r (1984),i t seemstha tgeneti cselectio no ntrait ssuc ha slo wincrease si nrecta l temperatureunde rhea tstress ,swea tpotential ,coa tcolou ran d insulation,etc... .shoul db efeasible .However ,t oou rknowledge ,n o practicalresul tha sbee nobtaine du pt onow .

Otherruminant s

Sheep:mea tan dwoo lproduction . Resultso nshor ngrowin glamb sfro m USA (Ames& Brink ,1977 )sho wa rathe rgrea tsensitivit yt oheat ,dail y weightgai nan dfee defficienc ya t3 5° Cambien ttemperatur ebein g respectively21 %an d 21%o fvalue sa tthermoneutrality .However ,thes e datafro mcontrolle denvironment sma yb eno trepresentativ etropica l fieldconditions . Sheepwit hdee pwool ycoat sar efoun di ndr ysunn yclimates ,suc ha s Australia:i tseem stha twoo lprovide sa shelte ragains tsu nradiation ,

34 heatproductio nbein gdissipate dmainl yb yrespirator yevaporation .O n thecontrary ,i nles ssunn yhumi dtropica lclimates ,th eefficienc yo f evaporativehea tlos si slowere dan donl yhair-coate dshee pwit ha lowe r bodyinsulatio nca nsurviv e (Thwaites,1985) • InTexas ,Thwaite s (1985)claim stha tgrowt hrat eo flamb si sreduce d inho tenvironments .I nIndi a(ho tdr yclimate ,37-V Cmea nai r temperature,32 #mea nrelativ ehumidity )Kari me tal.(1984 )fai lt ofin d anyeffec to fshad ean devaporativ ecoolin go nfoo dintak ean dgrowt h rateo fMerin ox Chokl aweane rlambs .Woo lyiel di smuc hincrease d(b y about35X )fo rshee pexpose dt osunshin ecompare dt oshade dones . Onth econtrary ,non-radiativ ehea tstres ssuffere db yadult sreduc e woolgrowth ,i nrelatio nt ofoo dintak ereduction ,an dewe sstresse da t theen do fgestatio nla ydow nles swool-producin glamb s(Thwaites , 1985). Goats. Meatproductio no ftropica la swel la scrossbre dgoat sdoe sno t seemt orespon dt ohea tstress :i nGuadeloupe ,nativ edwar fCreol ebuck s aswel la sAlpi nx Creol ecrossbreed shav eth esam egrowt hrat ean d carcasscompositio nwit han dwithou tshelte r (Sergente tal. ,1987 ; Berbigiere tal. ,1987 ;Berbigier ,1988) . Waterbuffaloes .Fro mvariou sauthor scite db yShafi e (1985).fee d intakeo fgrowin gbuffaloe sha sa stron gnegativ ecorrelatio nwit hai r temperature.Afif ie tal . (1985)als ofin dsignifican tnegativ e correlationsbetwee ndail yweigh tgai no non ehand ,an dcoa tscpr e(fro m smootht owooly )an dcoa tdept ho nth eothe rhand . Conclusion

Fromth eabov eresults ,i tca nb econclude dthat ,fo ral ldomesti c ruminants,mil kan dmea tca nb eproduce db yloca lbreed san d crossbreeds,thu savoidin gt oa larg eexten tth eproblem so fhea t stress.Moreover ,geneti cpotential s ofloca lan dcrossbre dcattl efo r meatproductio nar eofte nquit egood ,s otha tusin gpur eEuropea nbee f cattledoe sno tsee mt ob eth ebes tsolution .O nth econtrary ,geneti c potentialsfo rmil kar emuc hhighe rfo rspecialize ddair ycow stha nfo r anyothe rcattl ebreed ,an dthei rus ei nho tcountries ,wit happropriat e techniquesfo rallieviatin ghea tstess ,i softe neconomicall y interesting.However ,previsio no fmil kyiel dfro mclimat eneed sfurthe r research:TH Iseem sa goo dinde xfo rregiona lprevisions ,bu tshoul d havet ob eimproved :radiatio nan dwindspee dar eno ttake nint oaccount , dailyfluctuation so fclimati cparameter sar ecancelled ,an dther ear e notman yfiel ddat awit ha goo ddescriptio no fclimate . Littlei sknow no nwoo lproductio no fsheep :i tseem stha thea tstres s decreaseswoo lproduction ,bu ttha tsu nradiatio ni sa stimulu sfo rwoo l growth,a sa mea nfo rprotectin gshee pfro mradiation .

References

Abdalla,E.B. ,Kotby ,E.A .& Johnson ,H.D. ,1989 .Environmenta lhea t effectso nmetaboli can dhormona lfunction san dmil kyiel do f lactatingewes .Journa lo fDair yScience , 12 (Supplement1):471 . Aboul-Naga,A.M. ,El-Shoboksky ,A.S. ,Marie ,I.F .& Moustafa ,M.A. , I98I.Mil kproductio nfro msubtropica lnon-dair ysheep .1 .Ew e performance.Journa lo fAgricultura lScienc e (Cambridge)97:297 -301. Afifi,Y.A. ,Merai ,I.F. ,Gaber ,H .& Ibrahim ,I.L. ,1979 .Relationshi p betweenhai rcoa tcharacter san dphysiologica lan dproductiv e performanceso fFriesia ncattl ean dbuffaloes .Agricultura lResearc h Review57:127-137 -

35 Ames,D.R. ,& Brinks ,D.R. , 1977.Effec to ftemperatur eo nlam b performancean dprotei nefficienc yratio .Journa lo fAnima lScienc e 44:136-140. Badinga,L. ,Collier ,R.J. ,Thatcher ,W.W .& Wilcox ,C.J. , 1985.Effect s ofclimati can dmanagemen tfactors "o nconceptio nrat eo fdair ycattl e ina subtropica lenvironment .Journa lo fDair yScienc e68:78-85 . Berbigier,P .& Sophie ,S.A. , 1986.Performance sd ecroissanc ee t d'abattaged etaurillon sLimousin sx Créole se tCréole sélevé sa u soleile tà l'ombr ee nGuadeloup e (Antillesfrançaises) .Revu e d'Elevagee td eMédecin evétérinair ede sPay stropicau x39:82-89 . Berbigier,P. ,Sergent ,D .& Sophie ,S.A. , I987.Thermoregulatio nan d meatproductio no fAlpi nx Creol ean dCreol ebilly-goat si n Guadeloupe.Proceeding so fth e4 fchInternationa lConferenc eo nGoats , Brasilia,Marc h8-13 ,1987 ,Volum e2 :137 0(Abstract ) Berbigier,P. ,1988 .Bioclimatologi ede sruminant sdomestique se nzon e tropicale.INR APubl. ,Versailles.23 7P . Berman,A. ,Flamenbaum ,I .& Wolfenso nD. ,1984 .Alleviatio no fhea t stressan dit simpac to nreproductio ni ndair ycattle .In :Th e reproductivepotentia lo fcattl ean dsheep .INR APubl. ,Versailles . 125-137. Berry,I.L. , Shanklin,M.D .& Johnson ,H.D. ,1964 .Dair yshelte rdesig n based on milk production decline as affected by temperature and humidity.Transaction so fth eASA E7:329-331 . Bonachea, S.T., I98I. Efecto de los factures climâticos sobre la fertilidadd el avac aHolstein .Revist aCuban ad eReproducció nAnima l 7:49-59. Bonnadonna,T. ,1973 -Considerazion isull aproduzion ed ilatt ene i tropici.Zootecni aveterinaria ,28 :4-14 . Branton.C,Rios ,G. ,Evans ,D.L. ,Farthing ,B.R .& Koonce ,K.L. ,1974 . Genotype-climatican dothe rinteractio neffect sfo rproductiv e responsesi nHolsteins .Journa lo fDair yScienc e57:833~84l . Bucklin,R.A. ,Strickland ,J.T. ,Beede ,D.K .& Bray ,D.R. ,1989 .Co w coolingpay si nhumi dFlorida .Hoard' sDairyma n134:344-357 - Buffington,D.E. ,Collazo-Arocho ,A. ,Canton ,G.H. ,Pitt ,D. ,Thatcher , W.W.& Collier ,R.J. ,I98I .Black-globe-humidit y index (BGHI)a s comfortequatio nfo rdair ycows .Transaction so fth eASA E24:711-714 . Chandler,P.T. ,1987 .Problem so fhea tstres si ndair ycattl eexamined . Feedstuffs25:15-16,35 . Cozzi,P. ,1973 -L eprincipal ipopolazion ibovin edell'Africa .Rivist a diAgricoltur aSubtropical ee tropical e67:24-55 . Esmail,S.H.M. ,1986 .Acclimatizatio no fimprove dSaane ngoat si nNort h Yemen.Worl dRevie wo fAnima lProduction ,22:4-7 . Finch,V.A. ,Bennett ,I.L .& Holmes ,CR. , 1984.Coa tcolou ri ncattle : effecto ntherma lbalance ,behaviou ran dgrowth ,an drelationshi pwit h coattype .Journa lo fAgricultura lScienc e (Cambridge)102:l4l-l47 . Frisch,J.E .& Vercoe ,J.E. ,1978 .Utilisatio nde sdifférence sraciale s pourl'amélioratio nd el acroissanc ede sbovin ssou sle stropiques . RevueMondial ed eZootechni e25:8-12 . Garrett,W.N. ,Bond ,T.E .& Kelly ,CF. ,i960 .Effect so fai rvelocit y ongain san dphysiologica ladjustment so fHerefor dsteer si na hig h temperatureenvironment .Journa lo fAnima lScienc e19:60-66 . Garrett,W.N.,I963 .Environmenta lresearc hwit hbee fcattle .Pape r presenteda tth e4l st annualmeetingo fth eASA EPacifi cCoas tSection . Gomesd aSilva ,R. ,1973 -Improvin gtropica lbee fcattl eb ysimultaneou s selectionfo rweigh tan dhea ttolerance .Heritabilitie san d correlationso fth etraits .Journa lo fAnima lScienc e37:637-642 . Gomesd aSilva ,R. ,1986 .Seleçà bpar aadaptaça od ebovino sao s trópicos.Communicatio na tth e"1 °cicl od epalestra ssobr e

36 BioclimatologiaAnimal" ,Botucatu ,SP ,Brazil . Hafez,E.S.E. ,1968 .Environmenta leffect so nanima lproductivity .In : Hafez,E.S.E. :Adaptatio no fdomesti canimals .Le a& Febiger , Philadelphia.74-93 - Hayman,R.H. ,1974 .Th edevelopemen to fo fth eAustralia nMilkin gZebu . WorldRevie wo fAnima lProductio n11:31-35 . Huang,CS. ,Li ,R.Z .& Cao ,G.X. ,1986 .Effect so fincreasin gai rspee d ando fsprinklin go nth eperformance so fdair ycow si nth eho tseason . Journalo fNanjin gAgricultura lUniversit y2:102-109 . Igono,M.O. ,Johnson ,H.D. ,Steevens ,B.J. ,Krause ,G.F .& Shanklin , M.D., 1987.Physiological ,productive ,an deconomi cbenefit so fshade , sprayan dfa nsyste mversu sshad efo rHolstei ncow sdurin gsumme r heat.Journa lo fDair yScienc e70:1069-1079 . Ingraham,R.H. ,Stanley ,R.W .& Wagner ,W.C. ,1979 -Seasona leffec to f thetropica lclimat eo nshade dan dnonshade dcow sa smeasure db y rectaltemperature ,adrena lcorte xhormones ,thyroi dhormone ,an dmil k production.America nJourna lo fVeterinar yResearc h40:1792-1797 - Johnson,H.D. ,1985 .Physiologica lresponse san dproductivit yo fcattle . In: Yousef,M.K. :Stres sphysiolog yi nlivestock ;Volum e2 :Ungulates . CRCPress ,Boca-Raton .3-23 . Kamal,T.H. ,Mostafa ,S.I. ,Habib ,A.A. ,Elmasr yA.M. ,Abdelsamee ,A.M. , Abolnaga,A.I. ,Kassab ,F.A .& Abdelhamid ,A.M. ,1987 .Developemen to f ane whea ttoleranc einde xfo rselectin gproductiv egoat sfo rth e tropics.Isotop eaide dstudie so nlivestoc kproductivit yi n Mediterraneanan dNort hAfrica ncountries .Proc .o fth efina lresearc h Coordinationmeeting ,Rabat ,23-2 7marc h1987 .85-93 . Karim,S.A. ,Singh ,M .& Rai ,A.K. ,1984 .Performanc eo fcrossbre d weanerlamb sunde rho tenvironmenta lconditions .India nJourna lo f AnimalScienc e54:1087-1090 . KatpatalB.G.,1977 -Croisemen tde sbovin slaitier se nInde.1 : Développementde scroisement sinterraciaux .Revu eMondial ed e Zootechnie27:36-42 . Kelly,CF. ,Bond ,T.E .& Garrett ,W.N. ,1962 .Shad eare arequirement s forbee ffee dlots .California nAgricultur e14:11-12 . Lai,S.N. ,Verma ,D.N .& Husain ,K.Q. ,1986 .Effec to fai rtemperatur e andhumidit yo nth efee dconsumption ,cardio-respirator yrespons ean d milkproductio ni nMurra hBuffalo .Narendr aDev aJourna lo f AgriculturalResearch ,1:96-101 . Lai,S.N. ,Verma ,D.N .& Husain ,K.Q. ,I987 .Effec to fai rtemperatur e andhumidit yo nth efee dconsumption ,cardio-respirator yrespons ean d milkproductio ni nHaryan acows ,India nVeterinar yJournal ,64:115 - 121. LeRoyHahn ,G. ,1985 .Managemen tan dhousin go ffar manimals .In : Yousef,M.K. :Stres sphysiolog yi nlivestock ;Volum e2 :Ungulates .CR C Press,Boca-Raton .151-174 . Letenneur,L. ,1978 .Di xannée sd'expérimentatio nsu rl ecroisemen td u bétailN'Dam ax Jersiai se nCôte-d'Ivoire .Revu eMondial ed e Zootechnie27:36-42 . Lhoste,P. ,1977 -Not esu ru nessa id eproductio nd ejeune sbovin s précocesa uCameroun .Revu ed'Elevag ee td eMédecin evétérinair ede s Paystropicau x30:309-314 . Linvill,D.E .& Pardue ,1985 .Summertim edair yproductio ni nSout h Carolina.Paper ,America nSociet yo fAgricultura lEngineer sn °85 - 4025.1 0pages . Lofgreen,G.P. ,Givens ,R.I. ,Morrison ,S.R .& Bond ,T.E. ,1975 .Effec t ofdrinkin gwate rtemperatur eo nbee fcattl eperformance .Journa lo f AnimalScienc e40:223-229 . Madalena,F.E. ,I98I .Stratégie sd ecroisemen tde sbovin slaitier sa u

37 Brésil.Revu eMondial ed eZootechni e38:23-30 . Mahadevan,P. ,Galukande ,E.B .& Blac kJ.Q. ,1962 .A geneti cstud yo f theSahiwa lgradin gu pschem ei nKenya .Anima lproductio n4:337"342 . Morrison,S.R. , Givens,R.L .& Lofgreen ,G.P. ,1973 •Sprinklin gcattl e forrelie ffro mhea tstress .Journa lo fAnima lScienc e36:428-431 • Ponce,P .& Bell ,L. ,1985 .Lactanci ad evaca sHolstei nFriesian ,3/ 4 Holsteinx 1/ 4Ceb ûy 5/ 8Holstei nx 3/ 8Cebû .1 .Efect ode lgrup o racialy l ainteracció nrebafio-raz asobr el aproducció ny composició n delèche .Revist ad eSalu dAnima l7:333"338 . Ragsdale,A.C. ,Cheng ,CS .& Johnson ,H.D., o1957 -Effect so fconstan t environmentaltemperature so f50° Fan d80° Fo nth egrowt hrespons eo f Brahman,Sant aGertrudi san dShorthor ncalves .Missour iAgricultura l ExperimentalStatio nResearc hBulleti n642 . Rodriguez,L.A. ,Mekkonen ,G. ,Wilcox ,C.J. ,Martin ,F.G .& Krienke , W.A.,1985 .Effec to frelativ ehumidity ,maximu man dminimu m temperature,pregnanc yan dstag eo flactatio no nmil kcompositio nan d yield.Journa lo fDair yScienc e68:973-978 . Rohr,K .& Oslage ,H.J. ,1987 .Fee dconversio nan dnutrien t partitioning.In :Milk-Th evita lforce .D .Reide lPublishin gCo .595 - 604. Roman-Ponce,H. ,Thatcher ,W.W. ,Buffington ,P.E. ,Wilcox ,C.J .& Va n Horn,H.H. ,1977 -Physiologica lan dproductio nresponse so fdair y cattlet oa shad estructur ei na subtropica lenvironmen tJourna lo f DairyScienc e60:424-430 . Roman-Ponce,H.H. ,Thatcher ,W.W .& Wilcox ,C.J. , I98I.Hormona l interrelationshipsan dphysiologica lresponse so flactatin gdair ycow s toa shad emanagemen tsyste mi na subtropica lenvironment . Theriogenology16:131-138 . Sergent,D. ,Berbigier ,P .& Sophie ,S.A. , 1987-Influenc ed uclima t tropicalhumid ee td univea ualimentair esu rl athermorégulatio ne t lesperformance sd ecroissanc ee td'abattag ed ejeune sbouc sCréole s enGuadeloupe .Annale sd eZootechni e36:121-138 . Shafie,M.M. ,1985 .Physiologica lresponse san dadaptatio no fwate r buffalo.In :Yousef ,M.K. :Stres sphysiolog yi nlivestock ;Volum e2 : ungulates.CR CPress ,Boca-Raton .67-80 . Thatcher,W.W. ,Wilcox ,C.J. ,Collier ,R.J. ,Eley ,D.S .& Head ,H.H. , I98O.Bovin econceptus-materna linteraction sdurin gth epre -an d postpartumperiods .Journa lo fDair yScienc e63:1530-1540 . Thompson,G.E. ,1985 .Lactatio nan dth etherma lenvironment .In :Yousef , M.K.:Stres sphysiolog yi nlivestock ;Volum e1 :Basi cprinciples .CR C Press,Boca-Raton .122-131 . Thwaites,C.J. , I985.Physiologica lresponse san dproductivit yi nsheep . In:Yousef ,M.K. :Stres sphysiolog yi nlivestock ;Volum e2 :ungulates . CRCPress ,Boca-Raton .25-38 . Turner,H.G. ,1984 .Variatio ni nrecta ltemperatur eo fcattl ei na tropicalenvironmen tan dit srelatio nt ogrowt hrate .Anima l Production,38:417-427 . Vermeulen,G.T.J. ,1987 .Hea tstres san dit seffec to nmil kproduction , milkqualit yan dreproduction .Nationa ldair ycattl eperformanc ean d progenytestin gscheme .Republi co fSouth-Africa .Annua lReport . 1:73- 101. Wolfenson,D. ,Flamenbaum ,I .& Berman.A. ,1988 .Dr yperio dhea tstres s reliefeffect so nprepartu mprogesterone ,cal fbirt hweigh tan dmil k production.Journa lo fDair yScienc e71:809 -8l8. Yadav,J.L .& Gupta ,L.R. , I985.Effec to fdifferen thousin gsystem so n theproductio no fbuffaloe sdurin gsummer .India nJourna lo fDair y Science38:245-249 .

38 Breedingprogramme s for improved dairyproductio n in tropical climates

E.P.Cunningha m FAOAnima lProductio n andHealt h Division Abstract The developing dairy industry in tropical countries is largely based on crossbred cattle produced by breeding cows of localbreed swit h imported semen.Thi spaper ,base d ona n FAO study, reviews the experimental evidence produced by more than 40 crossbreeding studies conducted over the last three decades. The conclusions are that on an average the Bos taurus breeds used have about 100% higher milk production capacity than the local breeds. This is an additive genetic effect. In addition, there is a positive heterosis effect amounting to about 30%. Substantial additive and heterotic effects were also demonstrated for ageat firs tcalvin g and forcalvin g interval. ' Alternative breeding strategies to exploit these two sources of genetic variation are explored. It is being concluded that, in most circumstances, the development of syntheticpopulation swit ha 50%o rmor eBo stauru scontent , isth ebes tstrategy . The comparison of Friesian, Brown Swiss and Jersey sources of Bos taurus genes showed consistent breed differences, with Friesian having the highest values for milk-yield, andJerse y forreproductiv etraits . Introduction The developing countries collectively contain three- quarters of humanity, and two-thirds of theworld' s cattle, yet they produce only 20%o f the world's milk output. Milk availability per head in the developing world is therefore less than one-tenth what it is in the developed countries. Atth e sametime ,th edevelopin g countrieswil l doublethei r population in the next generation. The real need and demand for milk in developing countries is therefore very large, andth edefici t islikel yt obecom esteadil ymor eacute . At the same time, the promotion of milk production systems is seen as one of themos t broadly favourable paths ofrura l and overall economic development inman ycountries . This has been amply demonstrated many times, and with particular success in India. Milk production provides a regular supply of the most critical nutrients to the most vulnerable sections of society. For producers, it provides an income sourceo na dail y basis,an dwit h arelativel y low risk factor. The basal diet for milking animals can be supplied inman y cases from otherwiseunusabl e crop residues and forages. The modest cash flow from milk sales has been shown in many instances to be the key to increased fertiliser and other inputs which enhance crop production. The care and management of milking animals provide socially 39 desirablewor kopportunities . For all of these reasons, the development of milk production is a central part of thedriv e for food security andeconomi cgrowt hthroughou tmuc h ofth edevelopin gworld . Throughout the tropics,th e local cattle populations are usually of Zebu (or Bos indicus) types. These have considerable tolerance for the climatic, nutritional and disease challenges which are present in these areas. However, since they have generally not been systematically selected formil kproductio n inth epast ,thei r capacity for dairy output is limited. In contrast,man y cattle breeds in the developed world have a history of effective selection for milking ability. However, when transferred to the tropics, particularly the humid tropics, they do not have the physiological resilience to cope with the environmental stresses.Crosse s betweenthes etw otype shav ebee n shown in many countries to combine themil k producing ability of the temperate breeds with the climatic adaptability of the tropical breeds. Typically, such crossbreds produce 100% more milk per lactation than the local breeds. This outstanding performance is partly due to the straight combination ofth eattribute s ofbot hparents ,an dpartl y to hybrid vigor which is specific to the first (or Fl) cross. In general, when these first crosses are interbred, or backcrossed to eitherparent ,muc ho fth emeri t ofth e first cross islost . Crossbreeding Temperate andTropica l Cattle The principles of organised selection programs are no different in developing countries from those already in use elsewhere. However, in tropical countries most attention is currently being given to the exploitation of the potential forcrossbreedin gsystems . In a recent publication (Cunningham & Syrstad, 1988) we have attempted to draw together all of the valid experimental results which we could find on the comparison of Bos indicus and Bos taurus cattle,an d their crosses.I n all, 46 usable data sets were located. Many were Indian, though many other countries were also represented. Though mosto fth epublication s arefro mth elas ttwent yyears ,th e data insom ecase sg obac ka decad eearlie rtha nthat . In each case, itwa s required that there should be valid comparisons betweentw oo rmor ecrossbre d groups,o r between a cross and one ormor e parental breeds.A t aminimum , data on first lactation milk yield, age at first calving, and firstcalvin g intervalwer erequired .' Such experiments are notoriously difficult to conduct. They are long-term, requiring a commitment of resources for 10 years or more. They require substantial numbers of animals for reasonable precision. Most often, the crosses are generated with imported semen, and the exotic or imported parental breed isno tpresen t inth e experiment.F 2 and back-cross generations are produced later than the Fl, and inevitably are subjected to different seasonal and management effects. Recording of production data may be irregular or incomplete. All of these factors make 40 interpretationo fth eresult sver ydifficult . The 46 data sets chosen for global analysis were those best structured inthes erespects .I n the overall analysis, a least squares model was fitted to estimate the effect of various degrees of Bos taurus genotype. The effect of heterosis was also included. In this analysis, breeds were simply classified as taurus or indicus. In a subsequent analysis, the differences between the three main Bos taurus breeds involved were also measured. The main results are presented inFigur e1 .

Fig. 1: Relative performance of Bos Taurus, Bos indicus and their crosses (Vertical .bar s represent standard errors).

(a)CALVIN G INTERVAL

—42 0

Proportion of Bos taurus 0/8 1/8 2/8 3/8 4/8 5/8 6/8 7/8 8/8 41 The results shown in Figure 1 indicate a nearly linear improvement in all traits up to 50%Bo s taurus inheritance. From this level onwards a slight increase in calving interval is observed, while no clear trend is seen in the othertraits .F 2 is inferiort oF li nal ltrait s studied. Estimates of the average genetic difference between Bos taurus and Bos indicususe d inthes eproject s are set out in Table 1. The first line gives the difference between the means of the two pure-bred groups from Figure 1, while estimates obtained by the multiple regression method using all eight genetics groups are set out in the second line. Standard errors are given in parentheses. The two sets of estimates are in close agreement, partly because they are based tosom e extent onth esam edata . The results suggest that Bos taurus calve about 1 year earlier than Bos indicus,produc e about 1,000 Kg more milk, havea onet otw omont h longer lactation, and are similar in calving interval.

Table1 . AdditiveGeneti cDifferenc eBetwee nBo sTauru s(P2 )'an dBo s Indicus(Fl )Cattl e

Methodo f Agea tfirs t Milk Lactation Calving estimation calving, yield, length, interval, (seetext ) (months) (kg) (days) (days)

P2- P I -12.9(1.2 ) 1101 (73) 52 (9) 0 (11) Regression -10.2(0.9 ) 1047 (60) 39 (6) 3 (8)

The overall non-linear effect of level of Bos taurus inheritance shown in Figure 1 indicates that heterosis is important in these crosses. Table 2 shows the estimates of heterosis, computed first as the difference between Fl and the mean of the two parental groups, and then by the multiple regressionmethod , using allgeneti c groups.Again , the agreement between the estimates obtained by the two methods is extremely good. Heterosis is substantial for all traits except lactation length. As a percent of mid-parent mean, it amount to -14%pe r age at first calving, +28% for milkyield , and -6%fo rcalvin g interval.Whe n milk yield is expressed per day of calving interval, heterosis is increased to+37 %o fmid-paren tmean . On the assumption of additive and dominance effects only, theperformanc e ofth eF 2shoul d be expected to behal f way between the Fl and mid-parent mean. The observed values for F2 in these data agree well with this expectation, except formil k yield, which wasmuc h lower than predicted from Fl and parental performance. This question needs further investigation, because it has implications for the breeding policy which should be followed beyond the first round of crossing.

42 Table2 . Heterosisi nBo sTauru sx Bo sIndicu sCrosse s

Methodo f Agea tfirs t Milk Lactation Calving estimation calving, yield, length, interval, (seetext ) (months) (kg) (days) (days)

Fl-(Pl+P2)/2 -5.6(0.8 ) 453(49 ) 7(6 ) -28(7 ) Regression -5.2(0.6 ) 449(40 ) 9(4 ) -30(5 )

In 14 of the data sets, more than one Bos taurus breed was included. Most frequently these were Friesian and Jersey, and in a few cases,Brow n Swiss.Thes e 14 data sets were collectively re-analysed to provide estimates of the differences between the Bos taurus breeds, as reflected in their Flprogeny .Th eresult sar eshow n inTabl e 3./

Table3 . Performanceo fFriesian ,Brow nSwis san dJerse yF lCrosse swit h BosIndicu s

Bostauru s Agea tfirs t Milk Lactation Calving breed calving, yield, length, interval, (months) (kg) (days) (days)

Friesian 33.4(0.3 ) 2165(27 ) 341(3 ) 429(3 ) BrownSwis s 35.3(0.5 ) 1921(55 ) 337(5 ) 435(6 ) Jersey 32.4(0.3 ) 1737(55 ) 326(3 ) 412(3 )

Jersey crosses were the youngest and Brown Swiss the oldest at first calving, both differing significantly from Friesian crosses. Friesian crosses had the highest and Jersey crosses the lowest milk yield, and again all differences were significant. Jerseys had significantly shorter calving intervals than the other two crosses. For lactation length, Jerseys had significantly shorter lactations than Friesian crosses.Th e ranking for yield was very consistent across data sets. Friesian crosses had the highest milk yield in all sets. Jersey crosses were the youngest at first calving inte n outo f thethirtee n setsi n which this trait was recorded, and had the shortest calving interval intwelv eou t of fourteensets . The choice between these breeds as the crossing source is very similar to that faced in temperate countries where these breeds are used inpur e form. Jerseys have advantages

43 in fertility andmil k composition. If beef,an d to a lesser extent work functions, are unimportant, these advantages should make Jersey crosses preferable. Where meat production, work, and milk volume rather than total solids arevalued ,Friesia ncrosse swoul d bepreferred . Breeding Strategies It is clear from these analyses that there is a substantial amountt ob egaine d fromcrossin gBo s indicust o Bos taurus dairy breeds for milk production in tropical countries. The two groups of breeds differ by about 100%i n milk production potential. To put this difference in context, we can note that current highly sophisticated selection schemes for milk production in Europe and North America are producing rates of genetic improvement of approximately 1%p.a .I nadditio nt oth e additive difference between the two breed groups, their first crosses profit from a heterosis effect of about 30%. The advantages of crossbreeding are, therefore, too big to ignore,'an d the reality istha tth edevelopin g dairy industry throughout the tropicalworl d isalmos tuniversall yusin gvariou sgrade so f crossing between local breeds and the developed Bos taurus dairybreeds . Cross-breeding canhav ethre eobjectives : - Breed replacement. - Formationo fa syntheti cbreed . -Maintenanc e of somefor mo frotationa l crossing system. The choice between these three objectives depends primarily on the balance between the additive difference between the two breeds involved on the one hand, and the extento fheterosi so nth eother .I fth eadditiv e difference is large and the heterosis effect small (as in crosses betweenNort hAmerica n Holstein and European Friesian), then the cross breeding programme will move towards breed replacement. If the additive difference is small, and the heterosiseffec tappreciabl e (asi ncrosse sbetwee nLandrac e arid Large White pigs) then a rotational cross-breeding programmeca nb euse d toexploi tth eheterosi s effectt oth e maximum. However, the maintenance of such a rotational system can be quite complex, and difficult to sustain in cattlepopulations ,particularl y indevelopin g countries.I n these circumstances, the establishment of a synthetic population has some advantages in terms of simple structures. It also has advantages in offering a balanced exploitation ofbot hth eadditiv ean dheterosi seffects . The choice between these strategies is perhaps best explained using the "Greek Temple" model (Figure 2),whic h shows the expected performance of a Bos indicus breed and its crosses with a dairy Bos taurus breed. The expectations are based on an average additive difference between the two types of about 70%, and a heterosis effect of about 40% (bothexpresse d asa percen t ofmid-paren t mean). 44 Fig. 2: The "Greek Temple" model showing the expected performance of a Bos indicus breed and its crosses with a dairy Bos taurus breed.

50 Bos taurus %

45 With these values, the Fl has the highest expected performance.Bac k crossest oth etw oparenta l breeds (Blan d B2) losehal f of theheterosi s effect as,doe sth e F2.Thes e three groups can be produced in the second generation of cross-breeding (bymatin g Fldam st o either of thepure-bre d parents or to Fl sires). However, it is not possible to stabilise a cattle breeding programme at any of these three points. Intersematin gwit h anyo fth egroup swil l lead toa synthetic population with that particular combination of genes from the two breeds. For synthetics formed from the F2, the expected performance is the same as for the F2. Synthetics formed from the two back-cross groups will have slightly reduced heterozygosity, and aparalie d reduction in heterosis effect. Synthetics can also be formed from other breed combinations. For example, the back-cross to Bos indicus (Bl) could be mated to the Bos taurus breed (P2)t o give a 5/8 Bos taurus combination. Interse mating among these could then produce a synthetic. When account is taken of the breed combination involved, and the amount of heterosis expected, the expected performance vo f any synthetic will be found to lie on the curved line labelled "synthetics" in Figure 2. With the additive and heterosis effects assumed here, it is clear that the expected performance of all synthetics from the F2u p toth epur e Bos taurusdoe sno t differgreatly . An alternative way of establishing a stable cross­ breeding system after the first generation is to practice systematic rotation between the two breeds. In each generation, pure-bred sires of one or other breed are used, thesir ebreed s alternating insuccessiv e generations.Afte r the system settles down, the offspring in alternate generations are either 33% or 67% Bos taurus. Adapting animal management simultaneously to these two genotypes might be difficult. In addition, adhering to the planned rotation of siresmigh t bedifficul t indevelopin g countries unless a highly efficient AI service is in place. With the additive and heterosis effects used here, the average performance of animals in such a rotational cross would be rather similar to that of synthetics with 75% Bos taurus genes. For these reasons,mos t taurus-indicus cross-breeding programmes formil kproductio n eventually concentrate onth e objective of creating asyntheti c breed. Two principal assumptions are involved in these deductions from the assembled experimental data. The first is that a model which takes account of additive and heterosis effects is adequate. There is some suggestion that, while this may be the case for other traits, it may not be sofo rth emos t important trait,mil k production. The principal evidence involved isth e frequent observation that the F2 production level is below expectation. Among the possible explanations is the idea that blocks of genes giving favourable epistatic effects in the parental breeds and the Fl may be broken up in the F2 and subsequent generations. This possibility clearly needs further investigation. The second assumption is that the experimental results used in constructing this model are relevant to the 46 production conditions inwhic h these genotypes are expected to perform. If that isno t the case,we could be faced with an interaction ofgenotyp ewit h environment.A s aver y broad generalization, one might expect that as the environment improves, the heterosis effect will become less important, while the additive difference may be enhanced. Conversely, in very poor environments, where resilience and resistance to various physiological and health challenges predominate, heterosis effects may be relatively more important and additive differences notver y pronounced. References Cunningham, E.P. & Syrstad, O. (1988), "Crossbreeding Bos indicus and Bos taurus formil k production in the Tropics". FAOAnima lproductio n andHealt h Paper68 .

47 Problemsassociate dwit hth etransfe r ofgeneti cmateria lfro m temperatet owar m Mediterranean regions:consequence s on theequilibratio n ofth eanima lproductio n systems

J.C.FLAMAN T

Unitéd eRecherche s sur lesSystème sAgraire se tl eDéveloppemen t CR.INR AToulous e BP273132 6Castanet-Tolosa n Cedex

Summary

The concepts of systems analysis are applied in order to enlighten the particular case of the introduction of North European breeds intowar m Mediterranean conditions.Considerin g the available genotypes in the Mediterranean region, the farmers have only the choice between local and self- regulated animals butwit h low-level, individual yield,an d imported, improved animals but which need an active equilibration of the whole system to protect them against the constraints of an adverse environment, and in particular against heat stress. The paper discusses the possibilities of obtaining genotypeswhic hwoul d possesssimultaneousl y highproductiv e potential and hardinesscapacity .

Résumé

Les concepts de l'analyse systémique sont ici mis en oeuvre en vue de donner un nouvel éclairage sur leca s de l'introduction de races Nord Européennes dans les conditions méditerranéennes chaudes. Si nous prenons en considération les types génétiques disponibles en Méditerranée, nous constatons que les éleveurs ont seulement le choix entre des animaux locaux, possédant une relative capacité d'autonomie, mais avec un niveau de production individuel faible, et des animaux améliorés mais dont l'élevage exige une équilibration active de tout le système afin de limiter les effets contraignants du milieu et en particulier de les protéger contre les stress climatiques.L e papier discute lespossibilité sd'obtentio n destype sgénétique sà lafoi s productifs et rustiques.

Introduction

The improvement of animal production in Mediterranean regions is currently achieved by crossing local breeds with North European breeds in contrast with the possibilities offered by pure breedgeneti c selection/Thispape r discussesth econsequence s of thischoic eb yapplyin gth e conceptso f systemsanalysi st oruminan t production systemsi nwar mMediterranea n conditions.

I - Thetransfe r ofgeneti cmateria l from temperate towar m Mediterranean regions

It is not easy to obtain a precise estimate of the annual flux of breeding animals between countries.Th e statisticso n thistyp eo f tradear e not readilyavailabl ei ncontras t tothos efo r milk,mea t or wool.Whil e it is true that the breeding organizations usually provide information about the export flux for whichthe y are responsible,th e statisticso f the importing countries are notver yconsisten twit h them, particularly when they include live animals imported for slaughter but which in fact are kept for breeding (FLAMANT, 1990). Nevertheless, it is not necessary to obtain a precise estimate of the physical amount of this trade in order to appreciate its genetic characteristics and consequences. Furthermore, despite the difficulties of obtaining reliable data, the facts are clear: the world trade of breeding animals mainly consists of flux from North European and American countries toward Mediterranean, South American, African and Asian countries. That means a transfer, into warm climatic conditions, of breeding animals and more generally of gene pools selected within temperate climaticconditions .

Various veterinary reports and technical studies usually provide information about the future of import breeding animals during the first months after their introduction. They all illustrate the lack

48 ofadaptabilit y ofNort h European breedst owar mMediterranea ncondition sbot hfo r sheepan dcattle .

Almost 50% of the imported Milchschaf rams die during the first year after their arrival in Greece from Germany (ZERVAS et al, 1975).Durin g the same first year, 28 to 60% of the Ile-de- France and Berrichonne du Cher rams imported to Sardinia from France, for use in an extensive programeo f heavylam bproductio n bycommercia l crossingwit h local ewes,di d not survive (CASU et al, 1981). The very well planned experiment carried out by ABOUL-ELA et al (1987), simoultaneously in Finland and in Egypt on half-sib Finnsheep ewes, enabled precise observation of the physiological responseswhic h occurred during the first year following their transfer to hot climatic conditionsan da nevaluatio n of their sensitivityt o heattemperatures .

In dairy cattle, the imports of improved genetic material, either bulls and cows,o r semen and even embryos, are motived by the need to improve the individual milk yield of the cows within a strategy for development of specialized units (FLAMANT, 1990).I n North African countries (Algeria, Morocco, Tunisia), the number of heifers imported from Europe during the period 1970-1985 is estimated at 3000 0t o5 000 0head sfo r each country.Bu t considering this continuous and costly effort, thetechnica l resultsar e relativelybad ,an dma yb eattibute d toth e insufficient adaptation of the import genotypes to thefield conditions .Th e actual percentage of improved pure breed dairy cows isonl y 15 to 25% of the total cattle livestock in these countries (approximatly 10000 0 animals in each country; BOURBOUZEe t al,1989) .

In fact the first criteria which should be considered for the choice of the genotype should not be the average individual milk or meat yield, but the replacement rate of the livestock estimated through the average number of calves produced bya cowdurin g its lifetime. It iscuriou s that very few studies on dairy cattle production, in pure bred or crossing programmes, take into account the lifetime production (GIBONe t al,1984) .

This bad adaptation is not only attributed to temperature problems. A lot of observations underline the negativeeffec t of feeding and grazing conditionsan d of disease,an d also the influence of the breeding season for the sheep and goat species.Bu t Iwoul d like to stress that despite the fact that this issue has been verywel l known for several decades, numerous and costly non-adapted breeds are againbein g exported from North European countries intoMediterranea n conditions.Thi s isth ecas e of the Milchschaf dairy sheep breed, for which the lack of tolerance to warm summer temperatures has been reported sinceth e end of the 19th century (FLAMANT and RICORDEAU, 1969).S o there isa need toconside r not onlyanima lperformance s evaluated witha limited number of criteria, but also the interactions of thegenotyp ewit hth echaracteristic so fth ewhol esystem .

II - Theconcept s ofsystem s analysis

1)Th econcep t ofa "managed technologicalsystem "

Figure 1 shows a simplified schema of a ruminant animal production system according to the conceptsexpresse d byGIBO N eta l (1988)an d toth e representation of thegenera l systempropose db y LEMOIGNE (1977). In this schema, the animal production system is considered as a "managed technologicalsystem" .

"Managed"mean stha t the systemi sunde r the control of an "operator", the farm manager who takes all decisions concerning the structure of the systemaccordin g to his goals ("strategical decision"), and concerning its daily, weekly or monthly functioning ("tactical decision"). These decisions are enlightened bymean so fth e "information system".

"Technological" because this system is a process for transforming plant material into animal products (live animals, milk, wool) while combining the "forage system" with the "herd management system". The animal products themselves may be used within the farm in a secondary manufacturing processbefor e their introduction intoth e commercial system.Severa loperation s mayb einvolve di nth e farm such as grouping the animals into homogeneous lots for sale, cheese processing, fleece grading andwoo lworking .

49 Figure 1. Representation of a ruminant animal production system considered as a "managed technologicalsystem" .

MANUFACTDBING AND MARKETING SYSTEM

Obviously in this schema, the animal material plays the role of the central motor of the technological process of transforming plant resources into animal products. Its characteristics and performances determine the characteristics andth e performances of thewhol e system.I nparticular ,w e mayconside r the consistency inth e choice of the animal material (thebree d within a species) with the technical objectives of the farmer for the whole system. FLAMANT and MORAND-FEHR (1988) identify three main contrasting objectives for animal production systems in the Mediterranean conditions: 1)developin g the useo f land resources,2 )increasin g the individualyiel do fanima lmaterial , 3) providing the market with specific products of high commercial value. The introduction of North European genetic material to Mediterranean farms is mainly advocated for attaining the second objective inMediterranea n farms.

2) The"equilibration " concept

The "equilibration" concept was first expressed by PIAGET (1975) in France and later taken into consideration and developed by LEMOIGNE (1977). Equilibration is considered as the basic property of all functioning opened systems. It is a process of self-regulation which enables the continuity and the productive function of a system, faced with variations in its environment or with a definitive changing of its environment, and with respect to its objectives. If this equilibration is not achieved,the n the systemeithe r disappearso r itsobjective s are notachieved .

If we attempt to apply the equilibration concept to the case of an animal production system in constraining conditions and if we consider more particularly the case of the introduction of exotic animals, the equilibration is not achieved if the animals die before breeding and producing, or if the reproduction rate isno t sufficient toinsur eth esubstainabilit y of the livestock,o r ifth e performances of the animalsar eobviousl y much lowertha n theleve lwhic hjustifie d their importation.

50 Generally it is admitted that this equilibration can only be obtained in animal production systemsb yusin gtw o alternativeapproaches : either the animalmateria l isadapte d to the constraintso f the general environment of thewhol e system,o r microenvironmenta l conditions are developed byth e farmer for protecting non-adapted animal material Finally and in this respect, the farmer has the choice between two decision-making approaches: one towards self-regulated animals, the other towardsa n "activeequilibration "o fth esystem .

Ill - Therespectiv einterest so fself-regulate d animalsan do factiv eequilibratio n byth efarme r

1)Th ehardines so fth eloca lMediterranea nbreed s

Referring to a systemic approach, hardiness may be taken to be the capacity of an animal to respond toth e permanent constraintso r toth e changesi nit scloses tenvironment ,independantl y of the permanent action of the farmer (VALLERAND, 1988).Variou s observations and results attest to the autonomy of local breeds in Mediterranean animal conditions: the building of daily feeding regimeb y grazing on range lands, the variation of the energetic body reserves faced with the alternation of abundance and shortages in the natural resources, the reproduction rate regarding the body condition and the future energetic needs. On this basis, the "PHILOETIOS" group (FLAMANT and MORAND-FEHR, 1988) considered the original traits of the local Mediterranean breeds to be a responset oth econstraint so fth eproductio n systemsi nwhic hthe yar einvolved .

In the caseo f thermic stress,eithe r hot in summer and in low-lying lands,o r cold in mountain pastures, several results demonstrate these adaptative traits in sheep particularly associated with fleece characteristics.VALL SORTI Zan d FOLCH PERA (1981)observe d that lowestincreas e of respiration rate in relation to ambient temperature occurred in Aragonese local sheep breed rather than in the exoticRomano vbree d during the summer monthsan d attributed thesedifference s to the black coloro f the Romanov animals. The role of the fleece in thermic regulation has also been demonstrated (VERMOREL et al, 1985) in the case of transhumant and outdoor systems in cold conditions, where the largestfleec e ofMerino styp ebreed sprovid eles ssensitivit yt ohars hwinters .

2) Examples ofactiv e equilibration

I call "active equilibration" all structural action carried out by the farmer operator, within the herd management system, for the purpose of protecting the animal material from the effects of an adverseenvironmen t Physiological studiesprovid eth e biologicalbasi sfo r an activeequilibratio n of the systems including exotic animal materialwhic h doesno t possess its own self-regulatory capacity .Thi s situation occurswhe n the farmer as manager of the system, makes the strategic choice of changing his animal material and when the new breed is chosen with priority given to its productive traits, milk or meat,independentl y ofit shardines scapacity .

A first equilibration action concerns the feeding regime itself, which has to be adjusted to the food requirements according to the potential level of production. High milk yield for instance, is not authorized byth e sole useo f natural pastures or of range lands.Example s from Yougoslavia,Portugal , Spain or Tunisia, demonstrate that the development of specialized dairy herds on the basis of local forage complemented by concentrate feeding, needs specific herd management and investments (TISSERAND,1989) .

However ifw econside r the Mediterranean climatic conditions the main direct constraint isth e ambient temperature during the dry summer season. For high productive dairy cows, active equilibration is needed in order to minimize the negative effects of temperature on intake rate, milk yieldan d reproduction rate.Thi sactiv eequilibratio n isachieve d in Israelb ycombinin g a distributiono f complete diet to avoid open-air grazingwit hventilate d buildings,a cooling effect by sprinkling on the animalso rwit hwate r evaporation onbuildin groofs .

For meat production, animal sheds seem sufficient for countering the climatic constraints both for cattle and sheep. For the import animals several observations demonstrate that it is necessary to avoid adding the negative effects of climatic stress to that of travel stress. For instance, for rams from

51 North European countries, CASU et al(1981) demonstrate that the loss percentage can be significantly lowered if a few simple conditions are respected such as the period of travel during intermediate seasons (not at all during the summer), and the respect of an adaptative time for feeding and building before the effective use of the ewes flock during the mating season under range conditions.

Artificial insemination can be considered a means of active equilibration in so far as it enables maintaining the males in a controlled environment if these animals are not able to survive under field herd and flock conditions (VALLS ORTIZ and PEREZ ALMERO, 1981).

3) Research on the compatibility of self-regulation capacity with high individual yield

a - Technological packages

In fact, under constraining conditions, the equilibration of animal production systems has a cost if we admit that there are only two alternative approaches: either the farmer keeps his local and self- regulated animals but without hope of increasing their productivity by means of individual yields, or he introduces exotic and productive animals while having to create an active equilibration of the system. A simple example of such a cost can be given by the consequences of using specialized meat rams for crossing with local ewes, which needs, as mentioned before (VALLS ORTIZ and PEREZ ALMERO, 1981), the organization of a programme of artificial insemination, associated -with oestrous synchronization within the flocks.

The particular case of goat production in Corsica, is a good example of the attitudes of farmers to the technical solutions offered. In that situation (CRISTOFINI et al., 1978) observed that the modernization of the production system is considered as a whole in the framework of what they call a "practices system" ("système de pratiques"):cultivate d forage, specialized housing, veterinary action, etc, were only applied to herds including Saanen or Alpine exotic goats and not by farmers who kept local Corsican breeds for which the practices were more organized towards the extensive use of grazing resources. The example of dairy cattle in Israel (KISLEV et al., 1984) demonstrates that it involved not only the choice of an improved genetic material but also the transformation of the whole system, and even the building of a totally new system, a "technological package", associating a lot of structural investments, and of techniques andworkin g practices into livestock management

b - Improved and adapted animals

At this stage it is interesting to explore whether there are other possible approaches and in particular whether it is possible to achieve modernized animal production systems, using self-regulated animals which could tolerate a low level of active equilibration by farmers. Several questions can be considered according to the specific problem of heat tolerance: is there a physiological compatibility or opposition between high production level and warm conditions ? Is a selection on productive traits under warm conditions feasible ? Do we know of any highly productive local breeds in the Mediterranean region? Have ifferences between North Euroean breeds been observed for their temperature regulation? Is there evidence of a statistical genetic-environment interaction involving heat tolerance?

The answers to all these questions are not available, but certain facts demonstrate the possibility of attaining high productivity under warm Mediterranean conditions. The first of these is the existence in these countries of local breeds producing higher milk and dry matter yields (Chios sheep breed in Greece, Riverine buffalo in Egypt) or prolificacy rate (Demmane breed in Morocco) than the imported exotic breed in the same environment

Bearing in mind that higher food intake and performances increase internal heat production, it is however interesting to look at the possible differences betwen breeds for heat tolerance, measured by the evaporating rate or the rectal temperature. Through such a test carried out under standard conditions on French cattle breeds, HALIPRE and BIBE (1971) observed a best heat tolerance of the local mountain breeds (Gascogne and Aubrac), followed by meat breeds (Blonde d'Aquitane and Charolais), and a lower tolerance for dairy cattle breeds (Holstein and Normande). This type of result

52 can provide arguments for choosing both adapted as well as improved breeds for a Mediterranean environment

Concerning the evidence of genotype-environment interactions, planned, large scale experiments involving NorthEuropea n and Mediterranean regionshav eno tye tbee n carriedou t From a reviewo f resultsobtaine d in aver ywid evariet yo ftropica l environmentswit hF l andhack-crosse s of native and Friesian-Jersey cattle,SYRSTA D (1990) concludes that there isn o evidence of genotype- environment interaction on milkyiel d per lactation.Bu t I agree with the author that the results might bedifferen t ifth e studiesinclude dviabilit ytraits :a sI mentioned before, thenumbe r ofcatving san d the lifetime milkyiel dwoul dprobabl yb emor epertinen t criteria.

Considerations on temperature tolerance in the Mediterranean environment have also to be combined with the problem of the breeding season for sheep and goat production. In fact the out- seasonbreedin g capacityo fth e localMediterranea n breeds enablethe mt olimi tthei r productive period during winter and spring, when the heat stress is not combined with higher thermogenesis by the animals, in contrast to North European ewesfor whic h the lambingsca n occur too late in the season with respect to temperatures and grazing availability (ZERVAS et al, 1975)). An example of this feature isals ogive n in Spain byFOLC H andROC A (1981)wh oobserve d the lowest sexualactivit yo f imported meatram si ncontras t toth e localRas aAragones e duringth e springmatin g season

Conclusions

Clearlyth e objective of thispape r isno t toprovid ene wresult s on the issue of the introduction of exotic breeds in warm Mediterranean conditions. All the information reported here is well known and has been for several decades.It s goalwa sonl y to propose a global approach to these problemsb y using the concepts of systems analysis. Obviously the evolution and transformation of animal production in Mediterranean regions have to be a compromise between two alternative approaches: either keeping the local adapted breeds but with a low productive level, or introducing exotic breeds with a high potential level but finally with bad technical results if new and sometime costly technological packages are not adopted. It seems difficult for an individual farmer to escape the consequences of this opposition, even if there are theoretical possibilities of screening the European breeds as to their heat tolerance and if the selection of local breeds proves to be feasible (Cf. Lacaunc breed inFrance) .I n factw ear eobservin g acontinuou s flux of exoticbreed san da lot of experimentsi n crossingthe mwit h localbreeds ,eve n inth e casewher e localbreed s havea high productivity level.An d the effort to select local breeds bymean s of recording programmes on farms is clearly insufficient, in contrast to the efficiency of North European and American programmes carried out under more and more artificial conditions. Finally all of these evolutions induce an increasing stratification among farmers with respect to regarding the modernity/tradition problem, given the financial possibilities of improvingthei r production system.

References

ABOUL-ELA M.B., ABOUL-NAGA A.M., SHALABY T.H., MAIJALA K., 1987. Physiological response to climatic changes in Finnish Landrace ewesimporte d to Egypt and their half- sibsraise d inFinland .Livestoc kProductio n Science, 17,179-185. BOURBOUZE A., CHOUCHEN A., EDDEBBARH A., PLUVINAGE J. YAKHLEF H., 1989.Analys e comparée de l'effet despolitique s laitières sur les structures de production et de collecte dans les pays du Maghreb. In "Le lait dans la région méditerranéenne", Options Méditerranéennes, SérieSéminaires ,N °6 ,247-258 . CASU S. SANNA A., CAPPAI P., RUDA G., 1981; Problèmes liés à l'introduction et l'atilisation de béliers de race à viande pour le croisement industriel en Sardaigne. In "Le croisement industrielovi ne n Méditerranée", OptionsMéditerranéennes ,Séri eEtudes , 1981-III, 113-122 CRISTOFINIB.,DEFFONTAINE SJ.P. ,RAICHO N G, DE VERNEUIL B., 1978.Pratique s d'élevage en Castagnicia. Exploration d'un milieu naturel et social en Corse. Etudes Rurales, 71-72, 89-109.

53 FLAMANT J.C., 1990. Les systèmes d'élevage méditerranéens dans leurs rapports aux systèmes céréaliers: transformations et diversité. Symposium "L'élevage dans les systèmes céréaliers méditerranéens",7-1 0 octobre, 14 pages. FLAMANTJ.C. , 1991.Internationa l exchange of genetic material. InMAÜAL A K."Geneti c resourceso fpig ,shee pan dgoat" ,Worl dAnima lScience ,Vo l 12,357-363. FLAMANT J.C., MORAND-FEHR P., 1989. Introduction au Symposium Philoetios: le matériel animal dansse s rapportsave c les systèmes de production: conséquences pour sonévaluation . In "L'évaluation des ovins et caprins méditerranéens", Rapport des Commissions Européennes, EUR 11893FR.EN ,57 8 pages. FLAMANTJ.C. ,RICORDEA U G., 1969.Croisement s entre racesovine s Préalpes duSu de t Frisonne (Ostfriesisches Milchschaf). I - La brebis laitière de Frise Orientale. Elevage en racepure . Utilisatione ncroisemen tAnnale sd eZootechnie , 18,107-130 FOLCHJ. , ROCA M., 1981.Importanc ed e l'activitésexuell e dumâl edan sl e développement du croisement industriel en Espagne. In "Le croisement industriel ovin en Méditerranée", Options Méditerranéennes,Séri eEtudes ,1981-HI , 135-142 GIBONAnnick , CASABLANCA F., FLAMANTJ.C. , 1984.Th e implication of reproduction in relations between farmers, flock or herd, and the food resources of the farm territory within the animal husbandry systems. In ORTAVANT R.an dSCHINDLE R H., "The reproductive potential of cattle and sheep",Join t Israeli-French Symposium, Rehovot (Israël), 21-23 February, 369-391. (Les Colloquesd e1'INR AN °27 ,INR APubl . Ed.) GIBON Annick,ROU X M., VALLERAND F., 1988.Eleveur , troupeau et espace fourrager: contribution à l'approche globale des systèmes d'élevage. Etudes et Recherches sur les Systèmes Agrairese tl eDéveloppement ,N °11,14 4pages .INR APublication s GONZALEZ LOPEZ J., ESPEJO DIAZ M., BRICE G., JARDON C, 1981.Inséminatio n artificielle debrebi save cd el asemenc efraîch e récoltéeà grand edistanc ed ulie ud'insémination . In "Le croisement industriel ovin en Méditerranée", Options méditerranéennes, Série Etudes, 1981-III, 129- 134 HALIPREA , BIBEB. , 1971.Amélioratio nde sbovin ssou sle stropiques .Généralité s etchoi x desraces .Documen t polycop.Statio nd eGénétiqu equantitativ ee tappliquée ,INRA ,2 9page s KIVLEV M., MEISEL S., AMIR S., 1984. Dairy industry in Israël. In NESTEL B., "Developmento fanima lproductio nsystems" , WorldAnima lScienc eA2,297-309 ,Elsevie rEdi t LEMOIGNE J.L., 1977. La théorie du système général. Théorie de la modélisation. Presses Universitairesd eFrance ,32 0 pages. PLAGET, 1975.L'équilibratio n des structures cognitives, problème central du développement PressesUniversitaire sd eFrance ,18 8 pages. SYRSTAD O., 1990.Dair y cattlecrossbreedin g in the tropics: the importance of genotype X environmentinteraction .Livestoc k ProductionScience ,24,109-118 . TISSERANDJ.L. , 1989.L elai te n régionméditerranéenne . Actes duColloqu e de Rabat,25 - 27octobr e 1988.Option sMéditerranéennes ,Séri eA :Séminaire sMéditeranéens ,N°6 ,31 9 pages. VALLERAND F., 1988. La rusticité: niveaux et méthodes d'approche en milieu réel In HUBERTB .an dGIRAUL TN. ,"D el atouff e d'herbea upaysage" , 85-101,Séminair eVien s(France) , 13-14Janvie r 1983,INRA-SA D Paris. VALLS ORTIZ M.,PERE Z ALMEROJ.L. , 1981.Le s systèmesd ediffusio n desbélier se tl e développement ducroisemen t industriel dansl a région de Zaragoza.I n "Lecroisemen t industrielovi n enMéditerranée" .Option sMéditerranéennes ,Séri eEtudes ,N ° 1981-III, 123-128. VERMOREL M., HOCQUETTE J.F., BOUIX J., 1985. Recherches sur les aptitudes à la transhumanced edifférente s racesovines :résistanc e auxintempéries .Journée s del aRecherch e Ovine etCaprine ,292-30 6 ZERVAS N., BOYAZOGLU J.G., KALAISSAKIS P., PAPADIMITRIOU T., FLAMANT J.C., 1975. Comparaison des races ovines Chios et Frisonne avec leurs croisements en Grèce continentale.Ann .Géné t SélAnim.,7(3) , 277-291.

54 SELECTIONAN D BREEDING STRATEGIES FOR PRODUCTION IN WARM CLIMATES

K.J . Peters Institute forAnima l Production,Technica l University Berlin,Lentzealle e 75,D-100 0Berli n 33

Summary Breed improvement strategies aima tprovidin g suitable animals for sustained production undergreatl y variable production conditions.Heterogenit y of ecological,economi ­ cal, infrastructural and cultural environments inman ywar m climate countries demand carefull analysis ofneed s foran d scope of performance improvement.Productio n objections are morevariabl e inles s intensiv and less spezialized systems and require carefulassessment . Evidence fromdair yproductio n data suggesta ninsuf ­ ficient consideration of local stock and alac k ofcompre ­ hensiveperformanc e data fromcrossbreedin g programs to estimatemil k production efficiency. Largeaverag egeneti c differences betweenbo stauru sdair ybreed san dmos tbo s indicus breeds indigenous towar m climates can effectively beutilize d through simplebreedin g systems.Breedin g schemes toexploi t heterosis aredifficul t toimplement . Only simpleon-far mperformanc e testing schemes and open nucleus breeding schemes arelikel y tob e successful in smallholder dairy systems.Ther e isa nacut enee d forfur ­ therdevelopmen t of appropriate on-farm performance test and improvementschemes .

Introducton For centuries domestic animalshav eperforme d and sur­ vived under ecological and.economicproductio n conditions of tropical regions.Animal s servenumerou s functions in traditional subsistence systems and arebre d and selected for sustainableperformanc e atlo wrisk . Itha sbee nre ­ cognized thatreproductiv e andgrowt h traits arewel lde ­ veloped in local animalswhic h onlyunde rver y favourable conditions justifies theintroductio n of specialized,hig h performing breeds. Since improvement ofmil k performance hasbee n tried for abouta centor y through introduction of exoticmil kgene san d tomodif y orreplac e local genotypes inman ywar m climate countries,thi spape rwant s tocon ­ centrate onbreedin g strategies fordair yproduction.Ther e isa long standing believe that selection in local cattle isto o slowan d complicated tomee t the fast increasingde ­ mand forurba n populations (McDowell ,1988) .A second pre­ misewa s theassumptio n thateconomical ,infrastructura l andmanagemen t improvementwoul d soonpermi t amor einten ­ siveproductio n process.Bu ta sBondo c eta l (1989)poin t

55 out, increasing theproductiv e efficiency of dairy cattle in smallholder systemsremain s an important challengean d highly specialised dairy cattle improvement systems as practised indevelope d countriesma yno tb e biologically and economically suitable forwar m climates indevelopin g countries. Lessons from Europeanhistor y ofbree d development can tell that thenee d toimprov eperformanc e isdrive nb ycon ­ sumeran dmarke t forcesbu tar eonl yrealize d inth eeven t of changes inth eeconomi c and institutional environment to allow farmers tohav e full control overthei rresources ,t o purchase production inputs and other tohav e access toser ­ vicesreducin g theproductio n risk (Winkel,1984) . Theob ­ jective of this paper ist odiscus sbreedin g and selection strategies inth e contexto f achieving sustainable breeding and production.

Thenee d forperformanc e improvement Thegrowin ghuma npopulatio n inman ywar m climate countries and the increasing urban.purchasin gpowe rha s caused dairydeman d toexpand . FAO'(1986,zite d inBondo c et al., 1989)report s that several high income,relativel y urbanised developing countries have succeded inestab ­ lishing specialized dairyproductio n enterprises through subsidising domesticproduction . Indevelopin g countries withpredominan t ruraldair yproductio n andrisin g urban dairy demand prospects forincreasin g domestic dairy pro­ duction from integrated smallholder farming systems largely depend not only ondair y importpricin g policies.Effi ­ ciency ofmarketin g systems,processin g options,acces s to inputs and services,an d theabilit y toincreas e the effi­ ciency of resourcemanagemen t inth eproductio n system (Peters, 1989).

Thedair y production systeman d breeding objectives Themajorit y of cattle inwar m climates arekep ti n smallholder farms (McDowell ,1981 ;Peters ,1989) . Milk production isa ke y function,bu tmanur eproduction ,us eo f draught power,capita l investment andris k aversion are also objectives forkeepin gcattle . Level ofperformanc e isrelate d toexpecte d functions, available resources and ecological productionconditions . Production systems areno t static butCorrelat ewit hfac ­ tors of the social,economic ,institutiona l andtechnologi ­ cal environment.An y changes inproductio n intensity and management of the systemma yno tb e sustainableunles s respective changes of theproductio n environment arecon ­ ducive to systemdevelopment . The effect oftemperatu ran d humidity,rainfal l dis­ tribution,seasonalit y of feed supply,an ddiseas e pressure onanima l performance canb emanipulate d through husbandry technics.However ,reducin g environmental stress ondair y cowsrequire s aconsiderabl e level ofexterna l inputs ata 56 high cost,ofte n economically notappropriat e and sustain­ able. Communal landus erestrainin g amor eeffectiv e forage production concept isa majo rproblem . Thedependenc y on external inputs (concentrate,drugs) , as itoccur s after introduction of exoticgenes ,i sanothe r constraint in countrieswit h lessdevelope d feed supply infrastructures andwit h foreignexchang eproblems .An y increase inproduc ­ tion intensity inassociatio nwit h breed improvement pro­ grammes changes cost-benefit ratiosan d increasesproduc ­ tionris k and onemus t askth equestio nwhethe r farms can sustain such a jumpi nintensity . If further complicated by needs tomaintai nmil k collecting andprocessin g schemes which function efficiently onlywit hgoo d road infrastruc­ tures orwit h reliabledecentralize d dairymarketin g and service schemes,man y farmersma y notb eabl et oretai n participation inimprovemen tprogramme s (Waters-Bayer, 1988;Gryseel s andBoodt ,1986) . Onlywit h comprehensive analysis of theproductio n systems and itsrelate d sectors will itb epossibl e toasses s thescop e for changing the situations thatar e tob eth etarget s ofbree d improvement programmes inwhic h breeding objective isno t lactation yield but overall performance of herd efficiency overtime .

Organization ofbreedin g schemes Production systems inwar m climate countries areles s uniform than intemperat e countries duet odifference s in infrastructural development,acces s toinput s andmarkets , communication and technology. Thesedifference s in farm development call fora flexibl ebreedin g policy providing variable performance levels formajo r farm situations ina country. Breeding societies,A I stations and services,perfor ­ mance testing and sireevaluatio n schemeshav e allha da major share inimprovin g milk production indevelope d coun­ tries.Onl y aver y limited number of countries inwar m cli­ mates have sucha functional breed improvement organiza­ tion.Les s demanding breed improvementmethod s need tob e tested and implemented to serve smallholder systems.Breed ­ erAssociations ,Villag e bull schemes andBreedin g stations preferablymanage d by theBreede rAssociatio nma y fulfill major functions to initiâtbree d improvement schemes.

Evaluation of breeds and breeding systems Importance of local breeds Environmental stress,diseas e challenges and seasonal malnutrition puta hig hdeman d onth eproductiv eadaptabi ­ lity of indigenous animals andma ymas k theirgeneti cpo ­ tential undermor e favourableenvironments . Survival and fitness traits areo fparticula r importance under lessin ­ tensive production conditions and in less favourableecolo ­ gical regions.M cDowel l (1988)point s out,tha t therei s

57 considerable evidence to showtha tmos t local cattlewil l respond efficiently toimprove d feedingan dmanagement .Fo r example,attempt s to improve localbreed sthroug h selection have successfully been implemented in Indiawit h Sahiwal,a breed,whic h isno w increasinglyuse d inAfric a (Trailan d Gregory, 1988). Recently published results ondair ymerit s ofKenan a cattle inSuda nd oals odemonstrat e considerable performance abilitywit h average lactationyield s of 1500 kg and peakperformance s at450 0k g (Saeed et al., 1987). Most evaluation schemes havebee nconfine d torelativel y small populations kepto n stationswit h only limited scope for selection (Peters andThorpe , 1988). Success inim ­ provement of localbreed sha sbee nachieve dwit hwel lde ­ fined breeding objectives anda nefficien tbree d im­ provement organisation (AI,performanc e testing,progen y testing and sireevaluation )a sdemonstrate d byMey nan d Wilkins (1974)fo rKeny a andNagarcenka r (1982)fo rIndia , and iso f special importance forregion swit h high enzootic diseasepressure .However ,elaborat ebree d improvementor ­ ganizations arever y costly andrequir eheav ysubsidies ; simpler schemes have tob edevelope d forevaluatin g local genetic resources.

Useo f exotic breeds The largegeneti cdifference s indair y performance betweenbreed s indigenous towar m climates and exotic breeds selected formil k production,estimate d at 1047k g per lactation (Cunningham and Syrstad, 1987,cite db yBon - doc et al, 1989), has led toa n increased useo f highper ­ forming dairy breeds foreithe r replacing local stock or for crossbreeding. Purebre dbo stauru skep ti nwar m envi­ ronments of developing countries have shownperformanc ede ­ pressions of upt o 40pe r cent (Petersan d Selvarajah, 1977; Taneja and Bhat,1986) . Bos taurusrequir e about 10 kgTD N perday ,doubl e theamoun t than indigenous breeds (McDowell ,1988) . The inability toprovid eadequat enutri ­ tion,appropriat e hygienemanagemen t and control ofenzoo ­ tic diseases hasgenerall y lead tohig hvariation s in performance,reproductio n failures,hig hmortalit y and shortproductiv e lifespan (Nagarcenkar,1982 ;Vaccaro , 1990, Katpatal, 1977). Theus eo fexoti cdair ybreed s forcrossbreedin g has beenwidel y accepted and aimsa tcombinin g the superior performanceo f specialized dairybreeds -wit h the superior adaptability of local stock.Th edelicat ebalanc e between genetic performance ability and adaptability isdetermine d by thedegre e of exotic inheritance. Syrstad (1985)ha s analysed performance dateo ftropica l dairy cattle improved by crossbreeding,upgradin g andrepea t crossing usingre ­ ports oncrossbreedin g in 12differen t countries over the last 20years .Mea nmil kyield s suggesta nearl y linearin ­ crease inproductivit y upt o 1/2 exotic inheritance (Table1) .

58 Table 1:Leas t squaresmean so fvariou s genetic groups InBo stauru s& Bo sIndlcu s crossbreeding mod. after Syrstad (1985)

Genetic Agea t Lactation Calving Overall** group* first calving(mo ) mi Ikyiel d(kg ) interval (days) value(DM )

Xx X2 X3

L 0 42.2 1055 448 -753 1/8 41.1 1434 440 -447 2/8 37.2 1507 442 -214 3/8 36.3 1590 432 -8 9 F, 4/8 32.0 2028 423 415 5/8 33.7 2019 423 325 6/8 34.0 2065 444 275 7/8 34.8 1977 450 164 8/8 32.0 2176 463 384

Fa.F3 9 34.9 1573 446 - 71

Average 35.8 1742 441 f * proport ion of indigenous/exotici nheritance

**overal l va lue --5 0(X ,- 35.8) 4 •0. 6 (X,t - 1742 )- 3 (X 3 -441 )

Furtherupgradin g doesno tincreas emil k yield and has negativeeffect s onag ea tfirs tcalving ,calvin g interval, survivability and herd life (Syrstad,1985 ;Vaccaro , 1990). The importance of genotype xenvironmen t interactionwer e estimated by Syrstad (1990)usin g reports on crossbreeding experiments inAsia ,Afric a andLati nAmerica .N o genotype x environment interactions inmil kyiel dwer eestimate d for Fi and Bi crosses or forJerse y andFrisia n crosses.Thes e finding arebase d on lactationyield s only andma y notre ­ flectth eoveral l dairyproductio n efficiency incorporating survival rate,calvin g interval,replacemen t needs,lacta ­ tionyiel d andmil kyiel d peruni tbod yweigh t tob emain ­ tained inth eherd . There is a lack of comprehensive field performance testdat a able tocombin emil k performance andher d life timeunde r farmers condition.T o fullyasses s thedair y merit of crossbreds ofdifferen t level ofexoti cinheri ­ tance and toprovid ea solidbas e forpolic ydecisions , field test comparing localbreed swit hdifferen t crossbred genotypes arenecessar y.

Breeding systems Choiceo fbreedin g system isrelate d toth e importance of additive geneeffects ,th egeneti c differences between local and temperate breeds,th erelativ evalu eo f heterosis and theoptima l level of inheritance (Simon, 1982). The technical consequences and organizational prerequisites of different breeding systems need tob ecarefull y considered beforedesignin g breedingprogrammes .

59 Scheineswhic h requiremaintenanc e of several exotic breeds and theus e of alternate sirebreed sma y beto o costly and difficult toorganise . Inmos t countries theor ­ ganisational base formaintainin g crossbreeding system is weak. Simpleprogramme swhic h initially dono trel y onpro ­ geny tested sires and artifical insemination but still uti­ lizebree d differences inperformanc e areprefered .

Evaluation of comparative field performance testsan d improvement schemes After reviewing experiences gained from cattleim ­ provement schemes inwar mclimate so fdevelopin g countries McDowel 1 (1988)conclude s thatgreate r care isrequire d in designing breeding policies andprograms .Mai n issues tob e considered inbree d improvement strategies are • the implementation ofon-far mperformanc e tests.,fo r evaluating thedair ymeri t of local stock and for testing crossbred dairy cattleunde rproductio ncondi ­ tions • theus e of animal breeding stations forbree d potential assessment,testin g ofmanagemen t techniques,a sa central breeding station forproducin g crossbred bulls ora sa bas e fornucleu sbreedin g schemes • establishment of astron g linkagebetwee n cattlefar ­ mers and abreedin g program through formationo f group breeding schemes orbreede r associations and open nucleus breeding schemes. On-farm performance testing schemes for smallholder cattle systems following traditional,les s controlledmana ­ gement practies need toappl y simpleprocedure s toiniti ­ ally identify phenotypically superior animals.Thes e pro­ ceduresma y include farmers opinion abouthi s animals and hisknowledg e aboutperformanc e histories.Wit h a sample sizeo f 1200 cowsan d 120sire s tob eteste d over at least two lactations and distributed overa tleas t 10village s it ispossibl e toestablis h abas elin eperformanc e databan k toestimat e the influence of systematic effects,firs tpo ­ pulation parameter and toran k animals according toper ­ formance (Bruns,1989) . Thereafter,on-far m performance testsma y require simpler procedures.I f farmers canbene ­ fit fromparticipatin g in suchtestin g schemes through direct feedback and adviseo nmanagemen t techniques iti s feasable topartl y establish afarme rbase d recording pro­ gram aspractise d in Zimbabwe.Unde r those conditions it should bepossibl e to implement acomparativ e breeding ex­ periment producing and evaluating purebreed locals,Fx ,an d bothbackcros sgenotyp s as suggested byBrun s (1989).

60 Table2 :Desig nfo ra comparativ e genotype evaluationo nfar m (Bruns, 1989)

Village genotyp N N N No. female lactation sires

1- 3 Lx L (purebred) 600 1200 30 4 -6 Ax L (Fx) 600 1200 30 7- 9 Lx A L (BL) 600 1200 30 10- 1 2 Ax A L (BA) 600 1200 30

Onlywit h on-farmperformanc e testing itwil l bepos ­ sible to contribute togeneti c resource evaluations and to establish anope nnucleu s breeding schemes asdiscribe d by Cunningham (1980) (cited inBondo c et al, 1989). More elaborate schemes for sireprogen y testingre ­ quiring alarg e activebreedin g populationwit hmil k recording andA I areno tcompatibl ewit h the level of com- municaton,infrastructur e andproductio n intensity inmos t warm climatedair ysystems .

Conclusion Breeding and selection strategies appropriate toth e level of development inmos tdevelopin g countriesmus tcon ­ sider fivemajo raspects . a)Th evariabilit yo f environments andproductio nconditi ­ onswithi n and between countriesmak e itimperativ e to carefully analyse thenee d and scope forperformanc e im­ provement and the importance of factors limiting production sucha sdiseas e challenge,marke t and service infrastruc­ ture,communicatio n levelan d technology availability. b)Dair y production systemsvar y inproductio n intensités, access toinfrastructur e andmarkets .Differen t situations may lead todifferen t breeding objectives andma y require different types of cattle.A regionally organised breeding programma y beneede d toprovid ebreedin g material varying in inheritance for sizean dperformance . c)Th e search forth emos t suitablebreeds, breedin g sy­ stems and level of exotic inheritance canpartl y bebase d onth egloba l information base if carefully related to spe­ cific conditions of individual countries.Futur e cross­ breeding schemesmus tb e subject toa contemporar y compari­ sono f all genotypes underrealisti cproductio nconditions . The inclusion of local stockmanage d under conditions com­ parable to thoseprovide d forcrossbred sma y provide amor e meaningful base forassessin g theproductiv e adaptability and production efficiency of indigenousbreeds .

61 d)Breedin g programswhic h initially rely on theimporta ­ tiono f superior genes soonhav et oestablis h anorganisa ­ tional base formaintainin g orimprovin g performanceo f crossbred genotypes of thene wpopulatio n through on-farm performance testing and sireselection . e)Simpl e field performance tests and opennucleu s breeding schemes if operated throughBreeder sAssociatio n orgrou p breeding schemes areon e solution forth eevaluatio n oflo ­ calbreeds ,fo r thecompariso n ofdifferen t genotypes,an d for the improvement of performance levels indair yproduc ­ tion systems.Suc h schemesnee durgen tdevelopment .

References Bondoc,O.L. ,C . Smith andJ.P .Gibson ,1989 .A reviewo f breeding strategies forgeneti c improvement of dairy cattle indevelopin g countries.Anima lBreedin gAb ­ stracts,Vol .57 ,No .10 :819-829 . Bruns,E. ,1989 .Bree d improvement programmes.Unpubl .con ­ tribution toth etrainin g course "On-farm Livestock performance testing",29.5.-9-.6.89 ,ILCA ,Addi sAbeba , Ethiopia. Greyseels,G . andK .d eBoodt ,1986 .Integratio no f crossbred cowso n smallholder farms inth eDebr e Zeit area of the Ethiopian highlands.Mimeo , ILCA,Addi s Abeba,Ethiopia . Katpatal,B.G. , 1977.Dair y cattle crossbreeding inIndia . 2.Th e results of theAll-Indi a Coordinated Research on cattle.Worl dAnima lReview ,23 :2-9 . Madalena,F.E. , 1981.Crossbreedin g strategies fordair y cattle inBrazil .Worl dAnima l Review,38 :23-30 . McDowell ,R.E. ,1981 .Limitation s fordair y production in developing countries.Journa l ofAnima l Science,64 : 2463-2475. Mc Dowell,R.E. ,1988 .Strategie s forgeneti c improvement of cattle inwar m climates,p 61-73. IARproceedings , Second National Livestock Improvement conference,24. - 26. Feb.,Addi sAbeba ,Ethiopia . Meyn,K . and J. V.Wilkins ,1974 .Breedin g formil k in Kenya,wit hparticula r reference toth e Sahiwal Stud. World Animal Review,11 :24-30 . Nagarcenkar,R. , 1982.Breedin g fordair y production inth e tropics. 2ndWorl d Congresso nGenetic s Applied to Livestock Production,5 :414-438 . Peters,K.J . and T. Selvarajah,1977 .Breedin g formil k in Malaysia.Mai .Appl . Biol.,Vol .'6 ,2 :243-254 . Peters,K.J . andW .Thorpe ,1988 .Curren t status and trends inon-far m performance testing of cattle and sheep in Africa. Proc. IllrdWorl d Congress Sheepan dBee f Cattle Breeding,1 :275-293 . Peters,K.J. , 1989.Smallholde r dairyproductio n inAfric a Southo f theSahara .Pape rpresente d atth e 4thInter ­ national DLG-Symposium "ModernCattl e Production", Nov. 24.-26.,Giessen ,F.R . ofGermany , 28pp .

62 Saeed,A.M. ,P.N . Ward,D .Light ,J.W . Durkinan dR.T . Wil­ son, 1987.Characterisatio n ofKenan a cattlea tU m Banein,Sudan .ILC AResearc h ReportNo .11 ,Addi s Abeba,Ethiopia . Simon,D. , 1982.Nutzun g genetischerRessource n durchange ­ paßte Zuchtprogramme,DS EBericht , Expertengespräch "Erhaltung genetischer Ressourcen inde r Tierproduk­ tionde r Tropenun d Subtropen",Feldafing : 50-54. Syrstad,0. , 1985.Dair ymerit s ofvariou s Bostauru s xbo s indicus crosses,p 11.Commissio n onAnima lGenetics , Session II:Strategie s forgeneti c improvement intro ­ pical and subtropical conditions ofdevelopin g coun­ tries. 36thAnnua lMeetin g of the EAAP,Kallithea , 30.9.-3.1.1985. Syrstad,0. , 1990.Dair y cattle crossbreeding inth e tro­ pics: Th e importance ofGenotyp e xEnvironmen t In­ teraction.Livestoc k Production Science,24 :109-118 . Taneja,V.K . and P.N. Bhat,1986 .Mil k andbee f production intropica l environments. 3rdWorl d Congress onGene ­ ticsApplie d toLivestoc k Production, 9: 73-91. Trail,J.CM . andK.E .Gregory , 1981.Sahiwa l cattle:a n evaluation of thepotentia l contribution tomi^ k and beef production inAfrica . ILCAMonogr .No .3 ,ILCA , AddisAbeba ,Ethiopia . Vaccaro,L.P. , 1990.Surviva l of Europeandair y breeds and their crosseswit h zebus inth etropics .Anima l Breed­ ingAbstracts ,Vol .58 ,No .6 :475-494 . Waters-Bayer,A. , 1988.Dairyin g by settled Fulaniagro - pastoralists inCentra lNigeria .Farmin g systems and resource economics inth etropics ,Vol .4 ,VAU KVerla g Kiel. Winkel,H. , 1984.Entwicklun g im 19.un d 20.Jahrhundert . InComberg ,G. , 1984:Di edeutsch e Tierzucht im19 . und 20.Jahrhundert ,Verla g EugenUlmer ,Stuttgart .

63 FEEDING STRATEGY FOR ANIMAL PRODUCTION INVAR N CLIMATES

J.L. Tisserand Laboratoire de recherches de laChair e de Zootechnie del'Ecol e Nationale Supérieure des Sciences Agronomiques Appliquées. 26, Bd.Docteu r Petitjean. 21000Dijon .Franc e

Summary This paper reason the feeding strategy for animal production in warm and arid regions by dealing successively with the digestive and metabolic phenomena considered, the consequences for the reasoning of a diet, the means to enhance the values of the local forages and by-products. To maintain the intake it is necessary to optimize the symbiosis between the animal organism and the microbial population in the rumen.Firs t of all ingestion must be favoured by using feeds with a high water content and a low cell-wall content. It is then necessary to stimulate microbial activity in the rumen and the increase,i n heat production must be avoided. To favour the use of local ressources it is necessary to adapt technological methods to preserve' an d improve the forage value and toutiliz e by-products.

Introduction In order to be productive an animal must first have a satisfactory level of ingestion ; whereas a minimum is necessary to keep the animal alive and in good health, it is also indisputable that its level of production is closely dependent on the quantities and qualities of the feeds he caningest .

We moreover know that heat can diminish sometimes in quite an important way the animal's ingestion capacity. This is all the more prejudicial to the animal's production level as, at the same time, the nutritional value of feeds and more particularly forages is lower in warm and arid regions.

In this paper, I will try to reason the Feeding Strategy for animal production in warm and arid regions by dealing successively with : - the digestive and metabolic phenomena considered, - the consequences for the reasoning of adiet , - the means to enhance the values of the local forages and by-products.

I -The digestive and metabolic phenomena In the case of ruminants the ingestion capacity is directly linked to the room which is available in the first stomach compartment (rumen) and this is dependent on the volume of the ingestion on the onehan d and,o n the other hand, on digestion in the rumen.

The latter results from microbial activity and more particularly from the efficiency of the cellulolytic bacteria. It seems that at the digestive level it is necessary to maintain the activity of the microbial population at a maximum level and, as a consequence, to optimize the symbiosis between the animal organism and

64 the microbial population inth erumen .

A drop inth equantit y which isingeste d associated toa lack of water certainly result ina slowin g down of digestive transit which increases thestay'perio d inth erumen . Yet,eve n in this case, feeds must find there anactiv e microbial population.

We must note the fact that ruminants which show the particularity of selecting the most nutritive part of feeds for them (concentrate selectors) thus have a means to give to the microbial populations in their rumens the growth factors necessary to their developements. A study conducted in our laboratory showed that sheep and goats which only received NaOH treated straw had very different behaviours. Whereas the sheep's refusals were made of long straw blades, the goats left a fine powder which means that after a month the microbial population in the goats'rumens had not changed much whereas themicrobia l population of the sheep had diminished so much that itwa sdifficul t forth eanimal s tosurviv e (Table1) . TABLE1 Effect ofNaO H treatment andnitroge n supplementationo f straw onrume n microbial population inshee p andgoat s (number/ml) (Tisserand, Bellet, Masson,1986) - Diet Straw + soja cake NaOHtreate d straw NaOHtreate d straw + soja cake

Species Sheep Goats Sheep Goats Sheep Goats

Totalanaerob y populationx 10 8 6.0±3.0 13.4±5,6 0.5±3.1 9.4±5.9 3.5±1.9 9,9+9,8 Cellulolytic x10 7 36.8+16.4 74.5+14.8 2.8+1.7 46.5+17.5 29.4±9.7 53.6+17.6 Amylolytic x10 6 57.5±23.5 99.7±33.4 4.0±2.2 62.2+15.2 21.6+8.1 65.5+17.6 Proteolytic x10 7 25.7+11.7 61,5+30,2 4.2±2.5 19.4±24.8 22.9+13.057.1±25. 5 Protozoa x10 5 2.4+1.3 2.2+0.8 1.2+1.3 3.8+1.5 2.6+0.7 10.2Ü.4

Moreover, the fineness of the crushing of ingested feeds observed from samples taken in oesophageal cannulas seems more important ingoat s than sheep (Table2) . TABLE2 Comparative granulometry ofoesophaga l bowl preleved onshee p and goats (Masson etal , 1989) Particle % <0, 8m m <0, 4m m

Sheep Goats Sheep Goats Alfalfa hay 25.1 26.2 9.2 9.7 Straw + soja cake 32.6 33.1 17.9 21.3 NaOH treated straw 38.2 49.4 - —

Lastly, the retention time of feeds in the large intestine which is longer in thecas e of goats could explain a better useo f feeds (Table 3),th e shorter stay period in thegoats' s rumens could then bea consequenc e ofth efac t that theparticle s aremuc h finer in

65 this case. TABLE 3 Retention time in sheep and goats (Alrahmoun, 1985) Diet Ray-grass hay NaOH treated straw

Species Goats Sheep Goats Sheep

Average total retention time (hr) 42 41 73 67 Reticulo-rumen retention time (hr) 27 30 58 62 Difference 15 11 15 5

From a metabolic point of view this more efficient symbiosis in some ruminants could be linked to two other factors. - the capacity of saliva, in particular, to recycle blood urea which is certainly also recycled directly through the rumen's wall (Table4) . TABLE 4 Nitrogen utilization by sheep and goats with different diets (Masson, Alrahmoun, Tisserand, 1986) Diet Ray-grassha y NaOHtreate dstra w NaOHtreate dstra w+ lactose

Species Goats Sheep Goats Sheep Goats Sheep

CPintak e g/kgLW0-75 4.6±0.4 5.11+0.03 0.77±0.05 l.OiO.1 0.73±0.82 0.96±O.19

Ureaplasmati c mg/100ml 17.7±2.2 18.6±3.6 10.3+1.0 9.1+1.0 5.6+1.6 8.5+0.8

Urineure a g/day 4.0+0.4 5.7±2.2 2.2±0.4 2.8±0.5 0.7±0.2 2.5±0.4

As a matter of fact in a diet which is very deficient in nitrogen, which is often the case of forages in warm and arid areas, the presence of lactose in the digestive tract results in the recycling of the blood urea by goats as is shown by the values of the rates of blood and urinary ureas, whereas this is not true for sheep : - a particular type of hydric metabolism, a well known phenomenon in dromedaries but which also appears in goats as opposed to sheep.

Yet the main problem remains the possibility for the animal to eliminate the body heat produced in excess to prevent the rise of body temperature.

It seems that this phenomenon is all the more important as the animal whose production level is high produces an increase of heat increment.

As a consequence, animals of a little size and whose ratio between skin surface and body volume is large have more possibilities to eliminate heat per unit of body surface. This gives an advantage to

66 individuals of arang y type and having well developped extremities.

Yet, one must note the fact that ruminants are less capable than other herbivores such ashorse s of eliminating heat in excess by perspiration.

As a consequence, in order to exploit the forage ressources inwar m and arid regions,i t seems better to use adapted species, such as dromedaries, and zebus than bovine races from temperate regions, and small ruminants,goat s in particular, are interesting too.

How toreaso n adie t First of all,ingestio n must be favoured, by using feeds which can be chewed and swallowed without great amounts of saliva : - containing as much water as possible which moreover helps cover the animal's needs inwater , - by using as much as possible young forages whose contents in cell-wall glucids are not too high and which do not require too long achewin g time, - by distributing crushed or flattened rather than more or less finely ground cereals which necessitate a larger quantity of drinking water, - by giving complements under the form of liquid feeds and by-products such asmolasse s for example.

It is then necessary to stimulate microbial activity in the rumen and more particularly to favour the maintaining of a population of active cellulolytic bacteria. - by trying to limit acidity in the rumen with feeds whose regulating power is high : leguminous plants and in particular alfalfa,whic h because of its high content in calcium, is better than graminae (Table5) . TABLE 5 Effect of feeding different supplements on intake of poor quality roughages, liveweight gain and calf birthweight inpregnan t cows (LINDSAY,MASO N and TOLUMAN, 1982) Liveweight Dry matter intake g/d Calf gain birthweight Treatment g/d Roughage Total kg

C -815 4.21 4.24 22.0 US -308 6.21 6.33 30.9 PP 750 8.12 9.13 32.1 L 405 6.68 8.47 32.1 SEo f Means 105 0.17 0.17 0.7

PP =U S +protecte d protein;L =U S + 2k g of lucerne meal/d

- by bringing whenever it is possible energy under the form of simple glucids (sugar) which favour the development of protozoa instead of starch. In the case of poor forages it is better to complement with sources of energy from digestible cell-walls as shown in Fahmy,Le e and Orskov's whork (1984) (Table 6)

67 TABLE 6 The digestibility of dry and organic matter from ammonia- treated straw and mixtures with rolled barley and sugar beet pulp. The predicted digestibility is also given, together with the calculated digestibility of the straw in the mixtures. (Fahmy, Lee and Orskov, 1984) Diet Digestibility Calculated (g/d) of dry matter digestibility (g/kg) of straw (g/kg)

Ammonia-treated straw (ATS) 533 533 Sugar beet pulp (700) ATS (3000) 705 403 Rolled barley (700) ATS (3000) 654 218

- by distributing, in this case too, forages rich in diges­ tible cellulose and relatively poor in lignin.

An increase in heat increment must be avoidied by'respectin g the fundamental balance of the diet and in particular the energy- nitrogen equilibrium. Any nitrogen excess, in particular under the form of proteins, results in the production of heat increment linked to the elimination by the organism of nitrogenous matters in excess.

One must thinks of an adapted mineral complement, concerning in particular trace elements which can present important imbalances.

This is the case too of the vitamin complement. A supply of vitamin A is often necessary because a low consumption of forages disminishes the supply in carotene whose transformation into vitamin A is limited by the high lignin content of the forages.

The same is certainly true of some vitamins in the B group. Although these are produced by the microbes in the rumen and absorbed in the intestine they are not always numerous enough in the ruminai content to optimize microbial growth.

It is moreover highly recommended to try and distribute the feeds in the shadow in order to prevent excessive dehydratation due to the sun and to favour the consumption of feeds at night. The distribution of cool water (at a temperature of 20 to 22°C) is also a very favourable factor to obtain a larger ingestion of dry matter.

To favour the use of local ressources - by_ enhancing the value of by-products. There are many by­ products or co-products of the local agro-alimentary transformation industry. Iwil l only mention a few as examples : * citrus pulps and other waste of fruit production and transformation which generally constitute, like beet pulps, energy sources which can complement poor forages without reducing their energetic value too much, * fish solubles or poultry litter, which constitute sources of soluble nitrogen, and contribute to the ammoniac supply, allowing a good microbial growth. The residue of oil extraction from oleaginous seeds, full

68 of protein nitrogen, can bring because it is digested in the intestine a fairly large quantity of the amino acids which the animal needs as appears in table 7.

- by choosing well-adapted methods to preserve the forages, and by using all haymaking techniques at night to avoid too much dehydratation and damage due to the direct action of the sun. * by using whenever possible ensilage rather than haymaking. * by avoiding the distribution of compressed dehydrated forages which are badly eaten in warm climates and which necessitate large amounts of water because the animal needs to rince its mouth out to get rid of the residue of crushed feeds which makes up a paste with saliva and limits swallowing.

- through the adoption of adequate technologies to improve lignified forages. Several chemical methods can improve the nutritional values of lignified forages and by-products. One must be very careful when using OHNA which is very efficient but which in arid areas presents the major drawback of leaving on the ground large quantities of Na in the animals'faeces. On the other hand, the use of anhydrous NH3 has proved effective, as appears in the works of many authors. We can name Orskov and Dolberg (1985) table 8. TABLE 7 Effect of feeding 150 g fish meal or 300 g oil cake (mainly mustard oil cake) on growth rate in calves. Urea treated rice straw was offered ad libitum (Saadullah, Haque and Dolberg, 1982) Treatment Dry matter intake (kg) Liveweight gain g/d

Control (C) 3.0 143 C + 150 g fish meal 3.2 357 C + 300 g oil cake 3.3 188

TABLE 8 Effect of different rumen environments on the disappearance of dry matter from nylon-bags incubated in the rumen for 48 hours. (Orskov and Dolberg, 1985) Rumenp H Rumen untreated Amnonia- Hay amnonia straw treated Feed (mg/1) straw Untreatedstra w 6.9 268 443 607 605 Ammoniatreate d straw 6.8 244 541 648 652 Hay 6.5 212 495 629 638 S.E.o fmean s 0.1 19 18 19 21

As a matter of fact supplying ammoniac produces a double effect. Because of its chemical action it helps modify the structures of the plant cell walls and thus they are more easily digested at the same time as it brings extra nitrogen.

69 Yet in order for the supply in nitrogen of NH3 to be veil used there must be enough energy ready for use in the rumen to favour a good synthesis of the microbial proteins. This could be obtained with molasses (table9) . TABLE 9 A comparison between treatments with ammoniac in the oven or the millstone and the effects produced by an addition of molasses ( Butruille, 1983) Control straw Straw NH, Straw NH, +] nolasses % % %

Straw ingestibility gDM/kg LW0-75 38.5 100 42.1 109 51.5 134 Straw digestibility % Organic matter 48.6 100 54.8 113 54.6 113 Crude cellulose 57.6 100 65.1 113 68.9 119 Useo f ingested DOM .. g/kg LW0-75 17.8 (100) 22.2 (125) 21.9 (123) N retained g/head/d 1.. 4 (100) 1.7 (120) 3.8 (270)

As it is difficult to find gaseous ammoniac (NH3) in some countries it is possible to use a urea solution instead. When a few recommendations are followed, one gets results which are very near those observed with ammoniac (NH3) table 10. Moreover, when the treatment is done in warm weather it does not seem necessary to add a source of urease, table11 .

One can even sometimes treat poor forages and in particular straws with liquid manure or animal urine.Thes e two extreme solutions are, as a rule, reserved to cases of important dearth in order to save the animals

There are also treatments to extract the plant fibres.Ye t these techniques,whic h were perfected to make paper, seem at this point too expensive to be recommended in cattle breeding. TABLE 10 A comparison between the urea (+soja ) treatment + theNH 3 treatment. (Salehe t al, 1990) Straw intake Inviv o digestibility g/kg LW0.75 (maintenance level) Treatment DM OMD DOM DCF

Control 46.4 = 100 23.6 = 100 42.8 = 100 55.8 = 100

NH3 110 112 126 117

Urea-soja 114 166 133 121

70 TABLE 11 Effect of an addition of a source of urea (soja). (Besle et al, 1990) Straw intake In vivo digestibility g/kg LW0,75 (maintenance level) Treatment DM OMD DOM DCF

Control 34.6 = 100 12.6 = 100 39.2 = 100 48.7 = 100

Urea-soja 138 177 121 131

Urea 150 177 122 130

Conclusion

The feeding of animals in a warm climate asks for awel l adapted strategy and cannot be efficient if limited to a mere transfer of methods which are successful in humid temperate climates.

One must think the problem out :

- at the level of the choice of animals (species and races). For example, goats seem better adapted than cows to produce milk because they can use poor forages better.

- at the level of the alimentary resources :on e must try and enhance the value of local forages and by-products, as much with adapted additions as with efficient and cheap technological treatments.

To sum up we can say that the feeding of the livestock in warm climates must contribute as efficiently as possible to the production of animal products for the men but also at the same time it should result in the relative economic independence of the concerned countries.

References

Alrahmoun W., 1985 -Utilisatio n digestive comparée chez les caprins et les ovins.Thès e Université de Dijon, 213 pages.

Besle J.M., Chenost M., Tisserand J.L., Lemoine J.P., Faurie F., Saleh H., Grenet N., 1990 -Ammoniatio n of straw by urea :exten t of ureolysis and improvement of nutritive value with moderate water addition.

Butruille M., 1983 -Etud e de l'amélioration de la valeur nutritive de la paille par le traitement à l'ammoniac en meule. Mémoire de fin d'études ENITA Quétigny, 59 p.

Fahmy S.T.M., Lee N., Orskov E.R. (1984) -Effec t of different supplements on digestion of ammonia treated straw. Animal Production, 38.

71 Lindsay J.A.,Mason G.W.J., Toleman M.A. (1982) - Supplementation of pregnant cows with protected proteins when fed tropical forage diets. Proceedings of the Australian Journal of Animal Production (1982), 14, 67-68.

Masson C, Alrahmoun W., Tisserand J.L., 1986 - Etude comparée de la quantité ingérée, de la digestibilité, de l'utilisation de l'azote, du temps moyen de rétention et du comportement alimentaire chez les jeunes caprins et ovins recevant différents régimes.Ann . Zootech., 35(1), 49-60.

Masson C, Faurie F., Arista F., Tisserand J.L., 1989 -Compariso n of the chemical composition and the particle size of alimentary bolus in goats and sheep fed with various diets. In :"Journée s herbivores" INRA Paris 16-17 mars 1989.

Orskov E.R., Dolberg F., 1985 - Recent advances in Ruminant nutrition and their relevances tomil k production in developing countries.I n Milk Production in Developing Countries.A.J . SMITH ED.Edinburgh , p. 177-192.

Saleh H., Koenig M., Millot J.C., Tisserand J.L., 1990 -Effect s of the treatment of straw with NaOH and urea solutions on ingestibility and digestibility in sheep.Reprod . Nutr.Dev . suppl.2, 173.

Saadullah M., Haque M., Dolberg F., 1982 - Supplementation of alkali treated rice straw. Tropical Animal Production, 1, 187-190.

Tisserand J.L., Bellet B.,Masso n C, 1986 -Effe t du traitement des fourrages par la soude sur la composition de l'écosystème microbien du rumen des ovins et des caprins.Reprod . Nutr.Develop . 26(IB), 313- 314.

72 RUMINANTPRODUCTIO N STRATEGIES INWAR MCLIMATES ,A CASE STUDY:TH EIBERI CPENINSULA . ApolinârioVa z Portugal EstaçàoZootécnic aNacional-Val ed eSantarèm-200 0 Santarèm,Portuga l

Summary Heatproduce d byth eanima l isa losstha t penalizes theconversio n efficiency of feed intoanima lproduct . Digestivean dmetaboli chea tproductio n isa cos t factor inanima lproduction . Itsreleas e isa biological mechanismwhic h isfundamenta l inorde rfo rth eanima lt o maintainth ehomoeostati cregulatio no ftemperature .Th e levelo freleas e and itsrat econdition sth e levelo f feed intake.Th emechanis m usedb yth eanima lt oreleas e heatproduce d areaffecte d byth e environmental conditions,an dtherefor eproductivit y isaffected . The geneticvariabilit y isconsidere d inbehaviour , inth e metabolic adaptation, inth ereflexe s infee d intake,i n therat eo fpassag e atreticulo-rume nlevel ,i nth e microbial activity and inth esolid-liqui d dilution.A t metabolic level,hea tproductio n isaffecte d by the equilibrium ofth eabsorbe d nutrientsan db y the physiological natureo fth eanima lrequirements .Th e lack ofth eglucogeni c potentialan dth e increaseo f lipogenic/glucogenic ratioo f SVFAwil l contribute toth e increase ofH P forth e sameamoun to fM E intake.I n relationt oenvironmenta l stress,th emanipulatio n of thesemechanis m leadst oth ecapacit y ofmetaboli c adaptationo f animalst ob e selected.Ther ear emor e possibilities toselec tbase d onth eanimal scapacit y to releaseheat ,tha nt odecreas eheat production .Anima l production subjected toenvironmenta l stressshoul d not bedetermine d byth econcep to fbiologica l productivity butt oadequat eproductivity ,vis-à-vi sth emaximizatio n of localavailabl eresources .

1 Introduction Thedigestiv ean dmetaboli cprocesse stha tmeet th e animal'smaintenanc e requirements and production functionsar eresponsibl e forth ereleasin g of energy in thefor mo fhea t (HP).Thi sfor mo fhea tproductio n isa lossan dmark sth eefficienc y ofth eproductio nsystems . In livebeings, accordin gt oLavoisie r (1789), life isa chemicalproces sdurin gwhic hhea tproductio n isa parameter ofproductio n rates.Animal sdon' t livet o produceheat ,bu tthe yproduc ehea twhil ethe y livean d becausethe y live.Th erat eo fhea tproduction s islinke d toth eanimal' s size,species ,breed ,physiologica l stage (growth,pregnancy , lactation,etc.) , feed andwate r intake,leve lo fproductio n and levelo fphysica l activity.Th eenvironmenta l conditionsth eanimal' shea t 73 production,havin g adirec teffec to nfee d intakean d on digestivemechanis m anda n indirecteffec to nchange s concerning therespirator y enzymesactivitie san dth e protein synthesis.Accordin gt oth eenvironmen t andth e levelo fadaptability ,th eanima l shows,fo ra n equivalent levelo fhea tproduction ,a variabl e capacity forheat storage.Th eadaptativ eabilit yt omaintai n a thermalbalance ,i na "comfort zone"o rthermoneutra l zone,allow sth eanima lt oreleas eo rstor eth ehea t produced. Equation 1show sth ementione d factors.I ti s accepted thatth ethermoneutra l zone isth erang eo f ambienttemperatur ewithi nwhic hth emetaboli c rate isat a minimum andat whic htemperatur eregulatio n isachieve d byno nevaporativ ephysica lprocesse salon e (Bligh& Johnson, 1973).

Equation 1. HP= H L ±H S where HP -Hea tProductio n HL- Hea tLos s (heatreleased ) HS- Hea t Storage

Tscherniak (1866),a squote d byMoor e (1918), stresses therol eo fth enervou s system andth eregulatio n ofth e metabolic ratewhic h isa nessentia l factor forth e productive animal capacity. Breedshea ttoleranc ema ymean ,i nrelativ eterms , poorproducer s if sucha cas e isdetermine d by lowheat production. Itca nb esai dtha t increased production isaccompanie d bymetaboli c incrementwhic h leadst ohea tproduction . Heatproduction ,therefore , isa cos tfacto r inanima l productivity. Inth eoptimizatio n ofanima lproduction ,whateve r the environmental conditionsma ybe ,w e should consider the following aspects (VazPortugal ,1990 ): - natural selection ofth eanima lspecie s (smallan d largeruminants ,herbivore s andwil dherbivore s areth e mostadequat e animalst oavailabl e locallyproduce d resources) - selection of abree dmetabolicall ywel l adapted to certaincondition s (adaptationo fth emetabolis m to undernutrition,climate ,seaso nan dth ereleasin g ofth e HP) - definition ofth etyp eo fproduction ^ inextensiv e conditionsan d inver yho ttemperatures ,meat production isbiologicall y easier andmor epossibl etha nmil k production) - fulfilmento fth eanima lrequirement s (physiological stageo fth e animal)i nth eavailabl e localresource s and inth eseasonalit y ofthes efeed s - characterization,marketin g andth edefens e ofth e gualitv ofth eanima lproduc t obtained (typification of what isproduced) . So,w emust look forruminan tbreed swit hmaximu m 74 fibrous feed intakean dth ecapacit y ofquickl y releasing theH P (VazPortugal , 1988). 2 Theenvironmenta l conditionsaffec tth eformatio no f theanima l product Thedepositio n ofth eanima lproduc tcomponents ,meat andmilk , isa consequenc eo fa se to factivitie so f severalbiochemica l ormetaboli cpathway swhic h are regulated byneuroendocri nfactor san ddepen d onwhat an d howmuc hth eanima leats .Th e "dance"o fth emetaboli c fluxesha sa lott od owit hth ecapacit y of adaptability ofth eanima lt oclimati can d environmentalvariations ; theendocri nan dneura lcontro lmechanism s involved are complex (Blaxter, 1989). Equation 2shows ,i na ver y simpleway ,th eprincipa l pathwayso fpartitio n ofenerg y intakeb yth eanimal ,at organic level,takin g intoaccoun tth eenerg yuse d for maintenance asnonrecoverabl e and leadingt oa nenerg y loss.

Equation2 . EI= E R+ H P where EI- Energ y Intake ER- Energ yRetaine d HP -Hea t Production Interm so fanima lproduction ,energeti c lossesar e correlated toth etyp eo f feed,th e levelo f intakean d thestag eo fth eanimal' sproductiv e life.A s fara s growth isconcerned ,w e should considerth e following aspects (Webster, 1979): - duringgrowth ,th emetabolizabl e energy (ME)exceed sH P and asth eanima lreache smaturity ,bot hvalue s converge - thegreate r efficiency ofth eE R isobserve d whenth e animalreache sabou t 25%o f itsmatur eweight ,decreasin g astonishingly afterwards - thefat/protei nrati o increases inth edail ygrowth ,a s theanima lapproache s itsmatur eweight . All ofth edigestiv ean dmetaboli c factors linked to heatproductio n and itsreleas eaffec tth e energy partition. Itca nb esee ntha tbetwee ndifferen t species andbetwee ndifferen tbreed san d strains,severa l reactionst oclimati c stresstak eplac e (cold stressan d heat stress). Thethermoregulator y behaviour isa n importantcomponen to fth eacclimatizatio n (Mount, 1979). Acclimatizationma y bedefine d asa physiologica l compensatory alterationt oa singl eenvironmenta l factor (Curtis, 1983). Thecompensator y changesar ea consequence ofth emetaboli c adaptability. Themechanism s responsible forth emetaboli c adaptation toth e interactionsbetwee nth evariou s environmental components (temperature,radiation ,humidity ,rainfall ,ai rspeed , wind and draught)ar ecomplex .Th edominan thormone s in themetaboli c adaptationmechanism swhic h are associated toambien ttemperatur evariations ,fee d intakean dth e lipogenic/glucogenic ratioo f SVFAar einsuline , somatomedines,thyroxin e anddefinitel y glucagon inth e 75 caseo fruminants .Th ecalorigeni c effecto f thyroxine (T)an dtriiodothyronin e (T)o fth egrowt hhormon e (GH) and ofth eglucocorticoid s isstressed .Onl y someo fth e aspectso fthes emechanism swil lb epresented . 2.1 Genetic Nature Different animal specieshav evariabl ehea ttolerance . Geneticvariation si nenerg y lossesan dmaintenanc e efficiency (Taylor& Young ,1968 )hav ebee n found between breedsan d strains.A nexampl eo fthis :maintenanc e energyrequirement s are lower inBo s indicustha n inBo s taurusbreed s (Frisch &Vercoe , 1984). Among allsmal l and largeruminants ,th egoa t seemst omor e efficiently supporthig hambien ttemperatures .Th e biological mechanisms responsible foracclimatizatio n arewate r metabolism,respirator y andmetaboli c ratean dhea t release.A nexampl eo fthis :th edail yproductio no f saliva, inth e sameenvironment ,fo rgoat san d sheepwit h thesam etyp eo fdie t is84 8m l ingoat san d 502m l-i n sheep (Sethe t al., 1976). Thissituatio nma y explain the changesbetwee nth etw o species forwate rturnover ,ure a recycling,rat eo fpassag e fromth éreticulo-rume n and retentiontim eo f feedparticle s inth e reticulo-rumen space.Differen tanima lbehaviou r to increases of ambient temperature are linkedt oth ecapacit y ofmor e easily releasing thehea tproduce d and ofreducin g maintenance coststhroug hmetaboli c rate.Th e neuro-endocrin structure,siz ean d colouro fth eanima l justify the geneticdifference s betweenbreed san dstrains .

2.2 Feed Intake Althoughth econtro lo f feed intake ismulti-factoria l (Baile& Forbes, 1974), ageneralize d opinion inrelatio n toth e intervention ofthermo-regulatio n inth e homeostaticregulatio n of feed intake (Verstegen,1973 ; Close, 1978;Christiso n &Williams ,1982 )seem st oexist . Heatstres scause sa reductio n ofth efee d intake level inth eanimal ,tha tcanno tb eonl yexplaine d bya reduction ofth erat eo fpassag e fromth ereticulo-rumen . Thethermo-regulator y control andth ebasa lmetabolis m may justify thereductio n of feed intake.I nth epresenc e ofhea t stress,lowe rtha nnorma lquantitativ e levelso f somatotrophinsan dtyroid ehormone s areverifie d (Bianca, 1965; Beede &Collier , 1986). Theproductio nan d dissipation ofhea tproduction ,a sa consequenc e ofth e reticulo-rumen fermentation,question sth e imbalance betweennutrient s effectingmicrobia lactivity . Inhot environments there isa tendenc y forth ereductio no f feed intakedu et oth eadditiona lproductio n ofheat , which iscause d bydietar y limitationstha taffec tth e ruminai functiono rth eus eo fnutrient sb yth ebod y organs (Nolan &Leng , 1989). Non specific interactions between feedsan dmetabolite sma yreduc eth ehea to f reticulo-rumen fermentation,cause db ya n extracellular processo rb yth emaintenanc e of an intracellular ionic 76 concentration, byenzym eturnover , bymicroorganism s and uncoupling biochemical reactions.Productivit y will be affected bya decreas e of feed intakea sa primar y factor.The proble m will beho wt okno wwhic h nutrient limitsth e efficientutilizatio n ofth eother s (table1) . Table 1.Effec t of supplementso ndr ymatte r intakean d liveweigh t changeo fcattl egive nnativ epastur e hay. Data fromLindsa y &Loxton ,1981 . DM intake Liveweigh t change (kg/day) (kg/day) Basaldie t (hay) 2.26 - 0.41 Hay+ urea/ S 3.01 - 0.32 Hay ±protecte d protein (PP)3.72 0.11 Hay ±urea/ s +P P 4.43 0.21 SE oftreatmen tmean s 0.18 0.061 SE- standar d error 2.3 Digestiveutilizatio n atreticulo-rume n level ' Heatstres sha sth etendenc y of increasingth e reticulo-ruminal digestibility duet oth e facttha ti t increasesth eretentio n timeo f feedparticle s inth e reticulo-rumen,allowin g a longercolonizatio n offee d particle byreticulo-rume nmicroorganisms .Fo rpoo r forages,suc ha situatio ncause db y lower levelso f intakema y improvedigestibilit y butno tproductivity . However,slightl y greaterdigestio ncoefficient s during heatstres sar epossibl e ifth emicrobia l activity is stimulated. Table 2 (Schneider et al., 1988)show sth e effecto fhea tstres so nth ereticulo-rume n activity using cowskep t inenvironmenta lchambers . Table2 .Environmenta l effectso nrat eo fpassag eo f liquid and soliddigest athroug hth erume n inth e chamber experiment (Schneider etal. , 1988) Thermo-neutral Heatstres s (LeastSquar eMeans )

Liquid diluitionrat e (%/h) 10.9 8.6 Solidturnove r rate (%/h) 3.6 2.8 Meanretentio n time (h) 27.9 38.4

A lowerrat eo fpassag ema yb ecompensate d ifa n intentional dilution rateo fth ereticulo-rume n content isallowed ;thi s isfavoure d byhighe r intakeso fwate r or feed.A lowerchang eo fth e siteo fdigestio nma y allowa n increase infee d intake.Harriso n &McAlla n (1976)verifie d thatth eutilizatio n of inorganic salts leadst oa n increaseo fth edilutio nrat eallowin g an increase inth eefficienc y ofth e reticulo-rumen digestion twot othre etime sdu et oth e increase ofth e 77 turnover rateo f individualmicroorganism s andt oth e reductiono fth eretentio ntim eo fbacteri a inth e reticulo-rumen.A sa consequence ,a n increaseo fY .AT P versusM .AT P isobserved .Col d favoursa n increaseo f dilution of about 15% (Kennedy etal. , 1986)an da n increaseo fth ewate rturnove rrat ema yreduc eth e retentiontim eo f feedparticles .Th eanima lwil lb e betterof fonl y ifth e increaseo fth e reticulo-rumen digestibility iscause db ya n increaseo fth emicrobia l activity inth ereticulo-rumen .I nthi sway ,th epossibl e maximization ofth emicrobia lprotei nsynthesi s and its passaget oth eabomasu m isassured .Th e increase ofth e levelo f intake forth esam efee denable sa n increaseo f thepassag eo f feedst oth eintestina ldigestio nwhic h leadst osom eadvantage s forth eanimal .Dello wet al. (1989)obtaine dvalue s from 30t o40 %o fN intake escaping fromreticulo-rume n hydrolysiswhen ,i nsheep , 400gr/da yo f freshimatur erye-gras so rclove r intakes weresubstitute d by 1400gr/da yintakes . It isknow ntha tth eturnove rrate so f liquidand - soliddigest a andtota lvolatil e fattyacid swer e lower inth ehea tstres stha n inwhat happene d inth e thermoneutralzone . 2.4Metaboli cutilizatio no fth eabsorbe d nutrients Temperaturevariations ,namel yhea tstress, affec tth e homeoreticmechanism stha tsea kt oestablis h the maintenance ofphysiologica l equilibrium (homeostasis). Theprotei ndepositio n isobtaine d atth ecos to fa hig h energy intake (Geay,1984 ;Tabl e 3)an dwit hhig hHP . It isknow ntha tth eprotei ndepositio n rate increases atlowe rtemperatures .A thig htemperatures ,ther e isa limito fprotei ndeposition ,cause db yth e feed intake depression.Th e lacko fglucogeni cpotentia lan d the increaseo fth e lipogenic /gluconeogeni c ratioo fSVF A may, inth epresenc eo fhighe rvalue so facetate ,reduc e theefficienc y of energy intakeand ,i nth epresenc eo f difficulties ineliminatin gproduce dheat ,reduc eth e quantity of feedintake . Qualitativemodification so fth e reticulo-rumen fermentationma ymean ,i nhea tstres sconditions ,a greaterdecreas e ofproductio n andefficienc y ofenerg y utilization atmetaboli c level.Th eglucogeni c potential limitsth e levelo fproductivit y tob eobtaine dan d is moreexpose d tohea tstres stha nt ocol d stress.I nthi s way,a selectio n of feedsan dmixtures'whic har e less calorigenicma y favour,i nho tenvironments ,th e animal's productivity asth e increase ofth e gluconeogenic capacity,a tmetaboli c level,ma yreduc eth eH Peffects .

78 Table 3.Estimatio n ofth eutilizatio n ofmetabolizabl e energy for fatdepositio n (Kgf)an dprotei n deposition (Kgb). Data fromGeay ,1984 . Source Kgf Kgp

Geay .75 .20 Orskovan dM cDonal d (1970) .80 .34 Rattreyan dJoyc e (1976) .56 .22 .95 .18 1.28 .18 Bickellan dDürre r (1974) 1.02 .34

3 Final remarks Depending onth eanimal' sdifficultie s inreleasin g HP, iti srecommende d thatth efollowin g principles shouldb esought : - thechoic eo fanimal swhic h aremor eadapte d toth e environment andwhos e size isadequat et oth e available localresource s (duet oth e increaseo fth ereticulo - rumenvolume ,increas eo fth ereticulo-rume ndilution , reduction ofmaintenanc e costs,withou t affecting the metabolic ratean dreductio n ofcost swit hth ephysica l activity ofth eanimal ) - seaking ofanimal swit hgoo d capacity forreleasin g the metabolic heat - utilization of lesscalorigeni c foragesan d feedswhic h increaseth eglucogeni cpotentia l atmetaboli c level.W e mustai ma ta mor econvenien t fibrousfeeds/cerea l ratio (thelipogenic/gluconeogeni c ratioo fth e feed) - theoffe r ofby-pas sprotei nsource stha tcontribut e to a protein synthesis andglucogeni c potentialat metaboli c level - tomak eth ephase s ofgreate rproductiv e requirements (1stthir d ofgrowt han dtw omonth safte rth ebeginnin g of lactation)coincid ewit hperiod so fth eyea rdurin g whichth eenvironmenta l temperatures fall inth eanimal' s "comfortzone " - methodso fmanagemen ttha tavoi dth eanimal' s feeding duringperiod so fgreate rhea t - stimulation ofth ewate r intake inorde rt o leadt oa n increase ofth eanimal' swate rturnover . Thephylosoph y defended forth eMediterranea n areas is the fitting ofth eanimal' s characteristics inth e environment,b ymaximizin g theanimal' spotentia l adapted to localresources .Th e localbreed stha tpresen t competitivemaintenanc e andbreedin gcosts ,ma y beth e basiso fbee fproductio n incountrie swher egrazin g conditions arestrictl y limited (milkproductio n is reduced)bu twher egrazin g indr ypasture swit h supplementation ispossible .I nhars hdr y seasons,th e bestadapte d ruminantt o localproductio n conditionsmust be found, inorde rt oobtai nth eadequat eproductivit y in spiteo fth e fluctuating nutrientsupply .

79 References Baile, C.A. &Forbes ,J.M. , 1974.Physiol .Revs .54 :160 . Beede,O.K . &Collier ,R.J. , 1986.J .Anim .Sei . 62:543 . Bianca,W. , 1965.J.Dair yRes .32 :291 . Blaxter,K. , 1989.In :Energ yMetabolis m of FarmAnimals . EAAP pub.n°43 . Bligh,J . &Johnson ,K.G. , 1973.J .Appl .Physiol . 35:941. Christison, G.I.& Williams ,CM. , 1982.CR CHandboo k of Agricultural Productivity, Vol.II ,p g69 . Close,V.H. ,1978 .Brit .J . Nutr.40 :413 . Curtis, S.E., 1983.In :Environmenta l Management in AnimalAgriculture , edit: Iowa StateUniversit yPress . Dellow, D.W., Mosely, G. &Nolan ,J.V. , cit.b yNolan , J.V. &Len gR.A. , 1989.In :Feedin g Strategies for Improving Productivity ofRuminan t Livestock in Developping Countries, edit:IAEA ,Vienna . Frisch,J.E . &Vercoe ,J.E. , 1984.J .Agri .Sei .103:137 . Geay, Y., 1984.J .Anim .Sei .58 :766 . Harrison, D.G. &McAllen ,A.B. ,1976 .In :Digestiv e Physiology andMetabolis m inth eRuminant , edit.Y . Ruckbush &P .Thivend ,MT PPress ,Lencaster . Lindsay,J.A .& Loxton , I.D., 1981.In :Recen t Advances inAnima lNutritio n inAustralia , edit.D.J .Farrel , University ofNe w England. Publ.Unit ,Armidale . Kennedy, P.M., Christopherson, R.J. andMilligan , L.P., 1986. In:Contro l ofDigestio n andMetabolis m in Ruminants, edit.L.P .Milligan , PrenticeHall , Englewood Cliffs,N.J .Moore ,L.M. , 1918.Am . J. Physiol.46 :253 . Mount, L.E., 1979.In :Adaptatio n toTherma l Environment: Man and hisProductiv eAnimals ,edit .Edwar d Arnold, London. Nolan, J.V. &Leng ,R.A. , 1989.In :Feedin g Strategies for Improving Productivity ofRuminan t Livestock in Developing Countries, edit IAEA, Vienna. Schneider, P.L., Beede,D.K . &Wilcox , C.J., 1988.J . Anim.Sei .66:112 . Seth, D.,Day , G.S.,Yaday , P.C. and Paudry,M.D. ,1976 . Indian.J .Anim . Sei.46 :660 . Taylor, St.C.S .an d Young, G.B., 1968.Anim . Prod. 10:393. Vaz Portugal,A. , 1988 In:Ruminan t Production inth eDr y Subtropics.Constraint s andPotentials .EAA P pub. n°38, PudocWageningen , Holland. Vaz Portugal,A. , 1990.In :41s tAnnua lMeetin g of EAAP, Toulouse,France . Verstegen, M.W.A., 1973.Brit .J . Nutr. 30:21 . Webster,A.J.F. , 1979.30t hAnnua lMeetin g EAAP. Harrogate, England.

80 ALTERNATIVE BREEDING PROGRAMS FOR DAIRY CATTLE IN NORTH AFRICA

Abdesselam EDDEBBARH Institut Agronomique et Vétérinaire Hassan II B.P. 6202 Rabat-Instituts, RABAT - MOROCCO.

ABSTRACT

During Last decades breeding methods for dairy cattle evolved rapidely. A major element in this evolution is the use of proven sires through artificial insemination. Recently embryo mani­ pulation became a factor. It is well established that breeding strategies for dairy cattle should be based on the characteristics of the production systems in place in addition to national objectives. This paper discusses some alternative breeding programs for dairy cattle in North Africa based on 1) the demand for milk and dairy products, 2) cattle ressources and 3) some environmental and management characteristics. The cattle population is still dominated by native breed mainly Brune de l'Atlass which is adapted to some environmental constraints of the area but with low productivity. The introduction of improving genes mainly through importation of heifers from dairy breeds started as early as the colonisation of these countries. While some records above 8000 Kg/cow/ yr. are registred national averages for these animals are arround 3000Kg/cow/yr. Environmental and management constraints limit produc­ tivity. The use of semen from proven bulls is the alternative to improve genetic potential of these animals. This constitutesa challeng e for national livestock services. Cooperation between the countries of the area is of benefit to such programs. For the native animals the paper discusses opportunities to improve productivity through selection and crossbreeding.

Descriptors : Dairy cattle, breeding, crossbreeding, north africa.

I. INTRODUCTION : Breeding methods for dairy cattle have evolved rapidely during last decades. A major element in this evolution was artificial insemination through the use of semen from bulls with high breeding values. Druring last years technics based on embryo manipulation have been developed and used beyond experimental stages in some cases.

81 It is well established that breeding strategies for dairy cattLe-should be based on animal and environmental ressources :(feed, management ...), which vary from one area to another and even from one production system to another within the same country. In Europe and North America, intensive dairy cattle produc­ tion with highly selected breeds has been a major component of animal agriculture for many decades. In North Africa, the dairy sector was mainly based, for a long time, on extensive systems with native breeds. Recently, improving genes have been introduced through direct importation of heifers and semen. The industry is developing, but several questions are still open. A major one being the development of appropriate genotypes and breeding programs for the various production systems in the region. This papers discusses alternative breeding programs for dairy cattle in the area based on : 1) Demand for milk and dairy products 2) Cattle ressources 3) Some important environmental and a management caracteristics: feeding the dairy cows, and reproductive management.

II. DEMAND FOR MILK AND DAIRY PRODUCTS IN NORTH AFRICA : The situation of the actual and projected demand for milk and dairy products in North Africa can be summarized as follows : (Bourbouze et al 1988 and Auriol 1988). - Current consumption levels are on the average lower than world average and nutritional standards :e, g about 50 Kg of equivalent milk/capita/year in Morocco. - The amount of fresh milk available per capita has been stable eventhough total production has increased. - The demand for milk and dairy products has increased more than 50% due to an increase in human population and to increasing pursha- sing power of consumers especially in cities. - Importation of dairy products has increased rapidelywhic h has increased the dependancy of the North African countries on exporters of these products. - Reported projections made by FAO and other organizations indicate that demand for dairy products will continue to expand and probably accelerate in the region.

III. CATTLE RESSOURCES IN THE REGION : 1. Genetic structure of the cattle population : 1.1. In North Africa the cattle population is dominated by animals from native breeds mainly Brune de l'Atlas. In 1986, percen­ tages of animals from these breeds were 88.4,84. 8 and 76.0 for Morocco, Algeria, and Tunisia respectively (Guessous and Eddebbarh, 1988). The number of these cows exceeds 1.900.000 (Nardone and Villa 1990).

82 1.2. Improving genes have been introduced inth eare a through direct importation ofheifer s andsemen . Importation ofheifer s started asearl y ascolonisatio nbu t changes became significant recently. Their percentage increased conti­ nuously :Fro m9.9 %i n197 5t o18.6 %i n1988 ,an dfro m 5.1%i n197 0 to 24% in198 6i nMorocc o andTunisi a respectively. Over 30% of imports have been friesian from Europe. Holstein genes have also been intro­ duced from North America andEurope .Thei r percentage isexpecte dt o increase asi ti scountrinuousl y increasing within countries exporting genes toNort h Africa.

2. Structure ofdair y industry: While theimportatio n ofheifer s created ane wcattl e popu­ lation,th edair y industry inth eregio n isstil l dominated bysmal l herdso fnativ e breedsan d crosses between native andimprove d breeds: - InAlgeria ,42 %o fnationa l milk production comes from 70000 0 cowso fnativ e breeds andthei r crosses located onsmal l herds; 38% oftota l milk isproduce d byabou t 60.000 improved cows located on farmso f less than 5hectare s ;th eremainin g 15%o ftota l milk is produced byabou t 32.000 improved cows located inherd s averaging 50 cows (Yakhlef 1988). - InMorocco ,abou t 75%o fth etota l milk processed bydair y plants is collected through milk collection centers.Ther e were about 103.000 farmers registred within these centers in1986 ,an dthes e farmersha d an average of2.5 7cow s anddelivere d andaverag e of88 4liter spe r cowpe ryea r toth ecollectio n centers (Eddebbarh, 1988).

3. Productivity ofcow s inNort h Africa: 3.1. Cows from native breeds: Average levels ofproductivit y ofcow s from native breedsar e very low: arroun d 450K gpe rlactation .A sshow n bytabl e 1,calvin g intervals arearroun d 18month s andheifer s clav forth efirs t time at ages between 3an d4 years . 3.2. Improved cows : 3.2.1. Achieved production ofimprove d cows matches genetic potential only infe wfarms . These have irrigated land andaccoun t for only asmal l percentage oftota l production.I nthes e situations herd averages forHolstei n cows canexcee d 6000 Kg/cows/year (tables2 and 3).However ,o nth eaverage , levels ofproductio n forFriesia n and Holstein cowsar ebelo w their breed averages inEurop e andNort h America. Reported averages forlarg e populations of Friesian cows were 3000 Kg/cow/year inTunisi a (Bourbouze etal , 1988), 2500 Kgi nth e public sector and330 0K gi nth eprivat e onei nAlgeri a (Yakhlef, 1988). InMorocco ,estimate d average forimprove d population ofcow s (purebreds andcrossbreds )wa s250 0K go fmilk/cow/year . Average per­ formanceso fcow s involved inmil k testing programs arehighe r :516 5K g forth eHolstei n breed and458 7 forth eFriesian . Intraherd

83 Table 1.Productivit y of native breeds innort h africa

Milk/cow/ Lacta­ Reproductive Age at lactation tion efficiency first Breed Country (Kg) length Calving Ferti­ calving (days) interval lity (years) (months) %

Brune de 1 L'Atlas Algeria 900 120-180 18 - 3-4 Brune de _ .. 2 l'Atlas Tunisia 350-450 <180 - 65 - Brune de 3 l'Atlas 543+269 143+74 Morocco Brune de l'Atlas Morocco 178+262 78+65 Hetero­ geneous Morocco 450 18 •• 4 1.Yakhl e f,198 8 3. Eddebbarh,198 6 2. Bourbo uze, 1988 4.e h raibi,198 5

Table 2.Productivit y of Holstein and Friesian cows in North Africa (Kg/ cow/la c tation). 2 Mo rocco-' Tunisia Herd nun ber Holsteiri Friesian Holstein Friesian

1 3330 4098 2232 2175 2 4351 4871 3259 3245 3 5646 5363 3744 3616 4 7415 6483 5374 4581 5 8343 - 6029 5900 1. Eddebbarh and Bennis not published (result relative to 1989-90) 2. Adapted from Djemali et al (1988).

Table 3. Performances of Holstein and Friesian cows involved inmil k testing programs inBensliman e Morocco :calvin g years 1987-88 (Kg/305 days).

Holstein Friesian Average 5165 4587 Min. 2909 2655 Max. 8909 6239

Eddebbarh and Bennis not published.

84 records vary largly arround the means and Large variations are also observed between herd averages ; from Less than 2500 Kg to more than 8000 Kg/cow/year (Tables2 and 3).Majo r reasons for Low productivity depend on environment and management constraints.

IV. ENVIRONMENTAL AND MANAGEMENT CHARACTERISTICS : This chapter summarizes the situation of feeding and repro­ ductive management of dairy cows in North Africa.

1. Feeding : The cLimat in North Africa is a Mediterranean one with Large variations within and between years. The most important charac­ teristic is the existance of a dry season in summer. Guessous and Eddebbarh 1988 reported that the characteristics of the cLimate in North Africa affect feeding calendars, forage productivity and forage nutritive vaLue for dairy cows. The authors concluded thaf'where 4 irrigation is not possible during summer, feeding fresh forage to dairy cows is not possible all the year arround, preserved forage must be utilized during dry season otherwise cows will have to depend on straw as the main source of fiber during summer and fall. Thus, insuring a regular and high quality forage diet to high producing dairy cows seems to be difficult".Par t of the difficulty originates from inadequate technics utilized in planting, managing and preserving forages. One consequence of this situation is that cereal straw tends to be extensively used even by herds with high genetic potential. The other consequence is the extensive use of concentrate. The amount of concentrate used can reach 0.7 Kg per Kg of milk produced (Eddebbarh 1986).

Coupounding the forage problem is a lack of nutritionally balan­ ced concentrates and mineral supplements to provide the animals with a balanced ration. Most producers Lack knowledge of the nutritional value of various feedstuffs and of nutrient requierements for maintenance, growth, reproduction and milk production.

2. Reproductive management : Knowledge of the oestrus cycle and the importance of oestrus detection in reproductive management is Limited. Poor nutrition also restricts reproductive performance. Artificial insemination became a factor in North Africa since the 60's. The activity has grown slowly with much variation from one year to another. The number of cows artificially inseminated is low :e, g Less than 5% of the total females in reproduction in Morocco and Algeria. In Tunisia/Brahmia and Ben Dhia 1989 reported a 22% first inseminations in 1988. The majority of animals artificially inseminated are impro­ ved cows. There are many reasons for the low activity of artificial insemination. A major one is a poor conception of AI by farmers who usually prefer the bull because "they can see what to expect from him". This poor perception is enhanced by poor techniques that result in poor quality semen, improper insemination and low conception rates.

85 Material problems such as inadequate transportation have slowed development. On the other hand, AI has not been used effectively for genetic imrpovement. That is,th e value of the bulls localy produced and used has not been high. There were no progeny testing programs.Bull s were choosen on their pedigree (complete or partial) were and their conformation. In Morocco, Eddebbarh and Moussaif (not published) tried to estimate breeding values of some bulls localy produced in comparison with bulls progeny tested in Europe and who's semen has been improted and used in Morocco. The latter group was highly superior to the former. Average breeding values were +364 and -147 respectively. It is well established that AI contributes to genetic progress only if superior bulls are used. If the bulls used do not have positive breeding values, AI contributes nothing or may be detrimental. The main question that raises from the characteristics of the situation is as follows : Since actual feeding systems and management are real cons­ traints that limit productivity of dairy cows in the area, should fermers continue to use highly producing dairy breeds, or isn't the development of genotypes with lower potential an appropriate breeding alternative for most production systems in the area. Several studies on dairy systems in the area concluded that the introduction of highly selected animals must be achieved along with the intensification of feeding systems mainly through the deve­ lopment of forage production and the use of some byproducts to feed dairy cows (Eddebbarh, 1989). Specialization on milk production (no males raised), eventhough, constitutes an alternative to have optimum production from such animals may not be acceptable to most farmers who produce milk and beef from the same herd.

V. ALTERNATIVES :

Thus the breeding alternatives for the dairy cattle popula­ tion can be summarized as follows. 1. Improved cows population : For the improved cow population (Friesian and Holstein), the main question relative to a breeding strategy is how to improve or at least maintain genetic level. Bulls localy produced for arti­ ficial insemination are not progeny tested.'Importation of semen from progeny testing bulls is an alternative. Some farmers are already doing so. An implemenation of national progeny testing programs will requière astron gorganizatio n of record keeping and milk testing programs. It also requiers a full adhesion of farmers.Achievin g theses programs constitutes a challenges to national livestock administrations. It may offer opportunities to enhance communication with farmers which is necessary to improve the management of dairy cattle in the area.

* These bulls were used before the initiation of a progeny testing program.

86 Such programs will benefit from a cooperation between the coun­ tries of the area where milk testing programs are operating (Morocco, Tunisia' Algeria).

2. Native breeds : 2.1. Selection : While average performances are very low, large variations exist arround breed averages.Eddebbar h 1986 reported a standard deviation of 400K g for a large population of Brune de l'Atlas with a mean of 400 Kg/cow/year. In addition animals from these breeds have great aptitudes for adaptation to some of the constraints in the area. Examples are :

- adaptation to thermal amplitudes and heat stress - disease resistance (Piroplasmose, ) - use of poor quality forages and resistance to undernutrition Selection within these animals,eventhoug h may not produce a rapid genetic progress,offer s opportunitiesfo r farmers in diffucult areas where feed and management are real constraints and where milk is produced as a source of cash with other socioeconomic effects (labor, ...). This, however,requier s an implementation of an appropriate recording and anorganizatio n of the collecting systems.

2.2. Crossbreeding : Crossbreeding was tried in several situations ; inMorocco , the average production for the first lactation of first generation Holstein xNativ e cows was 2545 Kg of milk. Average age at first calving was 2years .Expecte d production of second generation backcross to Holsteini s3733KG .I nTunisi a the average 305 days production of six lactations was 2114K g for the first generation crossbred Friesianx Native and3778K g for the second generation backross (Table 4).I n addition to this, crossbreeding to Holstein sires improved growth rates and feed efficiency of the males.Firs t generation Holstein x Native breed bullocks weighed 460 Kg at 18 months of age (Eddebbarh 1987).

Table 4.Mil k production of crossbred animals Holstein , Friesianx Native in North Africa. (Kg/305 days).

2 . . 1 Morocco Tunisia Expected Realized

F1 2114 (163) 2650 2540 (25)

F2 3778 (148) 3733

( ) :Numbe r of animals 1 :Brahmi a and Ben Dhia 1984 2 :Eddebbar h 1989

87 The Level ofupgradin g will depend onenvironmenta lan d management characteristics.A sshow n byHodge s 1985, performances of crossbred animals decrease ina poo r environment with theincreas e of theproportio n ofHolstein-Friesia n genes.Thi s suggests thati n such environments theoptimu m level ofimprovin g genes shouldb e kept between 50an d75% .Thi s raises thequestio n about thebreedin g method inorde r tomaintai n such levelso fexoti c genes. Various methods have been discussed andtrie d insom e developing countries. These areth ecountinuou s production ofF 1throug h maintainingtw o purebred populations orth eproductio n ofF 1male s tomat e withF 1 females ;o frotationa l crossbreeding.Al lthese ,method s requier a strong organizational structure onth e field andth ecompetenc e of stuff andfarmer s inorde r tocontro l thematin g of individual cows.

REFERENCES:

Auriol P., 1988. Seminaire C.I.H.E.A^M. Le lait dans la rég'ion mediterraneene, Rabat. Bourbouze A., A. Chouchen A. Eddebbarh, J. Pluvinage et H. Yakhlef, 1988. Séminaire CJ.H.E.A.M. Le lait dans la région méditerranéenne, Rabat. Brahmia and Ben Dhia, 1989. Symposium sur l'amélioration génétique des bovins sous climat-Sud Méditerranéen. Tunis.

Chraibi,M .1985 .Mémoir e de3èm e Cycle Agronomie. Inst. Agro. et Vét. Hassan II,Rabat . Djemali M.,Majdou ban dM .Ersini , 1988.Unde r publication. Eddebbarh A.,1986 .Ph .D .Thesis , Inst. Agro.e tVét . HassanII , and University ofMinnesota . Eddebbarh A.,1988 . Séminaire C.I.H.E.A.M.L e lait dans larégio n Méditerranéenne, Rabat. Eddebbarh A.,1989 . Symposium ofDLG .Geisse n1989 . Guessous F.an dA .Eddebbarh , 1988. Seminar onth econstraint st o ruminants production inth etropics , Cairo. Hodges,J .1985 . Milk production indevelopin g countries. University of Eidinburgh. Nardone A.,an dE .Villa , 1990. International symposium on livestock inth emediterranea n cereal producing areas, Rabat. Yakhlef H.,1988 . Séminaire C.I.H.E.A.M. Rabat. Le lait dans là région méditerranéenne, Rabat.

88 The effects of environmental factors on water balance in animals

F.Valfrè ,V.M .Morett i &G.L .Magg i Istitutod i Zootecnica,Facolt à diMedicin aVeterinaria , viaceloria ,1 0- 2013 3 Milano -Itali a

Summary Water equilibrium in animals is strictly dependent on physiological functions involved in homeostasis and homeothermiaregulation ,an d on environmental factorstha t operate as stressors modificating saline and water replacement. The interaction between the efficiency of animal response to anomalous environmental condition and quality and disponibility of water sources,ar e factors affecting the productivity both in quantitative and in qualitative sense. Animal nutrition ison eo fth emos t important factors,an d as iti swidel y handling itwil l have anessentia l rolei n the next years, in which climatic changes could cause a reduction ofwate rresource s ofth eearth . Riassunto IIdelicat o equilibrio idriconegl ianimal i è strettamente dipendente da un lato dalle funzioni fisiologiche implicate nella regolazione omeostatica ed omeotermica dell'organismo, dall'altro da fattori ambientali che, agendo come stimoli piu o meno stressanti, intervengono nellevariazion i delricambi oidrico-salino . Le interazioni fra queste due entità ,1'efficienz a della risposta degli animali alle offese dell'ambiente, la disponibilité e la qualité délie risorse idriche di quest'ultimo,son o inultim a analisi fattorivincolant i la produttività degli animali sia in senso quantitativo che quaiitativo. Dei fattori ambientali 1'alimentazione è di gran lunga il più importante, ed essendo ampiamente maneggiabile dall'uomo, giocherà un ruolo essenziale negli anni a venire, nei quali cambiamenti climatici prospettano riduzioni dellerisors e idricheterrestri .

Introduction Beforedealin g withth e subject,i t isnecessar y to review somephysiologica l factorsconcernin g waterbalanc e inth e animal organism. It is common Knowledge that liquids in the organism are divided into : - watercontaine d inth ecells ,an d - waterpresen tbetwee nth ecells . 89 Most organism water is intracellular; this portion comprises three-quarters of the total, represents about 50% of the total body weight and does not move much. It can undergo only slight variations in total quantity and in composition of the solutions which it forms along with cellconstituents . Extracellular water, 20-25% of the total, is extremely variable. It includes all liquids except intracellular ones: blood, lymph, interstitial fluids, digestive, cutaneous and lacrimal secretions, eye humor,milk , urine andcerebro-spina l liquid. Extracellular water isdivide d intotw ocompartments : 1.th e water of the intestinal liquids which is about15 % oftota lbod yweight ,an d 2. the water of the blood plasma and lymph which is about 5%o ftota lbod yweight . Plasma liquid is more mobile than intestinal liquid, but they both can easily change their composition over a wide range, and affect each other throught the rapid exchange ofmetabolites . These exchanges occur throught the capillary wall, which is permeable to electrolytes but not to proteins of molecular weight over 20,000-75,000 or to compounds in suspension. The exchange between the interstitial and intracellular liquids is slower, due to the selectivity of the cell wall. Thus it is possible to affirm that the animal organism lives in water, indeed in "awate r current",an d itsflo wdepend supo n intake,losse san d exchanges between thedifferen tcompartment so fth eorganism . Therefore, replenishment has to be divided into "exogenous", strictly dependent upon drink water and that contained in feed, and "endogenous", namely water which derives from intracellular catabolism of carboydrates (55g/l00g of glucose), lipids (107g/100g) and proteins (41g/100g). The latter mechanism is particularly important because water so produced causes a reduction of molecular concentration in the cells, and thus recalls water from the intestinal contents, a role that exogenous water can notdirectl yhave . Electrolytes have an important role in the regulation of water flow and are present both in drink water and in feed; their daily intake is the primary condition for the regulation of osmotic pressure and the acid-base equilibrium, also in connection with daily losses of body fluids. The losses of water and electrolytes take place in differentways ,whic hd ono thav eth e samesignificanc e in thewate rbalanc eo fth eanima lorganism . The "normal" excretory path is urinary, while those carried out by cutaneous perspiration and exhalation are the principal factors for the homeostasis of body temperature. Furthermore, there are losses throught the digestive system, muscular work (with evaporation of water to compensate for excess-heatproduction )an d animal products 90 (870g/l milk is equal to 17 1 in dairy cows producing 20 1/day,twic eth eurinar y excretion). It is necessary to underline that even if there is no exogenous contribution, loss of water throught the different paths is steady and unavoidable. This is due to the poor water reserve available for the organism, although 70% of body weight is water, as mentioned earlier. Reserve water in the organism can be both interstitial and circulating. Theregulatio n ofwate rmovemen t inth eorganis m Strict and constant control of the water balance - inflow and outflow - is involved in homeothermia mechanism regulation; in fact homeothermia and water homeostasis appear atth e sametim e inphylogenesis . It is known that water equilibrium is controlled by physio-chemical,hormona l andnervou sfactors . The first factor regulates the exchanges of water and electrolytes between the compartments of the organism as mentioned above. Hormones have various roles in water and mineral replacement: it is sufficient to remember thyroxine, corticosteroids and catecholamines and all their direct and indirectactions . Nervous factors affect the water balance throught the "senseo fthirst "an dregulatin g vessel permeability. All these notions are mentioned since environmental factors affecting water replacement in animals act mediated by physio-chemical, hormonal and neuro-endocrine pathways,singl y or incombination . Environmental factors The most important factors will be mentioned, with some explanatory examples fora fe wo fthem . Considerations include: The climate, for its direct influence on thermoregulation and indirect influence on the alimentary supply ofwater . - The adaption of the animals to anomalous and/or new environmental situations;i nrespons e tostres s conditions some neuro-endocrine modification have an important significance forth eregulatio n ofwate rbalance . - The farming method and management, whether for the stress conditions that it can generate, or for corrective factors (i.e. livestock housing) to adverse climatic conditions. - Thetyp e of animalhousing ,i norde rt o supplywater ,t o provide careful breeding (environmental dampness due to washing in swine breeding) and to control temperature changes. - Thetyp ean d quantity ofproduct s (870g rwate r secreted for every litre of milk produced, 2.6 molecules of water binding toever y amino-group). Health condition and diseases, especially those affecting the various systems involved in water 91 replacement; the gut, liver, kidney and lungs (functional orspecifi c diseases). -Anima lnutrition . It is necessary to highlight the important role of nutrition, dealing first of all with drink water, which represents themajo rwate r contribution,an d thenwit h the portion fromothe r feed. Water:th e characteristics of drink-water representon eo f the most limiting factors, without calling into question pollution and industrial waste, so widespread in modern countries. It is enough to think of the variability of the salts dissolved in water, and to the fact that they are often different from those inanima l fluids,t o realizetha tth e difference in osmotic pressure causes problems for water replacement inanimals . Feed:th e following factorsshoul d be inconsidered : - the percentage of component and/or soaking water (dry feed,grass ,silag e feed,molasse s andwe t feed etc.); - the intakeo fN a andK an dthei rratio ; - the presence of micro and macro nutrients and their absorption; - the percentage of cellulose and its fractions, due to their influence on the intestinal absorption of water and electrolytes; - the use of binding agents due to the drastic role they have inregulatin g intestinalwate rflow . These factors areofte n neglected,especiall y incountrie s with well-developed animal husbandry, in which water resources are in general plentiful, and thus become of minorimportance . For over two years we have experienced reduced water availability. Control of the problem is now necessary, to avoid risks not only in the quantity, but also in the quality of animalproduction .

92 Effecto fhig htemperatur eo nproductio nan dqualit yo fBil k

V.Cappa ,L .Calamari ,P .Vazhapill y& E .Frazz i

Istitutod iZootecnica ,Facolt àd iAgrari aU.C.S.C ,Vi aEmili aParmen - se,84 ,2910 0Piacenza ,Italy .

Summary

Thehig henvironmenta ltemperatur e (above2 5 °C)ca nhav eeffect so n bovineorganism ,o nmil kproductio nan do nmil kquality .Th eeffect sca n be further aggravated if ahig hhumidit y isals opresent .Durin gth e summermonth s inth eP ovalle y hightemperature s causealteration si n milkwhic hi ntur ncreat eproblem si n"grana "typ echeese-making . Researches were carried out on cows present in the experimental stable of the Agricultural Faculty of Piacenza and in 4 dairy herds raisedi nth eprovince so fParm aan dMilan . The results obtained at Piacenza reveal that in the presence of rather high temperature (26-29 °C)an dhig h relative humidity'(65-90% ) therei sa decreas ei nfee dintak e (2-6%)an di nmil kproductio n (about 2.5%);a nincreas e inrecta lan dski ntemperatur e (about0. 5 and0. 9° C respectively), in respiration rate (about 47%); a reduction inmil k acidityan di nth econcentratio no ftota lCO ,o fblood .Th eresult sfro m 4dair yherd sconfir mth ereductio ni nmil kacidit yfro mhea tstres san d moreover reveala longe rtim efo rmil kcoagulatio n inth epresenc eo f renninan da les sconsisten tmil kcoagulum . Extradescriptors :dair ycows ,microclimate ,hea tstress ,mil kquality .

Introduction

It is already well known that high summer temperature influences negatively the production and reproduction performances of different animal species. The cattle, in particular dairy cows, are not an exception to this rule and already at temperatures above 25.5 °Ca reduction in feed intake and, in consequence, a reduction in milk productionhav ebee nnotice d (Harris1988) . The maintenance of milk production in high temperature environments isdetermine dmainl yb yth ebalanc ebetwee nmetaboli c heatproductio n and heat loss. Metabolic heatproduce d in itstur n isrelate d toth e quantity ofmil k secreted andt oth ehea t production associated toth e maintenance (Flamenbaum etal . 1986). Therefore the highproducer sar e those who have more difficulties in hot climates to maintain body temperaturei nnorma llimits . Animals react to these unfavourable environmental conditions by increasing the heat loss through processes of evaporation which is mainly represented by sweating and increased respiration rate (Harris 1988). Sincedair y cowsar eno talway sabl et oeliminat ehea tproduce d inexcess ,i norde rt omaintai nth emil kproductio nunaltered ,differen t types of interventions havebee n adopted. Among them those gavemor e favourableeffect sare :shad et oreduc eth eradian thea tfro msk y(Igon o et al. 1987), forced ventilation (Berman et al. 1985), artificial cooling (Chiappini 1988), administration of chilled drinking water (Wilkse tal . 1990),an da suitabl efeedin gtechniqu e (Harris1988) .

93 Actualstat eo fKnowledg e

Theproble m isno t of secondary importance because of itseconomi c bearing. This is evident from the numerous researches done on the subject in the last decades. Mostly all works are centered on the effectso fhig htemperatur eo nmil kproductio nan dreproductio n (Collier etal . 1982,Fugua y 1981,Sharm ae t al. 1988,Wilk se tal .1990) .Onl y fewhav e studiedth eeffect so nmil kcompositio n (Sharmae t al. 1988), onchemico-physica l characteristics amongwho mth e acidity (Fossaet . al.1984 )an do nmil khygen ewit hsomati ccel lcoun t (Igonoe ta l1987) . In the Italian context the milk characteristics have particular importancedu et othei r effectso n cheesemakin gproces s aboveal lfo r cheeseswit hlon gripenin gperiod . According to some studiesth emil k produced inth e summarmonth si s lessadap tfo rcheese-makin g forit slowe rtitratabl eacidit y (Cappae t al. 1989)an d forlonge rtim eo f coagulation (Fossae t al. 1984). This may be due to the effects of high summer temperature on the physiologicalstat eo fth eanima lan dma yals odu et oth efeed suse di n thatperiod . In factth enatura lenvironmen t (theclimate )an dtha to f theshelters ,bot hfree -an dtiestalls ,(th emicroclimat e )of, .P ovalle y presenthig htemperature sdurin gth esumme rwit hmean sabundantl yabov e 25° C(figur e1 )an dwit hpeak sgoin gabov e3 0°C .Ofte nth etemperatur e

PiacenzaMilan oBologn a

Temperaturx e*C Figure 1. Mean hourly temperature in 3 localities of Po valley in the month of July from 1970 to 1985. Data from GiuliacciM .1988 .

0 2 4 6 8 101 21 41 61 82 02 22 4 Hourso fth eda y

inside the shelter, particularly in those closed, is a few degrees higherwit hrespec tt oth eoutsid etemperature .Th erelativ ehumidit yi s equallyhig h (above70% )an dtogethe rwit hhig htemperatur ei sth ecaus e ofsignifican tquanti-qualitativ evariation so fmilk .

Experimental lavou t

During the course of the last two years (1987/1989)researche swer e carriedou ta tou rInstitut efollowin gtw odirections :on eutilizin gth e cowspresen t atth e experimental barn stall ofth e Institute andth e other controlling 4dair y herds raised inth eprovince s of Parmaan d Milano fwhic h 3 freestalltyp e and 1tiestal ltype .I nal lcase sth e cowswer eo fItalia nFriesia nbree dwit hmedium-hig hproduction . Inth etrial scarrie d out atth e experimental stall, 8 cowspresen t were subdivided into two groups sufficiently homogenous for milk production and lactation stagean dwer epu t intw o sectorso f thesam e barnstal ldifferin gfo rtemperature . 94 More precisely in the first trial done in Spring 1987 the mean temperarturedurin gda ytim ewa s26-2 7° Ci non esecto r and22-2 4° Ci n theothe r sectorwit hrelativ ehumidit y of 74-90%. Inth e secondtria l ofSprin g198 8th emea nda ytemperatur ewa s26-28. 6° Ci non esecto ran d 22-25.9 °C in the other sector but with a more contained relative humidity (65-82%). The ration for all cows was constituted of hay ad libitum, corn silage (14-18k g as fed)an d concentrate feedwit h 20%crud eprotei n givenaccordin gt oproduction . The controls carried out regarded feed intake;mil k production and chemico-physicalcharacteristic s ofmil k (pH,titratabl e acidity, fat, totalprotein , lactose,Ca ,P ,Mg ,N aan d K); atbloo d levelmetaboli c profile,som ehormone s (insulin,Cortisol ,T ,an dT^ )an dtota lCO z;th e rectalan dski ntemperatur ean drespiratio nrate . Thecontrol sexecute da t4 dair yfarm sregarded : - internaltemperatur ean drelativ ehumidit yi neac hstabl e - feed samples collected periodically and subjected to chemical analysis - milk samples collected from tanks at 15-20 days intervals and individualmil k samples from 10-15cow stake n fora tota lo f 2-5 times according to each farm. On samples collected fat, total protein, lactose, pH, titratable acidity, creaming capacity, naturalcreamin gan dtromboelastogra mwer edetermine d - blood samples,take no nth eoccasio no fth eindividua lmil ksampl e collection,fo rth edeterminatio no fmetaboli cprofil ean dhormone s T,an dT, . Thesecontrol swer ecarrie dou ti nJune-Septembe r1989 .

Results Trials at the experimental stall of the Institute The cows present inth e higher temperature sector had a different behaviour for somemetabolic-physiologica l aspects and milk production withrespec tt oth ecow si nth elowe rtemperatur esecto r (table1) .

Table 1.Mea n valueso f someparameter s intw o groups of cows inth e trialsconducte da tth eexperimenta lstabl eo fth eInstitute .

Sectoro fhighe r sectoro flowe r Difference temperature temperature

Rectaltemperatur e(°C ) 39.3 38.7 + 0.6 Skintemperatur e (°C) 37.6 36.7 + 0.9 Resp.rat e (cyclesmi n ) 67.0 45.0 + 22.0 Milkacidit y (°SH50ml" 1) 3.3 3.6 - 0.3 Totalbloo dC0 2 (mmol1 ) 20.0 24.0 - 4.0

In the hoter sector dry matter intake decreased slightly (2-6%)an d milk production also decreased a little (about 2.5%) but without significantvariation si nth ecomponents . Reduction in feed intake and inmil k production have justifications in the physiological parameters related to body temperature and respiration rate whose differences aremor e evident inth e afternoon hourswhe nth etemperatur ei nth eshelte rreache dit smaximum . 95 Difference of about 0.5 °Cwa s observed between the groups inth e hoter andothe r sector forrecta ltemperatur e (39.3v s38. 7 °C)an d0. 9 °Cfo rski ntemperatur e (37.6v s36. 7 °C). Respiration ratewa s higher incow s of the hoter sector with amea n of 22 cyclesi nmor epe rminut e (67v s45 )wit hrespec t toth e cowsi n the other sector. Thepulmonar y hyperventilation may explain the lower acidity observed in the milk (3.3 vs 3.6 °SH). This result was not reconfirmed inth e second trialwher e therelativ e humidity was lower. It is not yet clear by which mechanism the milk acidity is reduced. Probablyth erespirator yalkalosi sfollowin ghyperventilatio n seemt ob e the principal cause. Infact, during the respiratory alkalosis the capacity ofbloo dt obin d CO.i sreduce d (Colliere tal . 1982). Inthi s condition there seem tob e ahighe r urinary excretion of HCOji norde r to keep the ratio between HCO,an d partial pressure of C02 in blood unchanged (Schneider et al. 1988). It is not to be excluded that a reduction takesplac e inth eexcretio n ofCO ,dissolve d throughmilk . Such a reduction could be one of the reasons of lower milk acidity during summer period. The above mentioned hypothesis could find confirmation fromth e lower levelso ftota l C02 found inth ebloo do f cowskep t inth ehote rsecto ro fou rtrial . Atbloo d level nosignifican t differencewa snotice d forparameter s of metabolic profile controlled. Alsothe.'hormone s (insulin, Cortisol, T,an d T,) di d not show any significant difference between thegroups , but anyhow T,an d T,i nth e afternoon controls resulted tob e loweri n thegrou pkep t inhote rsector . Trials carried out in 4 dairy herds Thedat ao fth e analyseso fmil k andbloo d samples are stillunde r elaboration and therefore,a tthi smoment , it ispossibl e only togiv e someindication swhic har epresente dpartl yi nth etabl e2 .I ntha tmor e

Table2 .Mea ntemperatur e andrelativ ehumidit y of4 day sbefor emil k samplingan dsom emil kcharacteristic si non eherd .

Milk Sampling Internal Int.rel. Acidity Coagulation date Temp.(°C ) hum. (%) (°SH 50ml"1) r (min)a3 0 (mm)

2 June 20.31 58.82 3.53 14 31 22 June 23.55 62.57 3.51 14 31 7 July 22.07 79.88 3.58 15 28 25 July 25.44 55.07 3.29 19 15 8 August 24.87 74.39 3.55 12 35 important results fromon eher d isgiven ,whic h intur n resemblesmor e orles sth edat ao fothe r3 herds . In correspondence to the higher temperatures registered in the sheltersther ewa sa reductio ni nmil kacidit y andmil k samplesha da longercoagulatio ntim ei nth epresenc eo frenni nan dles sconsisten t coagulum (longerr an dshorte ra 3 0value so ftromboelastogram) . Duringth esam eperio di nbloo dther ewa sa reductio ni nth eleve lo f T,an dT 4a si twa sobserve db yothe rauthor s (Wilkse t al. 1990).Wit h allprobabilit y this happens asa consequenc eo f reduced feed intake which lowers the thyroid activity, but may be also due to a direct effecto fhea tstres so nth eorganism .

96 Conclusions

The results obtained from these researches confirm largely what has beenobserve d byothe rauthor so ndair y cowskep t inho tenvironments , in particular, those regarding the variations in rectal and skin temperature, respiratory rate, reduction in feed intake and inmil k production.Moreove rsom eeffect so fhea tstres so nmil kquality ,namel y lower acidity, longertim eo fcoagulatio n and less consistentcoagulu m havebee nbrough tint oevidence .I ti sclea rtha tthes echemico-physica l modificationshav erepercussion so nchees-makin gprocesses .

References

Berman.A. , Folman.Y. , Kaim.M. ,Mamen. ,M. ,Herz .Z. ,Wolfenson .D. , Arieli.A . SGraber .Y. , 1985.Uppe rcritica ltemperatur ean dforce d ventilation effects for high-yielding dairy cows in a subtropical climate.Journa lo fDair yScienc e68 :1488-1495 . Cappa.V. ,Vazhapilly .P. ,Maianti .M.6. ,Lombardelli .R . &Frazzi .E. , 1989. Effetti delle variazioni ambientali (microclima) sulle performancesd ivacch ed a latte.Scienz ae Tecnic a Lattiero-Casearia 40:98-115. Chiappini. U., 1988. II raffrescamento artificiale ne£ ricoveri zootecnici.Geni oRural e51:27-30 . Collier.R.J. ,Beede .D.K. ,Thatcher .W.W. ,Israel .L.A .& Wilcox .C.J. , 1982. Influenceso fenvironmen t and itsmodificatio n ondair y animal healthan dproduction .Journa lo fDair yScienc e65:2213-2227 . Flamenbaum. I.,Wolfenson .D ., Mamen .M . &Berman .A. , 1986.Coolin g dairy cattleb y acombinatio n of sprinkling and forced ventilation and its implementation in the shelter system. Journal of Dairy Science69:3140-3147 . Fossa. E., Pecorari. M. &Mariani . P., 1984. Variazioni stagionali dell'acidità e delle caratteristiche di coagulazione del latte. L'industriade llatt e20(l):87-97 . Fuquay.J.W. , 1981.Hea tstres sa si taffect sanima lproduction .Journa l ofAnima lscienc e52:164-174 . Giuliacci. M.. 1988 .Climatologi a fisicae dinamicadell aValpadana . E.R.S.A.Servizi oMeteorologic aRegionale ,Bologna ,76 . Harris. B., (Jr). 1988. These practices help prevent summer slump. Hoard'sDairyma n173(12):57 9& 588 . Igono.M.O. ,Johnson .H.D. , Steevens.B.J. , Krause.G.F . &Shanklin . M.D., 1987. Physiological, productive, and economic benefits of shade, spray,an d fansyste mversu s shade for holstein cowsdurin g summerheat .Journa lo fDair yscienc e70:1069-1079 . Schneider. P.L., Beede. D.K. & Wilcox. C.J., 1988. Nycterohemeral patterns of acid-base status, mineral concentration and digestive function of lactating cows in natural or chamber heat stress environments.Journa lo fAnima lScienc e66:112-125 . Sharma.A.K. , Rodriguez.L.A. , Wilcox.C.J. , Collier.R.J. , Bachman. K.C. &Martin .F.G. , 1988.Interaction so fclimati cfactor saffectin g milkyiel dan dcomposition .Journa lo fDair yScienc e71:819-825 . Wilks.D.L. ,Coppock .C.E. ,Lanham .J.K. , Brooks.K.N. ,Baker .C.c .& Bryson. W.L., Elmore. R.G., Stermer. R.A., 1990. Responses of lactating holstein cows to chilled drinking water in high ambient temperatures.Journa lo fDair yScienc e73:1091-1099 . Wolfenson.D. ,Flamenbaum .I . &Berman .A. ,1988 .Dr yperio dhea tstres s reliefeffect so nprepartu mprogesterone ,cal fbirt hweight ,an dmil k production.Journa lo fDair yScienc e71:809-818 . 97 Heatstres seffect so nsom ebloo dparameter so fshee p

G.Bertoni ,U .Bernabucc i& Filipp iBalestr a6 .

Istitutod iZootecnica ,Facolt àd iAgrari aU.C.S.C. , 29100Piacenza .

Summary

Togiv ea contributio nt oth eevaluatio no fth ehea tstress ,tw otrial s arebee n carried out on sheep (shaded =S o runshade d =US )wit hth e main aim to measure blood changes during heat stress or after night cooling. The results,quit e contradictory, seem to confirm that heat stress influencesbloo d dilution and osmolality, but alsoglucose ,T, , insulinan dCortiso lvalues .Nevertheles s fora bette runderstandin go f suchbloo d indices,th ene wresearche smus tb eperforme dwit hcar et o avoidstrang eeffect s (i.e.feeding ,othe rstress )durin ghea tstress . Extradescriptors :hea tstress ,sheep ,metaboli cprofile ,hormones .

Introduction

So far heat stress seems tob e oneo f themor e intriguing factors making difficult animal production of many world areas. In fact the animals can adapt to the hot climate, nevertheless the response mechanisms are helpful to survive but are detrimental to performance (Webster 1976). Iti sals owel lknow ntha t somespecie san dbreed sar e morehea ttolerant ,therefor ether ewoul d beenoug hvariabilit y tob e utilized for suchgeneti c improvement (Finch,1984) .Nevertheles sth e selectiono fhea ttoleran t subjects,perhap sthos ecapabl et omantai n normal rectal temperature under agive n heat stress condition (Hopkins etal .1978),i smad edifficul tb yman ystrang efactors ,i.e .respiratio n disturbances, previous heat adaptation etc. (Hopkins et al. 1978). Therefore the need exists for new physiological indices of heat tolerance (Johnson1982) ,lik ebloo dparameters .Nevertheles si tmus tb e noticed thatth ewel lknow n changeso fthyroi d hormones,Cortisol ,GH , insulin, glucose, electrolytes etc. are in fact very questionable becauseman y contradictory resultsar ereporte d inth e literaturean d mainlydu et odifferen texperimenta lcondition s (adaptedanimal so rnot , rate of temperature changes, continuous or temporary heat stress, humidity andventilatio n changes,physiologica l and feedingconditions , frequencyan dwa yo fsampling )(Webste r1976 ;Hopkin se tal . 1978). Considering suchlimit so fth eavailabl eknowledge san dth efac ttha t in hot climate the shadowing seems capable to improve the animal performances (Vermorel 1987), itha sbee ncarrie dou ta seri eo ftrial s withth eai mt oclarif ywhethe rth edirec texpositio no fyoun gshee pt o thesu ndurin gth esumme rca nmodif ysom ephysiologica lresponse sand/o r bloodparameter so ftw obreeds .Furthermor ewhethe rth emeasurement sa t different times:afte rth enigh tres t or duringth e heat stress climax couldimprov eth epossibilit yt ounderstan dth eanima lresponse .

Materialsan dmethod s

Thetrial swer ecarrie dou tdurin gth esumme ro f198 7an d198 8t oth e experimentalfar mo fth eViterbo' sUniversity . Firsttria l (1987): twohomogeneou sgroup so f 7Sarda' s lambseach , 98 aged5 month sapproximatel yan dwit ha naverag ebod yweigh to f18-2 0kg , werekep t (from2 8Jul yt o1 8September )i ntw oseparat e pens: - shaded (S):provide do fa larg e roofedare a - unshaded (US): withoutan ykin do fshelter . A commercial concentrate,hay , and good quality water,wer e supplied freely and the intake controlled weekly. Every 7-14 days the animals were weighted and blood samples were withdrawn (at 8.00 and 16.00), rectal temperature and respiration ratewer e alsomeasure d at8.0 0 and 16.00(suc hcheck swer edon ei na sequenc et oavoi dan ystress) . Second trial (1988):ther ewer e fourgroup so f 7lamb seach ,2 of Sarda'san d2 o fComisana' sbree dwit ha bod yweigh to f24-2 6k gfo rth e Sarda and of 29-31 kg for the Comisana, at an age of 9 months approximately. The 4 groups were all provided with a roofed area, neverthelessth e2 group so feac hbree dwer edivided : - shaded (S):th eroofe dare awa salway savailabl e - unshaded (US):roofe dare awa sinterdicte dbetwee n8.0 0an d20.00 . Hay and waterwer e freely available,whil e concentratewa s fed ata rateo f20 0g/head/day .Averag e hayan dwate rintak ewa smeasure dever y week aswel l asth ebod yweight .Ever y 14days , rectaltemperature , respirationrat ean dbloo dsample swer etake ni nth emornin g (7.30-8.00) andafternoo n (15.00-15.30)takin gcar et oavoi dth estres seffects . Inbot htrials : / - blood (Li-heparin)wa simmediatel ycentrifuge a (exepta smal laliquo t forPVC )an dplasm adee pfroze n(-20° )befor et operform eth emetaboli c profileanalysi s (Calamarie tal .1989 )a swel la sth eRI Aevaluatio no f T,,insuli nan dCortiso lan dth eosmolalit ymeasuremen t (Gonotec) - anautomati c stationha sgive nth eT °an drelativ ehumidit ya thourl y intervals,wher etota lradiatio n (cal/cm) wa sals ogiven . Statistical evaluation of the data was carried out with the covariance 3 factors of classification: time, treatment and hour of sampling forth e1s ttria l (SAS 1990),whil eANOV A (3criteria :time , breed and treatment) was used forth e 2nd one. Correlations between differentparameter san dmeteorologica ldat awer eals overified .

Resultsan ddiscussio n

Inspit eo fth etw otrial sar ebee nquit edifferent ,i tseem susefu l tou st odiscus sth eresult sal ltogether .Howeve ri tshoul db eremarke d in advance that in the first trial the US (unshaded) animals were exposedt osu ndurin gth eday ,an dt oope nsk ydurin gnight ;furthermor e themeteorologica lcondition swer emor eextrem ei nth e1s ttria l(Figur e 1). Therefore it isno t surprising if theu s of the 1st trial have shown a lower feed intake (of 300-400 g/d as dry matter, mainly concentrate)an dhighe rwate rintak e (2.5-3.51/ dvs .1.0-1.7 )whil eth e weightgai nwa sa significantl ylower ,compare dwit hth eS (shaded ) •C Maxl'i^ 'c Mint'"" 3S| |3 5 1988 30 ::] r> 0 R 0 : n 13 R ' 30 • 25; |: 25 20: : t j 20 15H I j I j i 15 BBHBBBBBSBI IO 7 +1+ 2 -2-101234567 -2-10123456 20/9 Weeks 20/9 29/6 Weeks Figure 1. Average weekly temperatures observed along the 1st trial (1987)an dth e2n don e (1988). 99 animals.Suc heffects ,tha tar ebee nmuc hles seviden t inth eSarda' s lambs of the 2nd trial, arewel l correlated with the meteorological parameters and are ingoo d agreement with thewel l known effectso f heat stress (Bianca 1965). Theresult sar eals o inaccordanc ewit hth e positiveeffect so fshadin g (Vermorel1987 )whic h aremor eeviden ti n the1s ttrial ,bu tar eimportan ti nth e2n dto oan dparticularl yfo rth e reproductive activity because the oestrus cycle (by progesterone variations)wa smor eregula ri nS animals ,i.e .83 %fo rComisan aan d50 % forSard avs .0 % forComisan aan d 50%fo r Sarda (unpublished results). In this last trial the lambs of the Comisana has shown a different behaviour than those of Sarda (Nardone et al. 1990) and this could confirmtha tth eshee pbreed sar emor eo rles shea ttolerant . Beforet otal k aboutbloo dvariation s itmus tb epointe du ptha tth e animals were yet accustomed to high temperature (Figure 1) and that Viterbo's climate isdry-ho t (relativehumidit y of 15-25% atnoon )an d the temperature tend to drop quickly late afternoon (the day/night excursionwa salway sgreate rtha n 14°C,Figur e 1).Therefor e itca nb e easilyunderstoo dth enorma lvalue sobserve d forrecta ltemperatur ean d respiration rate inal l animals atth emornin g checks,whil e inth e afternoon therespiratio n ratewa sver y high and similar between san d USbu thighe r forth eSarda' sanimal s (140-160pe rminut evs .120-130) . Suchrat eseem st ob eth emaximu man dtherefor e can justifyth esligh t raiseo frecta ltemperatur ei nth eU Svs .S an dComisan avs .Sarda . In spite of we have shown that heat stress could be considered relativelyhighe r inth e1s ttria lan di nth eU Sanimals ,th ejudgemen t concerningth ebloo dvariation sappea rver ydifficul tmainl ydu et oth e contradictory resultsobtaine dwit hth etw otrials .Nevertheless ,i fw e excludeurea .Ca ,Pi ,M gan d Znfo rwhic h itseem s impossiblet ofin d any link with the heat stress, our results permit some useful observations.Th eprotei nfraction s (aswel la sth eenzymes )see mt ob e increasedb yth ehea tstres si nth e1s ttrial ,otherwis ei nth e2n dthe y arereduced ,particularl y inth eafternoon ,an dver yofte nnegativel y correlated (atleas t *)wit hth eexterna l T°an dth egloba lradiation . Only the last results are in agreement with those of Kamal et al. (1989), i.e. heat stressan dwate r available seemt ocaus ea nincreas e ofth e blood volume and itsdilution . It istherefor e interestingt o showstha tNa ,K ,C Ian dosmolalit yar eincreased ,ofte nsignificantly , inth eafternoo no fS an dU Sanimal so fth e2n dtrial .Furthermor ethe y arepositivel y (* or **)correlate dwit hT °an dtota l radiation; iti s thenpossibl etha tsuc hconcentratio nrais ecoul db eth ewa yt oincreas e thebloo dvolum e (witha protei n dilution). Iti sals ointerestin gt o notetha ti nth e1s ttria lonl yK an dC Iha dth esam ebehaviou rwhil eN a (andpartl yosmolality )wa sreduce d (*) inth eafternoo nbu tonl yfo r the first 3weeks .I fw e considertha tBianc a (1965)assert stha thea t stressinvolv ea reductio no fN aan dK whil eother sdi dno tobserv ean y change of Na and osmolality, it can be ^assumed that different experimentalcondition sar eth emai ncaus eo fsuc hcontradictions . Glucose is always higher in the 1st trial (4.7-5.5 vs. 3.5-4.5 mmol/1)a sth econsequenc eo fth ehig hconcentrat ediet ,howeve ri nbot h it is lower (*) inth eU S animalsbu t only forth emornin g sampling. This is in agreement with Bianca (1965), but not with Sano et al. (1983), nevertheless it must be considered that feeding is also an important confusing factor, thus the afternoon values are higher or lowertha nth emornin gones .Howeve r thevariation so fglucos eshow ni n theafternoo nsee mpartl ydu et oth ehea tstress .I nfac tinsuli n (also higher inth e 1sttrial )i salway s lowerwhe nth emornin g valueso fU S animalsar econsidere d (Figure 2);otherwis ei nth eafternoo nit s 100 INSUUN(mcU/ml ) 2.0 T3(ng/ml ) CORTISOL(ng/ml ) K 32 1.8 32 «28 1.6 »^ 28 • «2 4 1.4 24 T .<*>- ,*> *Oj 20 «20 1.2 •M&£-— 16 •o 16 '*""s.. „...«-*••"'' «1 2 1.0 '"'•••••"•""' 12 o> 8 29.4'30.6' 33.4* i»T 33.6'C 0.8 29.4*30.8 ' 33.4* 33.6*C 8 29.4' 30.6' 33.4' 33.6'C . , »r. 32 2.0 00 1.8 32 00 28 28 0) ?4 1.6 24 20 1.4 20 V ^» •*. « 1.2 •o 16 •^ 16 w—Y-,, 12 ^ 1.0 12 (0 8 «r 0.8 8 r CO co 32 28.6'30.6 ' 28.»' 30.2'26.2' C 28.6'30.6' 2».»' 30.2' 25.2'C 32 |28.6'30.6- 29.9* 305* 25.2*C 2 28 28 «2 4 24 §2 0 20 1 «1 6 16 E1 2 1? U^ 0ft 8 :::ï?:^^^^^ 0 8 01 2 34 5 6 7 12 34 5 6 7 01 2 3 4/567 Weeks Weeks Weeks Figure 2.Hormona l behaviour inshee p exposed toth esu n (morning..g.., afternoon 0-•-)o rshade d (morning—•—, afternoon « ). Themaximu m T° valueso fsamplin g daysar eals o reported.

behaviour is much more changeable. Because insulin is positively(*) correlated with glucose itmean stha tth elas t influences theforme rbu t insulin seems to be affected also by other factors i.e. adrenaline (Vermorel, 1987)an d that could explain the low "r" values and the variableness. Triiodothyronine (Tj) and Cortisol have also shown to change ina n unpredictablewa y (Figure 2): a)T ji s lower inth eU S animals (significantly only inth emorning ) of the 1sttrial ,whil e there aren odifference s inth e2n done .Therefor e this is partly in agreement with many reports showing that heat stress produce a reduction of the thyroid activity (Bianca 1965; Vermorel 1987). However inth eafternoo n theT ,value s arealway s higher (except S Comisana) than inth emornin g and also higher inth eU Svs .S fo rth e Sarda ofth e2n d trial. It is thus confirmed that the feed intake is very important forthyroi d secretion, as supposed by Bianca (1965)an d as we have elsewhere demonstrated. It istherefor e understandable that in some experiments, maybe with fewcar e in sampling respect tomeals , the thyroid hormones would be unchanged or surprisingly increased even if forT 3onl y (Acevese tal . 1987), byth ehea t stress b)Cortisol, lower in theU S animals inth e morning (* or ** forth e Sarda), inth eafternoo n itha sa very different behaviour between the breeds: i.e.th eSard a hasshow n an increase forth eU San dvicevers aa decrease forth eS ,whil eth eComisan a remained almost unchanged inbot h groups (orslightl y increased inS) .I t iswel l known that Cortisol is increased with an acute heat stress and reduced with a chronic one (Webster 1976), weca nsuppos e that inman y cases,an dparticularl y for the US Sarda's lambs,th e long exposition to heat stress,bu t forfe w hours each day,d o notproduc e any important adaptation. However iti s difficult tosa ywhethe r iti sa nadvantag eo rnot .

101 Conclusions

The results ofou rtrial s arebee nto ovariabl e topermi t anyrea l conclusion, this because the experimental conditions were not enough extremet o induce atru e heat stress (infac tbloo d values andothe r physiologicalparameter swer eno tdramaticall ychanged) .Nevertheles sw e have showntha t the shadow could be very useful and that Sarda and Comisana seemdifferentl y tolerantt oheat ;furthermor ew ehav eshow n thatsom ebloo dparameter swoul db eusefu lfo ra bette runderstandin go f suchproble ma swel la sindice so fth ehea ttolerance .Howeve rthe ynee d tob e checked inwel l standardized conditions (mainly from the feeding pointo fview ,i.e . feedscoul db eoffere ddurin gth ecoolin gperiod , butals ofo rothe rstres scauses )an dabov eal lalon gth ehea tstress .

References

Aceves, C., Romero, C., Sahagun,L . SValverde-R , C, 1987.Thyroi d hormone profile in dairy cattle acclimated to cold or hot environmental temperatures. Acta Endocrinologica (Copenh) 114:201-207. Bianca,W. ,1965 .Cattl ei na ho tenvironment .J .Dair yRes .32:291-345 . Calamari,L. ,Bertoni ,6. ,Maianti ,M.G .& .Capp aV. ,1989 .Sull autilit à di nuovi parametri ematochimici nella valutazione del profilo metabolicodell elattifere .Zoot .Nutr .Anim .15:191-210 . Finch,V.A. ,1984 .Hea ta sa stres sfacto ri nherbivore sunde rtropica l conditions. In:Herbivor e nutrition in the sub-tropics andtropics . Ed.Gilchrist ,M. ,Th eScienc ePress ,Craighal . p.89-102. Hopkins,P.S. ,Knights ,G.I .& L eFeuvre ,A.S. ,1978 .Studie s ofth e environmental physiology oftropica l Merinos.Aust .J . Agric.Res . 29:161-171. Johnson, H.D., 1982.Rol e of physiology in cattle production inth e torpics. In:Anima l production in the tropics. Ed. Mohamed K.Y., Praeger,Ne wYork .p.3-28 . Kamal,T.H. ,Habeeb ,A.A. ,Abdel-Samee ,A.M . &Marai ,I.F .1989 .Mil k production of heat-stressed friesian cowsan dit simprovemen t inth e subtropics. In: Ruminant production in the dry subtropics: constraintsan dpotentials .PUDOC ,Wageningen ,p.156-158 . Nardone,A. , Ronchi, B.,Valentini ,A . 1990.Effec to f solarradiatio n onwate r and food intakean dweigh tgai ni nSard aan dComisan afema l lambs. In: Proc. International Symposium animal husbandry inwar m climates.Viterbo ,Italy ,27-28-2 9Octobe r (inpress) . Sano, H., Takahashi, K., Ambo, K. & Tsuda, T. 1983. Turnover and oxidationrate so fbloo dglucos ean dhea tproductio ni nshee pexpose d toheat .J .Dair ySei .66:856-861 . SASINSTITUT E INC.,1990 .SA Suser' sguid e statistics,versio n 6.Ed . SASInstitut eInc .Cary ,N.C . Vermorel, M. 1987.Effect s of climatic conditionso nenerg ymetabolis m andperformanc eo fcalves .In :Energ ymetabolis m infar manimals .Ed . Verstegen, M.W.A., Henken, A.M. Martinus Nijhoff, Dordrecht. p.180-198. Webster, A.J.F. 1976. The influence of the climatic environment on metabolism incattle .In :Principle so f cattleproduction .Ed .Swan , H.,Broster ,W.H. ,Butterworth ,London ,p.103-120 .

Agran tfro mMP I40 %i sacknowledged .

102 Effectso f high températures on reproduction in small ruminants

S.Casu,P.Cappai , S.Naitana*

Istituto Zootecnico eCaseari o per laSardegna . 07040 Olmedo (SS) * Istituto di Fisiologia Veterinaria. 07100 Sassari

Summary

High temperatures play a major role among the various environmental factors affecting reproduction in small ruminants. Their influence is closely linked to the increased body temperature induced in these animals. In the ram and the billy-goat, libido and semen quality have been shown to decrease, with differences between breeds and between single animals.Th e greatest damage iscause d during the first stages of spermatogenesis with delayed effects on fertility. In the ewe, high temperatures affect the oestrus: they reduce its length or sup­ press it depending on the moment when heat exposure takes place. In contrast, in the goat high temperatures make the oestrus cycle lon­ ger. Furthermore, in these species heat stress has harmful effects upon ovulation, while in the ewe the greatest damage is observed in the stages immediately followig ovule fecundation. In the ewe, expo­ sure to heat in the last stage of gestation causes glandular and ske­ letal impairments and a decrease in birthweight and lamb viability. This damage isbelieve d to be caused by a decreased blood flow to the uterus, a not fully developed placenta and changes in hormonal syn­ theses. The effects of high temperatures on reproduction, observed particularly in tropical areas, seem to exist in the Mediterranean areaa s well.

Keywords: ewe;goat ;hea t stress; reproduction; fertility.

Temperature plays a major role among the various environmental fac­ tors affecting reproduction in small ruminants. Unfortunately, in the last few years research in this field has been somewath neglected, maybe because high temperatures, causing the most depressive effects, are unlikely to be reached under our climatic conditions. For this reason, available data are few and not very recent, in particular as regards goats. The purpose of this paper ist o make abrie f review of the main information available concerning both sexes, in order to evaluate the need for new studies on the effects of high temperatures

103 and heat stress on reproduction in ewes and goats under our husbandry condition.

1.Mal e

1.1 Influence of high temperatures on sexual activity

Several authors report that in sheep the males sexual desire de­ creases during summer and sexual activity is more or less markedly reduced. Although Sukla and Bhattacharya (1952 a,b) note aprogressi ­ ve deterioration of semen quality from spring to summer in sheep and goats beloging to Indian breeds, they report no reduction in sexual activity. In a study carried out in Australia in hot-rooms, Lindsay (1969 )check s the sexual activity of Merino, Dorset Horn and-Border ramsunde r going weekly sperm sampling using an artificial vagina un­ der temperature conditions of 27° C to 43'C (weekly increase of 6-7 degrees and subsequent similar decrease after reaching the peak value of 43°C). He shows differences between breeds in some reproduction parameters: sexual activity, which is measured according to the num­ ber of ejaculations in an 8 hour period with hourly sampling is not affected by uigh temperatures, particularly in Merino rams. In con­ trast, in rams belonging to the other two breeds the number of ejacu­ lations is shown to decrease at the highest temperatures and to in­ crease when the temperature is lowered .Thi s phenomenon ismor e evi­ dent in the Dorset Horn than in the Border Leicester. The reaction time (i.e. the interval in seconds between the ram entering themoun ­ ting area and ejaculation) is also affected by temperature depending on breed: in the Merino, high temperatures are immediately reflected in the length of reaction time and normal values are restored with the temperature decrease, while in the other two breeds the effects are more marked two or three weeks after treatment at the highest temperatures. According to this author, the role played by photope- riodism in the reduction of rams'sexual activity in late spring or summer may be enhanced by high temperatures: one or two hot days may favour the beginning of a prolonged period of reduced sexual activi­ ty, particularly in some breeds. These observations could be linked to the notes by Casu et al. (1981) concernig the behaviour of Ile de France and Berrichon rams. In Sardinia they are used during summer for natural mounting and show a reduced sexual activity compared to Sardinian rams. Thus, high temperatures are added to other negative environmental factors (feed quality, water shortage, etc.) which ac­ count for the difficulties in the use of some North European breeds under Mediterranean breeding conditions (Folchan d Rocha, 1981).

104 1.2 Influence of high temperatures on semen quality

Several studies clearly show that high temperature, exceeding 29°- 30°C, affect sperm quality in the ram, producing changes in mass mo­ tility, the rate of live spermatozoa and an increased number of ab­ normal cells.Thes e phenomena are mainly linked to an increase inte ­ sticular temperature (cryptorchid animals are known to be azoosperma- tic) that can be induced by direct testicular heating or by high tem­ perature treatment in hot-rooms, but may also result from unnoticed febrile conditions. Exposure to high diurnal temperatures for several days under natural breeding conditions (Cheminau et al., 1990) may equally bring about effects similar to those in hot-rooms. From a morphologic point of view, all the parts of spermatic cells, particu­ larly the apical part, may be involved, with an increased rateo f pi­ riform heads, acrosome changes and tail-less spermatozoa (Dutt and Hamm, 1957 - Moule and Waites, 1963 - Rathore, 1968, 1969 - Kathore and Yeates, 1967). Spermatozoal degeneration occurs at a very early stage of development in seminiferous tubules (Braden and Mattner, 1970 -Waite s and Ortavant, 1968), while no damage isdetecte d if the heat-stress is suffered when they are in the epididymis (Howart, 1969). Smith (1971) thinks that in the ram short'exposure s to high temperatures for several days under field conditions may cause a sperm degeneration similar to that in hot-rooms with continuous heat exposure. Semen begins to deteriorate during the second week follo­ wing heat treatment and keeps low up to the fourth - fifth week. The recovery of normal fertility values depends on the intensity and the length of the heat stress and takes 50 to 60 days. 29°-30°C for two days are sufficent for an increased in the rate of abnormal spermato­ zoa (Colas, 1980). In addition to the different responses to high temperatures between ram breeds (Lindsay, 1969), differences between single animals have been reported, suggesting a genetic contribution. Some rams seem to suffer heat stress much more than others,whos e se­ men quality is unchanged (Smith, 1971). It has also been reported that Merino sheep, which are mated with rams chosen on the basis of high or low rectal temperature, show a remarkable difference in fer­ tility found to be lower in the groups of sheep mated with rams with the higest body temperature. As regards goats and particularly the males, Kishore and Rao (1983) observe a decrease in mass motility from 3+ to 0a swel l as a reduced sperm volume between the second and the ninth - tenth week after high temperature treatment. Testicular heating also causes a reduction in the spermatic concentration and in the percentage of live spermatozoa as well as a contemporaneous ab­ normal cell increase. Normal value are recovered between the tenth and thirteenth week.

105 2.Femal e

A number of studies carried out in hot-rooms clearly showed that hightemperatures ,rangin g from 32°t o41°C ,hav ea depressan teffec t onew ereproductio ndu et oa ris eo f1°-2* Ci nbod ytemperature .

2.1.Influenc eo ftemperatur eo noestru s

Oestrusseem st ob eles saffecte db yhig htemperatures ,eve nthoug h delayshav ebee nrecorde da tth ebeginnin go fth ereproductiv eseaso n coinciding with hot periods (Yates, 1953). However,Sawye r (1983) showsa marked influence of temperature of the oestrus behaviouro f Merino sheep.H e observes that the lengtho f the exposure tohig h temperatures andth emomen twhe nthi soccur sar e important indeter ­ mining animal behaviour. If thetreatmen t takesplac e inth etwo - three days prior tó oestrus, only its duration is affected (30-50% reduction). But ifhea texposur e lastssi xday s including theabove - mentioned critical period, the effect can be a total suppression of heat and the lengthening of theoestru scycl e owing tohig hbloo d concentrationso fprogesterone . From thish econclude s that under field conditions, when breeding coincides with hot periods, changes inth eoestru sbehaviou ro fshee pcoul dreduc emating san dnegativel y affect reproduction. Latiefe t al. (1985)repor t that,owin gt ohig h temperatures (35°C), theduration so foestru s increases by 35-46%i n heat-stressedgoats .

2.2.Effect so fhig htemperature so novulatio nan dembryoni csurviva l

Inth eewe ,hig htemperature sar eshow nt oaffec tovulatio nnegati ­ vely.Accordin g toTwaites' sdat a (1967),whic hcontras twit hreport s by Latief et al. (1985), in thegoa t high temperaturesd ono tin ­ fluence ovule fecundation, while the heat stress negatively affects thefollowin gstages ,tha t is,th efirs tstage so fembryoni cdevelop ­ ment. Research on ewes (Alliston and Ulberg, 1961 -Dutt , 1963 - Twaites, 1967- Sawyer ,1979 )show sthat :1 )th ecritica lperio ddu ­ ring which the embryo isparticularl y heat-sensitive is that follo­ wing fecundation (especially the first thre"e days) when it goes through theoviduc t towards theuterus ; 2)th e damage to theembry o dependso nth emomen twhe nhig htemperatur eexposur etake splac emor e thano nit slength ;3 )th enegativ eeffec to fhea tstres sca nb epar ­ tly neutralized by alternating high diurnal temperatures and low nighttemperature sove r2 4hour s (Twaites,1969) . Thiscoul dpla y an important rolei nmitigatin gth enegativ eeffec to fhig hdiurna ltem ­ peratureswhic har e found incertai nbreedin g conditions;4 )th eda ­ maget oth eembry o isclosel y linked toth eincrease dbod ytemperatu -

106 re of ewes, following high temperature exposure. Thereforei itde ­ pendsindirectl yo nothe rfactors ,suc ha sth epresenc eo nfleec ean d theacclimatizatio n capacityo fbreed so r single animals.Unde r tro­ pical climatic conditions,i n the shade,a tdayligh t temperatures ranging from 22° to 33°C, the fertility of the local Pelibuey breed sheepwa s74% ,whil etha to fSuffol kshee pwa sonl y25% .Thi sfindin g was linked toth efac ttha tSuffol k sheep,unlik eth ePelibuey ,wer e heat-stressed, asthei r faster breathing rhythm and higher rectal temperatures showed (Cheminau et al., 1990). Finally, itha sbee n established that,unde r fieldbreedin g conditionsan da thig htempe ­ ratures,shee pwit hth ehighes tbod y temperature have thewors t lam­ bingperformance s (Hopkinse tal. , 1978).

2.3.Influenc eo fhig htemperature so nembryoni cdevelopmen t

Inth eewe ,onc eth eembry oha ssettle dint oth euterus ,i ti sles s affected by high temperatures, so that damage is notably^lessened . However,i fth efemal eundergoe shea ttreatmen t inth esecon dhal fo f pregnancy, a sharp reduction may result in lamb viability at birth and weight, which may be lower than that of anorma l lamb (Yates, 1953 - Shelton, 1964). Changes may occur in the lamb morphology as well: studies by Alexander and Williams (1971)sho w thatth ebod y length,kidne yan dadrena lgland sar econsistentl y large inlamb saf ­ fected by heat-stress while in theuterus ;o n theothe rhand , their musculusbicep s femoris, liver,thyroi d and thymus are smaller.A change inth e relation betweenprimar yan dsecundar y fibresha sbee n detected with negative effects on wool production in lambs (Hopkins etal. , 1980). Anumbe ro f studieshav edeal twit hth ephysiologica l mechanism causing weightreductio n and other effectsobserve d inth e lamb,bu tthei rnatur eremain sunclear .Availabl edat asugges ttha ta decreased blood flow to the uterus, due to high temperatures (Brown and Harrison, 1981), a reduced placental development (Alexander and Williams, 1971)an dchange s inth ehormona l synthesiso f uterinean d placental tissues (Malayer andHansen ,1990 )ar eth emos tcommo nef ­ fects. For the phenomena detected in the lamb to occur, the heat stresseffec t initsel f ismor e importanttha nsever ematerna lunder ­ nutrition during the last gestation stage, according to Hopkins et al. (1980). Tests by these authors have also showed the onset of a marked hyperthermia in lambs born to heat-stressed ewes. Thelambs , beingexpose dt ohig htemperature sdurin gth eday ,showe d sucha fas t breathing rhythm thataccurat econtrol s were impossible. In theeve ­ ning, atlowe rtemperatures ,the y fellasleep ,seemingl y wornou tb y thethermoregulatio n effortsprobabl y resulting ina reductio n inth e thenumbe ro ffeed san dth equantit yo fmil kdrunk .

107 3. From the above, the effects of high temperatures on reproduction in small ruminants and on the farm reproduction level are clear, as indicated by Lindsay et al. (1975) and, more recently, by Kelly (1984) in Australian sheep. It is widely accepted that, under the breeding conditions of temperate areas, environmental temperatures are unlikely to cause heat stress in animals. Therefore, this problem isno t expected to arise. However, goat and sheep breeding is carried on in some European areas as well (Southern and Insular Italy, Gree­ ce, Spain, Portugal), where in spring late and summer it is possible to record temperatures very close to and sometimes higher than the above-mentioned critical threshold. In 1989, for instance, at the Ex­ perimental Station of Bonassai, Sardinia, the maximum temperature ex­ ceeded 32°C, with peaks of 38°-40°C in June (6 days), July (6 days) and August (19 days). Since in Sardinia the reproduction period goes from June to August in adult ewes and from the end of August to;Octo ­ ber in young ewes, the temperature may affect reproduction especially in particularly hot years. The few available data do not enable us to come any final conclusion but strengthen this hypothesis. By means of a ram fertility test, carried out in 1978 with semen from the same rams in different research stations (Sassari, Salonika, Badajoz, Tou­ louse), the influence of a high environmental temperature (32"C) at insemination time (Flamant et al., 1979) was used to explain the low fertility (23%) recorded in a group of Sardinian sheep bred at the Experimental Station of Bonassai. More recently, a field test by Casu et al. (1988) showed that, in flocks where artificial insemination was performed outdoors with exposure to direct sunlight, the fertili­ ty level was lower than in flocks kept in folds or under cover which had been treated by the same operator (43.2% as against 62.7%). With regard to rams, the latest studies by Cappai and Branca (1990, unpu­ blished data) seem to reveal a semen quality degeneration in the Sar­ dinian breed (decrease in mass motility and live spermatozoal rate) as well as a decreased libido in rams bred in sheds lacking air con­ ditioning. Folch (1984) deals with similar data on changes in semen quality in Spain in Ile de France lambs and Romanov rams occurring in summer. These scant data show the need for exhaustive investigation aimed at evaluating and measuring and more efficiently the influence of heat stress on reproduction in small ruminatitsunde r Mediterranean husbandry conditions and at working out the proper technical steps to limit damage. In fact, contrary to the situation in cattle-breeding, we lack guidelines on the proper measures to be taken, apart from using resistant breeds, particularly local ones. As regards sheep and goat, there is still a need to clock the effectiveness of very simple techniques (for instance, the daytime shading of animals and their nightime pasturing). It would be advisable for research to concentra­ te on these requirements inth e near future.

108 REFERENCES

Alexander G., Williams D., 1971.Hea tstres san d development ofth e conceptus indomesti c sheep. Journal of Agricultural Science.76 , 53-72. AllistonC.W. , UlbergG.L.C. , 1961.Earl ypregnanc y loss inshee pa t ambient temperatures of 70° and 90° F. as determined by embryo transfer.Journa lo fAnima lScience .20 ,608-613 . Braden W.H., Mattner P.E., 1970. The effects of scrotal heating in thera mo n semencharacteristics ,fecundit y and embryonicmortali ­ ty.Australia n Journalo fAgricultura lResearch .21 ,509-518 . BrownD.E. ,Harriso n P.C., 1981.Centra l sympathetic controlo fute ­ rine bloodflo wdurin gacut ehea tstress .Journa lo fAnima lScien ­ ce.52 ,1114 . CasuS. ,Sann aA. ,Cappa iP. ,Rud aG .1981 .Problème slié sà l'intro ­ duction etl'utilisatio n debélier sd erac eà viand epou rl ecroi ­ sement industriel en Sardaigne. OptionsMéditerranéennes /3 , 113- 122. Casu S., Cappai B., BrancaA. , 1988.Fecondazion e artificiale emi - glioramento genetico nella pecora da latte.Aspett i tecnico- applicativi. Convegno su:Situazion e eprospettiv e délia feconda­ zioneartificial enell especi eovin ae caprin ai nItalia .Forli . Chemineau P., Malpaux B., Pelletier J., Delgadillo J.A., GuerinY. , ThimonierJ. , 1990.Effetsd el alumièr ee td el atempératur esu rl a reproduction des petits ruminants. Reunion annuelle de l'Associa­ tionpou rl'Etud e del aReproductio nAnimale ,Maison -Alfort . ColasG. , 1980.Variation s saisonnièresd e laqualit éd u spermeche z lebélie r Iled e France. I. Etuded e lamorphologi e cellulairee t del amotilit émassale .Reproduction ,nutritions ,développement .2 0 (6).1789-1799 . Dutt R.H.,Ham m P.T.,1957 .Effec to fexposur e tohig henvironmenta l temperature and shearing on semen production of rams inwinter . Journalo fAnima lScience .16 ,328-334 . Dutt R.H., 1963. Critical period forearl y embryomortalit y inewe s exposedt ohig hambien ttemperature .Journa lo fAnima lScience .22 , 713-719. Flamant J.C., Bib e B., Boyazogl u J., Casu S., Espej oDia zM. ,Vail s Ortiz M.,Zerva sN. ,1979 .Un eexpérienc ed ecroisemen tentr era ­ cesnor d européennese trace s localespou r laproductio n d'agneaux deboucherie , réalisée en coopération par cinq équipesmediteran - éennesd e recherches.Académi ed'Agricultur ed eFrance .Extrai td u Proces-Verbaled el aSeanc e du3 0Mai .1018-1038 . FolchJ. , RochaM. , 1981. Importance de l'activité sexuelle dumai e dansl e développementd ucroisemen t industriele nEspagne .Option s Méditerranéennes.3 ,135-141 .

109 Folch J., 1984. The influence of age, photoperiodism and temperature on semen production of rams. The male in farm animal reproduction. Martinus Nijhoff publishers.141-158 . Hopkins P.S., Knights G.I., Le Feuvre A.S., 1978. Studies of the en­ vironmental physiology of Tropical Merinos. Australian Journal of Agricultural Research. 29,161-171 . Hopkins P.S., Nolan C.J., Pepper P.M., 1980. The effects of heat stress on the development of the foetal lamb. Australian Journal of Agricultural Research. 31,763-771 . Howarth B., 1969. Fertlility in the ram following exposure to eleva­ ted ambient temperature and humidity. Journal of Reproduction and Fertility. 19, 179-183 Kelly R.W., 1984. Fertilisation failure and embryonic wastage. Repro­ duction in sheep.Cambridg e University Press 128-133. Kishore P.N. Rao A.R., 1983. Effect of induced testicular degenera­ tion on semen characteristics of bucks. Indian Veterinary Journal. 60 (4)281-28 6 Latief T.A., Okamoto N. Kanai Y., Shimizuh., 1985. Effects of heat stress on oestrus and ovulation in goats. Procedings of the 3rd AAAP Animal Science Congress.423-425 . Lindsay D.R., 1969. Sexual activity and semen production of rams at high temperatures. Journal ofReproductio n and Fertility. 18,1-8 . Lindsay D.R., Knight T.W., Smith J.F. Oldham CM., 1975. Studies in ovine fertility in agricultural regions of western Australia, ovu­ lations rate, fertility and lambing performances. Australian Jour­ nal of Agricultural Resarch. 26,189-198 . Malayer J.R. Hansen P.J, 1990. Effect of in vitro heat shock upon the syntesis and secretion of prostaglandins and protein by uterine and placental tissues of the sheep.Theriogenology . 34,2 ,231-249 . Moule G.R., Waites G.M.H., 1963. Seminal degeneration in the ram and its relation to the temperature of the scrotum. Journal of Repro­ duction and Fertility. 5,433-446 . Rathore A.K., Yeates N.T.M., 1967.Morphologica l changes in ram sper­ matozoa due to heat stress. Veterinary Research. 81,343-345 . Rathore A.K., 1968. Effects of high temperature on sperm morphology and subsequent fertility inMerin o sheep. Procedings of theAustra ­ lian Society forAnima l Production. 7,270-2^74 . Rathore A.K., 1969. Mid-piece sperm abnormality due to high tempera­ ture exposure of rams. British Veterinary Journal. 125,534-538 . Sawyer G.J., 1979. The influence of radiant heat load on reproduction in the Merino Ewe. I. The effect of timing and duraction of hea­ ting. Australian Journal of Agricultural Research. 30,1133-1141 . Shelton M., 1964.Relatio n of environmental temperature during gesta­ tion to birth weight and mortality of lambs. Journal of Animal Science. 23,360-364 .

110 ShuklaD.D. , BhattacharyaA.P. , 1952a . Seasonalvariatio n in"reac ­ tiontime "an dseme nqualit y ofsheep .India nJourna lo fVeterina ­ ryScience .22 ,109 . ShuklaD.D. , Bhattacharya A.P., 1952b .Seasona lvariatio n in"reac ­ tiontime "an dseme nqualit yo fsheep .India nJourna lo fVeterinar y Science.22 ,179 . Smith J.F., 1971. The effects of temperature on characteristics of semeno f rams.Australia n Journal ofAgricultura lResearch .22 , 481-490. Thwaites C.J., 1967. Embryo mortality in the heat stressed ewe. I. The influenceo fbreed .Journa lo fReproductio n andFertility .14 , 5-14. ThwaitesC.J. , 1969.Embry omortalit y inth ehea tstresse d ewe.II . Applicationo fHot-roo mresult st ofiel dconditions .Journa lo fRe ­ productionan dFertility .19 ,255-262 . WaitesG.M.H. ,Ortavan tR. ,1968 .Effet sprécoce sd iun ebrèv eeleva ­ tion de la temperature testiculaire sur la Spermatogenese du bé­ lier. Annalesd e Biologie animale, Biochimie, Biophisyque.'8 (3) , 323-331. YeatesN.T.M. ,1953 .Th eeffec to fhig hai rtemperatur eo nreproduc ­ tioni nth eewe .Journa lo fAgricultura lScience .43 ,199 .

Ill Italian beef breeds inwar m climates.

H. Lucifero &A . Giorgetti

Dipartimento di Scienze Zootecniche dell'Université. Via delle Cascine, 5- 50144Firenze .

Summary

Italian beef breeds have spread enough in some tropical and subtropical countries; among them the importance of the Chianina breed is particularly emphasized in the present work. The success of the Chianina breed in tropical countries is due to three main reasons: heat tolerance, large growth capacity, good crossing capacity with local breeds. Results collected in Italy both on growth capacity and on bioclimatic characteristics confirm some data collected in tropical countries. In regard to Italian rustic breeds coming from Bos primiaenius. Maremmana breed could have quite good importance in some tropical countries both asbee f breed and aswor k breed.

Résumé

Les races italiennes pour la production de viande sont diffusées dans les endroits chauds; entre ces races nous avons considéré surtout la race Chianina. L'importance de cette race dans les pays tropicaux a été déterminé par trois motifs gui la caractérisent: la tolerance aux hautes temperatures, la grande capacité de croissance et enfin la très bonne capacité de se croiser avec les races locales. La capacité de croissance et les caractéristiques bioclimatiques qui nous avons obtenu dans nos recherches ont confirmé les donnés de recherches conduites dans lespay s tropicaux. Entre les races rustiques qui sont dérivées de Bos primiaenius nous pensons que la race Maremmana a une bonne possibilité d'être utilisée dans les entroits chauds et secs pour la production de viande et même pour letravail .

Introduction

Italian beef breeds belong to different palethnological groups, even if some genetic combinations among them have occurred over the centuries. In a first group we can consider the true beef breeds, which once were dual or triple purpose breeds (Chianina, Marchigiana, Romagnola, Piemontese). They reach somatic maturity quite late, are characterized by medium or large size and show prevailing influences from Bos brachvceros (Chianina, Marchigiana, Piemontese) or Bos primiaenius (Romagnola) and probably from Bos indicus (Chianina and Piemontese). All of them show good or high growth capacity, long and cylindrical trunk, very large amount of muscles. In a second group, typically derived from Bos primiaenius. we can consider the rustic breeds Maremmana and Podolica, hardy and resistent to the environmental (climatic and feeding) adversities but less productive as concerning beef production, in comparison to the first group because of a lower carcass percentage and agreate r amount of bones. Because of their differences both in body conformation and in

112 productivity levels, first group breeds are employed mainly as sired- breeds, for the improvement of meat production in dairy and local breed and second group breeds, nowadays reared only in Italy, are mainly employed as damed-breed, for crossing with more productive genotypes. Germplasm coming from Italian beef breeds has spread enough in many countries with particular regard to some warm climate areas. Among these breeds Chianina and Haremmana cattle have been studied the most; so only these two will be considered in the present work. The first has a great importance in several tropical and subtropical countries, while the second never left its original area except for a brief period during the latethirties .

Chianina breed

Chianina germplasm iswidel y spread abroad. It can be estimated that the number of purebred animals abroad is about 20,000 head, but crossbred animals are probabily over 1 million; of the foreign countries withwar m climates, Brazil hasth e largest population. It has been observed more and more that skin and hair characteristics of this breed are particularly suited for areas with a high sun radiation. Furthermore, even if the large dimension of this breed could in theory be a problem inwar m climates because of the low ratio evaporating surface: body mass, the empirical experience shows a very good acclimatization capacity in tropical countries. Matarazzo recognized three main reasons for the success of the Chianina breed in the tropics: 1. Heat tolerance; 2. Large growth capacity; 3. Good crossing capacity with local breeds. Depending on that Chianina breed in Brazil has particular relevance today. Since the arrival of the first animals in 1956, a great resistance to the unfavourable climatic and health conditions has been observed and similar results have been noted in other latin America countries. Concerning this topic, experimental results with the Chianina breed have confirmed very high environmental resistance and capacity to adapt itself to hot climates, both as purebred and crossbred animals. In Brazil Baccari et al. (1978) found no differences between Chianina and Nellore bullocks in regard to the skin and internal temperature and to rectal-cutaneous and tympanic-cutaneous thermic gradient. Field experiments carried out in Brazil, in severe climatic environment, gave very positive responses (Netto 1976): average rectal temperature (RT) were found to be lower in Chianina than in humped breeds (Guzerat, Nellore, Tabapua); after 1 hr exposure to Sun radiation Chianina and Zebu bullocks gave the same responses and the same resulted in the shade, with air temperature higher than 30°C and relative humidity over 60%. Respiratory rate (RR) was the same in Chianina and Zebu with air temperature higher than 30°C and relative humidity under 60%;wit h the same air temperature and relative humidity over 60% Chianina showed higher RR than Zebu even if RT was the same in the two breeds. These results are in accordance with the report of Bonsma (1978) who pointed the respiratory-type morphology of Chianina breed and the conformation of its head as factors influencing some behaviours such as poor sweating and the increment of RR when exposed to high temperatures. The Author pointed out the similar behaviour of Africander breed, perfectly adapted to tropical environments, and of wild ruminants of tropical areas. A very important aspect for extensively reared cattle in tropical countries is their grazing behaviour. Brazilian Authors

113 observed that at air temperature between 26°C and 31°C and relative humidity between 60% and 80% there were no behaviour differences between purebred or crossbreed Chianina and Guzerat cattle, except that the time daily spent in grazing activities was higher in crossbred Chianina. Other literature also show positive results (Villares et al. 1978a; Villares et al. 1978b) for crossbred Chianina to the Dowling test too (1988). Research carried out at the Department of Animal Science at the Florence University on the responses to climatic conditions of Chianina cows, regarding rectal temperature, skin temperature and respiratory rate showed RT=38,5°C, ST»33,9°C, RR'25,1; RT was related neither to air temperature nor to relative humidity; only ST and RR were positively related to air temperature. Measures were carried out in air temperature range between 4°C and 32°C. It can be concluded that cows responded effectively to the air temperature variations by using mainly RR. The good heat tolerance of Chianina breed, in part common to other Italian white beef breeds, conditions favourable the reproductive efficiency and meat production (Bonadonna 1978; Bonsma 1978; Cesar et al. 1983; Dowling 1988; Enne 1972; Matarazzo 1976; Matarazzo 1978; Matarazzo et al. 1988; Samoggiafi Perill o 1985; Strachan et al. 1980; Villares 1981; Villares 1988; Villares et al. 1978c; Villares et al. 1978d; Villares et al. 1978e; Villares et al. 1978f). Italian beef breeds abroad have always showed good reproductive efficiency; this aspect is very important because the imported animals in tropical countries, besides good growth capacity and high heat tolerance, must profitably combine their genotypes with the ones of local breeds. Often distocyae can be observed when local cows have been inseminated using some European bulls, especially rapid growth breeds. This is due to the large dimension of foetus as compared to the small dimension of cow or small ostetric canal. It does not occur when the Chianina is used as sired breed because of the dolicomorphic conformation even of crossbred calves, with light skeleton and small head in spite of the great dimension of calves, weighing more than 35 kg. Our direct experience in Somalia on Dawara cows, weighing less than 300 kg l.w., confirmed ease of calving when semen of Chianinabull swer e used. Some results concerning beef production, summarized from trials carried out both on purebred and on crossbred bullocks in tropical environments are presented in Tables 1 and 2. The positive influence of Italian germplasm on local humped breeds can be observed; by using crossbreeding one can obtein quite precocious Fl in comparison to local purebreed animals and a greater amount of low fat meat which is a good response to the increasing consumer demand for beef products low in fat; moreover purebred Chianina also show very good performance, comparable to the ones obtainable inEurope . The very sactisfactory adaptation to tropical environments of Chianina breed is also probably due to Çhe good resistance to parasitic diseases, which, in the opinion of many breeders, is caused by the good skin mobility preventing insect attacks.Als o one must not forget the high aptitude to graze in bushy areas where other breeds, shorter than Chianina, can suffer from lesions to the udder or to the scrotum, entrance doors forpathogeni c microbes orworms .

Maremmana breed

Maremmana breed is a rustic breed derived from Bos primigenius populations, arrived in Italy with the Huns in 452 a.D. or from Crete

114 Table 1.Growt h characteristics of different genotype young bulls inBrazil .Result s of sometrial s in different rearing conditions.

Genetic Average Author type daily gain (9)

Nelore 1254 Enne, 1972 Guzerat 1153 5/8 CH 3/8 ZB 1322 5/8 SH 3/8 ZB 1220 5/8 CN 3/8 ZB 1520 Chianina 1467 Guzerat 1021 7/8 CN 1/8 NE 1409 CN x NE 602 Bonadonna, 1978 MR x NE 655 N It Guzerat 609 3/4 CN 1/4 GZ 918 Hatarazzo, 1976 1/2 CN 1/4 CH 1/4 NE 973 Chianina 1046 Zebu 847 Villares, 1981 CN x ZB 1158

CH: Charolaise; CN: Chianina; GZ:Guzerat ; MR: Harchigiana; NE: Nellore; SH: Shorthorn; ZB: Zebu, not specified breed.

Table 2. Beef production improvement by introduction of Chianina germplasm in Zebu breeds.

Genetic Item Improvement Author tupe %

CN x ZB Birthweight 16.7 Hatarazzo, 1978 n Weaningweight 29.4 n if n A.D.G. 40.0 n it H Age at slaught er 45.0 n it " Killing out % 11.1 ft if 1/4CN 3/4NE A.D.G. 40.7 Villares, 1978 b CN x NE M 37.0 n it 3/4CN 1/4NE M 40.7 n n 1/4CN 3/4NE fi 14.8 Villares, 1978 c CN x NE n 14.8 tt n 3/4CN 1/4NE N 25.4 n n

115 about the second century b.c., utilized in the past for the triple purposes work, milk and beef production. It is characterized by a slowness of the sexual development in spite of a relative early maturity of carcass composition. More and more the importance of this breed in Italy for the extensive production of calves has been pointed out. This is especially profitable for the exploitation of Mediterranean maquis which gives both food and refuge from climatic adversities. The excellent rusticity and frugality of Maremmana breed aswel l as the maternal aptitude of the cow and the perfect adaptation to the Maremma environment are well known; on the contrary very little information is available on its capacity to adapt itself to hot climates. Maremmana cattle were transferred in Cyrenaica (Libya) from 1933 thanks to Libyan Colonization Corporation operated by Italian Government. This Corporation endowed all of its farms with at least two cows mainly used for work in the fields. The importation was successful so that in 1938 in Cyrenaica there were about 1800 head. As Bettini and Salerno (1954) pointed out Maremmana cattle responded well to the expectations: adult animals, even if consigned to inexperienced staff, were able to satisfy all work requirements, even in impervious and hard areas. Unfortunately all of them were lost during and after the second world war so that today it.i s not possible to control scientifically their performance in such countries. In regard to bioclimatic parameters collected on cows reared in Maremma (Tuscany) no interrelationships were found between RT and RR on one side and air temperature (AT) and relative humidity (RH) on the other side (range: AT:11°C-27°C RH: 40-87%); from this one can reasonably expect a good thermotolerancean d good adaptation capacity in subtropical areas. Giuliani was the first Author who took interest scientifically about Maremmana breed, to whom we owe the setting up of selection activities and recognition of the breed's importance. In more recent years some Authors (Giorgetti et al. 1986; Iannella et al. 1977; Lucifero et al. 1977; Lucifero et al. 1978; Lucifero et al. 1981; Lucifero et al. 1987; Secchiari et al. 1979) have pointed out the good reproductive characteristics which are remarkable when we consider the feeding and climatic constraints which this breed must overcome in its proper breeding environment. In particular a quite good fertility, a very low incidence of abortions and newborn mortality, and in consequence a very high percentage of weaned calves, was observed. A very important element, emphasized by the Authors, is that the good reproductive characteristics remain almost unmodified in outbreeding with specialized beef breeds (Charolaise e Chianina) wich is a common method for the quantitative and qualitative improvement of meat production. Our trials (Lucifero et al. 1978; Lucifero et al. 1981) carried out on hematic characteristics of the cows over the year pointed some critical periods during the winter and the summer caused by the pasture decline. In these periods we observed very low hematic phosphorus and glucose contents (Lucifero et al. 1978;Lucifer o et al. 1981) which negatively effect fertility. Infact it has been observed that cows with significantly low values of hematic phosphorus during the mating season did not become pregnant (Lucifero & Giorgetti 1987). These results put in evidence feeding deficiencies, mineral and energetic, analogous to that occurs in cows of some tropical and subtropical semiarid areas where the seasonality of forage production or the growth of only ephemerales herbs are the most important obstacles to animal husbandry. In some cases, as in Maremma, the

116 feeding Improvement by mineral integration, a proper rotation of pasture or the artificial improvement of the pastures by manuring or seeding may be advisable.

Conclusions

By the examination of specialized literature and the results of some trials carried out at the Department of Animal Science of the Florence University it ispossibl e to form some conclusions. Chianina breed, and Marchigiana too, have a considerable importance for improvement beef production in some developping countries as purebred as well as crossbred, both with local rustic breeds and with very precocious specialized beef breeds. Besides Chianina and Marchigiana the world is showing an increasing interest in the Piemontese breed, due to the lean characteristics of meat and the very low fat content of the carcass. Concerning the Piemontese one can remember the large programm aimed at the beef improvement of less productive breeds, by embryo-transfer in the south of Italy. If the program will have success it will be utilized as a model to replicate inothe r disadvantaged areas of the world. In regard to the Maremmana breed, interventions aimed at the rationalization of feeding and rearing management demonstrated the possibility of production improvement in its original environment. Its past introduction in Libya and its resistence and frugality characteristics showed in its proper environment, which has a lot of common climatic aspects with some mediterranean and subtropical environments, can recommend its spread in those areas. Concernig the Maremmana and Podolica their employment both as beef breeds and as work breeds could be advisable, because the increasing interest for animal power in some developping countries.

References

Baccari JR. F., Ramos A.A., Villares J.B. & Curi P.R., 1978. Temperature interne e esterne di bovini Chianini e Zebuini Heiore. Atti 2° Congresso Internazionale sulla Razza Chianina, Sao Paulo, 156-162. Bettini T.M. & Salerno A., 1954. Relazione presentata dalla Delegazione Italiana al Congresso Internazionale del Cairo per la discussione del problemi relativi all'allevamento del bestiame nelle regioni tropicali e subtropical!. F.A.O. Roma. Bonadonna T., 1978. Caratteristiche economiche della razza Chianina. Atti 2° Congresso Internazionale Razza Chianina, Sao Paulo, 111-121. Bonsma J.C., 1978. L'importanza del bestiami europei nei tropic! per il rendimento nella produzione della carne. Atti 2° Congresso Internazionale Razza Chianina, Sao Paulo, 52-70. Cesar S.M., Boin C. & Barbosa C, 1983. Effect of type of animal feeding level on the performance of bulls in feedlots. Animal Breeding Abstract 51:427 abstract only. Dowling D.F., 1956.A n experimental study of heat tolerance of cattle. Australian Journal of Agricultural Research 7:469-481. Dowling F., 1988. La Chianina nell'impiego razionale del patrimonies bovino inAustralia . Chianina Quarterly 2:(4), 10 abstract only. Enne 6., 1972. Prime osservazioni sulla prove di incrocio delle razze bovine da came italiane con razze dell'America Latina. Rivista di Agricoltura Subtropicale e Tropicale 66:3-21.

117 Giorgetti A., Lucifero M., Zappa A. & Lupi P., 1986. II profilo motabolico negli animal!d i interesse agricolo. 3.Valor i ematici di riferimento nella razza bovina Maremmana. Zootecnica e Nutrizione Animale 12:153-158. Giorgetti A., HartiniA. , Lupi P. & Lucifero M., 1990.Osservazion i su parametri bioclimatici, quadro ematico e caratteristiche riproduttive della razza bovina Maremmana. Taurus. Inpress . Giuliani R., 1937. La selezione genetica morfofunzionale della razza bovina Maremmana. Rivista di Zootecnia 14:(5). Iannella G.G., Lucifero M., Secchiari P., 1977. I parametri riproduttivi della razza bovina Maremmana. Zootecnica e Nutrizione Animale 3:193-208. Lavezzo W., Villares J.B., Gonçalez D.A. & Padovan! CR., 1978. Abituali etologiche di gemelli 1/2 Chianino-Guzerà e Guzerà nel sistema di pascolo. Atti 2° Congresso Internazionale Razza Chianina, Sao Paulo, 174-175. Lopes L.S., 1978. Nostra esperienza con la razza Chianina. Atti 2° Congresso Internazionale Razza Chianina, Sao Paulo, 448-456. Lucifero M., Iannella G.G. & Secchiari P., 1977. Origini, miglioramento e prospettive della razza bovina Maremmana. Edagricole, Bologna. Lucifero M., Secchiari P., Ferruzzi G. & Buonaccorsi A., 1978.Riliev i ematici di alcune costanti vitaminico-minerali in bovini allevati allo stato brado. Zootecnica eNutrizion e Animale 4:369-375. Lucifero M., Giorgetti A., Lupi P. & Marchese B., 1981. Contenuto ematico di calcio, fosforo, vitamina A e caroteni in bovine maremmane allevate allo stato brado. Zootecnica e Nutrizione Animale 7:119-129. Lucifero M. & Giorgetti A., 1987. Il profilo metabolico per il miglioramento delle condizioni alimentär!I n allevamenti estensivi e semiestensivi. Atti XXII Simposio Internazionale dl Zootecnica, Milano, 79-98. Matarazzo G., 1976. Una nuova razza cosmopolita?. Atti 1° Congresso Internazionale Razza Chianina, Firenze, 67-75. Matarazzo G., 1978. La contribuzione della razza Chianina per la produzione di carne in Brasile. Atti 2° Congresso Internazionale Razza Chianina, Sao Paulo, 132-155. Matarazzo G., Netto A.F., De Assis G.P. & Nunes P.L.A., 1988. Produzione di carne alla macellazione di meticci Chianini x Nelore. Chianina Qaurterly 2:(4), 18 abstract only. Netto A.F., 1976. La razza Chianina in Brasile. Atti 1° Congresso Internazionale Razza Chianina, Firenze, 52-66. Samoggia G. & Perillo G., 1985. Marchigiana. Evoluzione e diffusione della razza nelmondo . Italia Agricola. Secchiari P., Lucifero M. & Iannella G.G., 1979. Indagine sulla efficienza risproduttiva della razza bovina'Maremmana . Zootecnica e Nutrizione Animale 5:437-448. Strachan R.T., Peart W.J., Coleman R.G., O'Rourke P.K., 1980. Post- weaning growth and carcass characteristics of Chianina, Brahman and Hereford cross and Hereford steers in southern Queensland. Australian Journal Experimental Agriculture and Animal Husbandry 20:257-284. Villares J.B., 1981. Performance of Chianina bovines in the Brasilian tropics. Atti 3° Congresso Internazionale Razza Chianina, Calgary, 23-27.

118 Villares J.B., 1988. Prova di accrescimento di Chianini e Chianini x Zebu nel Brasile tropicale.Chianin a Quarterly 2:(4), 18. Villares J. B., Gonçalez D.A., Lavezzo W. & Rocha6.P. , 1978a. Test di tolleranza al calore di 3/4 Chianina-Zebü e di zebuini Nelore. Atti 2°Congress o InternazionaleRazz a Chianina, Sao Paulo, 163-167. Villares J.B.,Lavezzo W., Rocha 6.P., Gonçalez D.A. & Baccari Jr.F., 1978b. Reazioni di prodotti di incrocio semplice e triplo di Chianina alla tensione termica. Atti 2° Congresso Internazionale Razza Chianina, Sao Paulo, 168-173. Villares J.B., Silveira A.C., Rocha 6.P. & Lavezzo W., 1978c. Indice di conversions di alimenti nei bovini Chianini, zebuini Nelore e loro incroci. Atti 2° Congresso Internazionale Razza Chianina, Sao Paulo, 269-283 . Villares J.B., Ramos A. de A., Rocha 6.P. & Silveira A.C., 1978d. Prova di guadagno di peso con lo scopo di selezione di bovini Chianini, zebuini Nelore e meticci.Att i 2° Congresso Internazionale Razza Chianina, Sao Paulo, 319-333. Villares J.B., Domingues C.A.C., Rocha 6.P. S Ramos A. de A., 1978e. Confronto fra incrocio semplice e triplo per guadagno di peso. Atti 2°Congress o Internazionale Razza Chianina, Sao Paulo, 344-352. Villares J.B., Pardi H.C., Lavezzo W. & Rocha G.P., 1978f. Controllo di carne e taglio di carcassa nei meticci Chianina a incroci semplici e tripli. Atti 2° Congresso Internazionale Razza Chianina, Sao Paulo, 400-412.

119 BREEDING STRATEGIESI NDRY-HO T COUNTRIES

DarioCIANC I Dipartimentod iScienz eAnatomiche ,Fisiologich ee dell eProduzion iAnimal i Universitéd iPis a- Vial edell ePiagge ,2 - 5610 0PIS A- ITALI A

Summary Animalbreedin g systemsi n tropical andsubtropica l areas arenoumerou s sotha t they canadap tt odifferen t naturalan dsocia leconomi cenvironments . Pastoral and nomadic systems most frequent in Africa and South America are completely replaced inman y asiatic areas bylittl e herdsi nrusti c condition ori n family urban (born near urbane settlement, expecially those characterized by rapid and recent growth) show different problems in respect of intensive breeding or intensive and industrialone . Each of these systems must be emphasized in relation to their real environments, technology and natural availability in order to obtain in each area quantitative and qualitativeincreas eo f zoothecnicalproductions .I n thesearea soperativ eprogram smus t considèrean dimprov e natural and socialeconomi cresources ,withou tcompet ewit h the traditionalproductiv e system. Livestockbreedin gan dit srelativ efeedin g techniquesfollo w contrastingphilosophies , and often have differing significance in different countries in relation to climatic conditions,dietar yhabit san dth epopulation' s socialcustoms . In hot dry climates the relatively high density of the animal population is in stark contrast toit s low productivity; any strategy for promoting development there must be accurately evaluated in order to avoid inducing a fear of poor results which could discouragefurthe r investment. Agrowin gdisaffectio n with animalhusbandr y couldthu s result and exacerbate the technological gap already existing in these countries; in particular thegapin ghiatu sbetwee n techniques generally availablethroughou t theworl d andth esocio-economi crealit y ofindividua lnations . Heterogeneity in environmental, technical and social conditions has created an extremely complex situation in which many variables must be considered, such as the breath andvariabilit y of thenatura lresource s which the animalpopulatio n andit s food sourcerepresent , aswel l asth erelationship s between manan d animal,environmen t and technology. Nonetheless, livestock breeding in all hot dry countries poses a certain number of commonproblem swhic hca nb esummarize di nth efollowing : 1. the various genetic varieties raised (species, breeds and ecospecies), although possessing a great adaptive capacity, are quite unproductive in comparison to their temperate-climatecounterparts . 2. physically, the environment (above all,it s temperature) produces a greater need for thermolysis and related difficulties to which high-yield species.are particularly susceptible. 3. nourishment is often inadequate due to both the erratic supply and poor quality of tropical feeds. 4.poo r hygienerender sth eenvironmen tfertil e terrainfo r thedevelopmen t of pathogens andthei rvectors . 5.a nacut eneed sexist sfo r adequateeconomi can dtechnologica l infrastructures, aswel l asfo rqualifie d personnel. 6. except in rare instances, there is a lack of the technical means of and appropriate scientific researchi n animalhusbandry . In arid countries today efforts to raise production yields to the levels found in developed countrieshav ebee nhindere d byth eman y limits set by the unavailability of

120 capital investment, technology and quality labour, and especially by the breeders' attachment to their traditional methods of raising' livestock. These limitations are particularly dramatic in the field of animal husbandry in view of its low efficiency (second, at times even third, trophic level) and the low quantities of food destined for humanconsumptio n which thelan di sabl et oyield . Inman y emergingnation ssignifican t changes areeviden t which havebrough t about, notonl y aquantitativ eimprovemen to flivestock ,bu tsignifican t progressi n itsqualit ya s well;albei t theprogram s and studiescomplete d upt ono whav ebee n conducted largely inth emos tfavourabl e areas. Onemus t notloos e sighto f thelarg evariet y of management systems andmanner si n which tropicallan di spu tt ouse ; theyrang efro m thetraditiona l nomadic, sedentary and pastoral systems, to family, agro-pastoral and, increasingly, tointensiv emethods , such asfar m andlarge-scal ebreeding . Generally speaking, in arid areas (largely corresponding to developing nations) the strategy followed in animal breeding programs must be formulated with several fundamental objectives inmind .The y should beabl eto : 1.inser t themselves intoth e socialfabri c of thecountry ,involvin g aswid e aportio n as possible of thepopulatio n currently engaged in raising livestock by improving their traditionalmethods ,a swel l asintroducin gthe mt oalternativ eones ; 2. utilize the country's available resources to their fullest, not only the genetic and environmental ones,bu tth ehuma n and technological onesa swell ,an davoi d asmuc h aspossibl eresortin g toburdensom e importswhich ,i nan yevent ,d ono talway sprov e productive; 3. avoidnegativ eeffect s ontraditiona lproductio n methods whichcoul d besubjecte d to unbearablecompetitio n inth emarket sfo r theirgoods ,bu tinstea dt o 4.promot epositiv e integration of and theconsequen t benefits upon local products and theirvalue . One aspect which must be granted the utmost consideration in developing breeding strategies for these areas is the repercussions their implementation might have on traditionalmethod scurrentl yi nuse . Theultimat eobjectiv e of anyprogra m shouldb eth e introduction of new, more or less intensive systems for raising livestock which could harmonise with and thereby increase the value of traditional systems. All too often, closed-cycle (?) projects carried out with imported breeds are quite demanding economically, technologically and socially (qualified labour),demand s which recipient nations are unable to meet (they therefore often require aid from international organizations). Above all, however, these animals are introduced into local economies where they reside like foreign bodies causing detrimental competition and its negative repercussions ontraditiona lproducts . Objectively, it shouldb eadmitte d thateve n slightimprovement si n theproductivit yo f indigenous breeds would require a long time, especially when considering large-scale breeding- trai tinheritanc ei sextremel ylo wunde rth edominan tenvironmenta lcondition s andth egenotype s aregenerall y inequilibriu m with theirlivin g environment. Whenon e then adds the time necessary for breeders to make a genetic assessment, one can easily understand the generally low efficiency and consequently rare recourse to programs aimeda timprovin gautochthoni canima lpopulations . Large-scale breedingha stherefor e been themos tfrequen t object of attention becausei t seems the most amenable to genetic enhancement and the introduction of advanced technology. Nevertheless,despit ea boo mi nproject s ofthi ssor t inman y countries,largel y funded by international organizations, theresultin g systems, either large-scale orfarming , still produce anextremel y modestproportio n of thetota l livestock in therelativ e nations (less than 5%), and thusrepresen t aminima l steptoward sresolvin g theirmai n economic and nutritionalproblems . Thelimit s tointegratin g new systemsint oth eproductiv e network of many countries are set, not only by technological problems, but by the presence of pathogenic agents (trypanosoma) in agricultural areas devoted to large-scale breeding and by the greater efficiency of thesearea si nproducin gfoo d directlyfo r human consumption.

121 Percentage-wise, morelan di stherefor e given over topastora l systems which, asha s traditionally beenth ecase ,stil lrepresen tth emos twidesprea d forms oflivestoc kraising , practised todat eo nmor etha n 95% of thelan d area; afigure which ,despit eth esystems ' many limitations, shows no sign of decreasing. The current system suffers from a numbero f worrisomeproblems : - inadequate forages, despite migration to different pastures according to seasonal changesi n rainfall. - slowreproductiv e rhythmswhic h limitdemographi c growth andtherefor e the number ofmarketabl ehead . - lowprofitabilit y duet odifficult y inplacin g goodso n theconsume rmarkets ,normall y quitedistan t from production areas andfurthermor e poorly serviced by transportation networks. - thelac ko fth einfrastructur e necessary for theconcentratio n andpreparatio n ofproduc e for the marketplace (milk refrigeration centres, collection and fattening plants for animalsdestine dfo r slaughter). This system has long been under discussion since today these peoples are now attemptingt ochang et oa mor esedentar y wayo flife . Sincean yassistanc emus tb eaime d at helping them develop non-migratory methods, there is naturally an urgent need for researcho nthei reconomi cactivit y andalternativ eproductio n systems. National governments andinternationa l organizations arefacin g enormous difficulties ininstitutin gprogram sdesigne dt oimprov ebreedin gproductivit y andth egenera lqualit y of life of the herders because the environments currently or potentially involved are resistant to radical change. Investment in these areas is moreover limited by unsatisfactory costeffectivenes s -ver yhig hexpenditure scanno tb eexpecte dt oproduc e moretha n modest gains. The situation in several countries requires consideration of the social benefits of avoiding excessive urbanization without a concomitant increasei n thepossibilitie s for alternativeemploymen t -a situatio n whichcreate sother ,a ttime smor eseriou sproblems . Moreover, the depopulation of pastureland cannot always be considered a benevolent return from the wild, since often the removal of domestic animals has caused severe imbalances in anatura l biological system traditionally accustomed tointegratio n often maintainedwithi nth elimit so freciproca l compatibility. A concrete working proposal for large-scale breeding systems must necessarily provide for: - study of indigenous livestock in order to determine production limits and the most suitablebreedin gtechniques . - assessingpasturelan d productivity andvegetativ ecycle si n order to estimate potential seasonal yields; determine the periods in which the need for feed supplements is greatest and define the animal genotypes which can be best reared under each condition. - the localization of all other usable food resources, as well as those zones with the greatest soil humidity (perhaps by means of aerial infrared photogrammetry)fo r the cultivation offorag efor emergenc y stock-piles. -th ecreatio n of specialized breedingcentre sfo rintegratin gnomadi cactivity ,particularl y through fattening calves and lambfo r slaughter and managing cows during milking periods. From personal experience wehav e found that indigenous breeds are highly amenablet oprogramme d feeding ofeve nmodes tnutritiv eM Evalues . - specific attention to social aspects linked to the aims as well as the traditions of the peopleinvolve di nthi sproductiv e system. A development which I believe must be encouraged through suitable technical and technological assistancei sth etendenc y towardfamil y farm breeding,a typica l systemi n manypart so fAsia .I ti sparticularl y interestingbecause ,althoug himprovemen t costsar e quite high,i tca n beexpecte d toproduc e significant economic and social benefits, while at the same time remaining faithful to the fundamental objectives of breeding enhancementprograms . Among thedifficultie s involved in transforming pastoral breeding to an agro-family form, thereclamatio n ofarea s nearby the farmlands, currendy unusabledu e to poor

122 sanitation (Glossina and Trypanosoma), could prove to be the decisive factor in consenting theevolutio n towardthi smor eefficien t system.Suc ha syste mpermit s better integration betweenagricultur ean danima lbreedin gan dcoul drepresen ta steppin gston e toward sedentary systems. An independent route, not always welcome, has been the transformation of herding intourba n family-farm raising.I nman y countriesthi s sorto fbreeding ,appearin gi nth e cities due to their overly rapid expansion, has assumed an irreplaceable role in the economy andculture .Ofte n itprovide s aconsiderabl e proportion of thecity' s supplyo f animal produce, aproportio n which even large-scale methods would have difficulty in attaining. Many townships, faced with the inadmissibility, at least in theory, of urban farm raising, due to obvious sanitary, environmental and production problems, havetrie d to eradicatei tthroug h variousincentive sprogram s andeve ncoercion ,despit eth efac t that i therear en oworkabl ealternatives . I A few years ago, describing the situation in the city of Mogadishu, I wrote, "Concerning small animalfarm si nth ecity ,th esignifican t economican d social functions j which theycarr you traise s seriousdoubt s ast othei r beingreplaced , atleas t inth e short I term.Therefore , amor edetaile dexa mi si norder. -on ewhic hi sno tlimite d toregardin g j itsnegativ e aspects,bu twhic h attemptst odetermin e whati slackin g andprovid ea bette r basis on which to make the choices necessary to insure more appropriate production, above all by promoting the adoption of the more productive cross-breeds, providing efficient hygiene and sanitary assistance and creating forage producing fields at a convenient distance". Today my convictions still lie in this direction, in the advantages of favouring the activities of small breeding enterprises (of course, better stilli f they are family farms) over those of largeplant s which proportionally involve amuc h smaller segmento f the population. In conclusion, the generally poor yield which can be obtained from most of the territory under consideration, nomatte rho wimprove d or supplemented, doesno t leave open any hypothesis of its rapidly up-scaling production facilities. Further limits are imposed byclimati c conditions,a swel l aspreferentia l utilization of themos t productive land for direct cultivation of human foods. Although fully acknowledging the demonstrated necessity of this, and also being unable to offer a thorough economic comparison between agriculture andanima l raising in thesechoic e territories,I believe that solutions are called for which integrate the current pastures with high-yield land. This,particularl y in order to satisfy the legitimate aspirations of thenoma d population, bound to increase in time, to engage in activities which are both moreprofitabl e and, which aboveal lallo wgreate racces st osocia l comforts. Thecurren t gapbetwee n available technology andtha twhic h isinstea d actually inus e represents amajo r obstacle towards fully realizing the potential of tropical areas.Thi s gap, of course, varies according to both time and place. However, the rare but real successes in supplying appropriate technology to developing countries give cause for optimism. j In these areas "appropriate" means techniques which respect the nature of the land devoted toraisin g animal and the social aimso f thepeopl e engagedi n it. Research in improving livestock yieldsmus t therefore seek to adapto rmodif y thesystem s currently in userathe r than implement grandprojects , all tooprevalen t nowadays,i n whichhig h j technology isintroduce d in developing countries atgrea tcos t and often with littlehop e | of success. Bibliografv Abdul Wahab Qureshi, 1987 - Current trends and possibilities of increasing small ruminantproductio n inth eNea rEast . In:Smal lRuminant s in theNea rEast ,Vol .I , FAO, An. Prod.Health,pap . 54,Roma . Acharya R.M., 1982 - Sheep and goat breeds of India.FAO, An.Prod. Health, pap. 30, Roma. 123 Blaxter K.L., 1967 - The energy metabolism of ruminants.Hutchinson Sei. e Tech., Londra. Celi R., Cianci D., Zezza L., Jirillo E. (1981) -Electrophoretic mobility of zebu red cells.Worl dRevie wo f AnimalProduction , 3,11-13. Celi R., Cianci D., Sinatra M.C., Nuh H.S. (1987) - I residui agroindustriali degli agrumi - Ipotesi di utilizzazione nell'alimentazione del bestiame in Somalia. Seminariod i studisugl iagrumi ,Mogadiscio ,ottobr e 1987. Cianci D. (1977) -L aproduzion e animalene i climicaldo-aridi :interazion e genotipo- ambiente.Fac . Agraria, Univ.Naz .Somala . Cianci D. (1978) -1 fabbisogni alimentari degli animali domestici e la produzione foraggera nelle aree caldo-aride. Studie Ricerche délia Facoltà diAgraria , Univer. Naz. Somala, 186-194. Cianci D.,Cel i R., Zezza L.,Abdihaki m M.A., Abdiyusuf F.,Abdiwal i O.Y. (1980) - L'utilizzazione dei sottoprodotn'dell acoltivazion ede lbanan onell'alimentazion e dei bovini dalatte .I °Boll .Sei .Fac .Zoot .e Veter. Univ.Naz .Somala , 113-124. Cianci D. et al. (1980a) - Piano di sviluppo zootecnico della Somalia. Rapporto preliminare.Minister odell apianificazione . Rep.Dem .Somala . Cianci D., Scaramella D. (1980a) - Animal production and wild life in the Somali Democratic Republic. Relazione svolta al 1° International Congress of..Somali Studies,Mogadisci o luglio 1980. Cianci D.,Hash i A.M.(1981) -A strategy for the genetic improvement of livestck in Somalia.11 ° BollettinoScientific o Fac. Zootecniae Veterinaria ,Univ .Naz .Somala . Cianci D., Zezza L., Orlandi M., Abdulquadir Ismail, Hashi A.M., Mohamed Sheik Mohamud (1983) -Un astrategi ape ri lmigliorament ogenetic ode ibovin id alatt ei n Somalia. IVe Bollettino Scientifico Fac. di Zootecnia e Veterinaria, Univ. Naz. Somala. Cianci D., Zezza L., Mohamud (1984) - Early weaning of zebu calves in Somalia. World Anim. Prod., XX, 2, 39-43. Cianci D., Zezza L., Orlandi M., Cataldo P., Abdulquadir Ismail, Hashi A.M., Skekmussa M. (1985a) - Trials on confined feeding of zebu calves from nomadic herds.Worl d Review of Animal Production,XXI , 2,41-45. Cianci D., Hashi A.M. (1985) - A strategy for animal production improvement in African countries.Worl d Reviewo f AnimalProduction ,XXI , 2,77-79. Cianci D., Sartore G. et al., 1989 - Investigations on small ruminants reared in Somalia: body weight andbod y measurementsi n Somaliblackhea d sheep (Incors o distampa) . Cianci D., Hashi A.M., Cataldo P., Liponi G.B. (1989a) - alkaline predigestive treatment of agricultural byproducts in Somalia. Produzione Animale, (In corso di stampa). Cianci D. (1989) - Allevamento ovi-caprino nei Paesi emergenti,particolarment e in Africa. XXIV Simp.Int .Zoot. , Milano2 0april e 1989. Coppock D.L., J.E. Ellis, J. Wenphal, J.D. Mccabe, D.M. Swift, K.A. Galvin, 1982 - A review of livestock studies of the South Turkana ecosystem. Proc. SR-CRSP Workshop Kenia.Winroc k Int.,Morrilton , Arkansas. Creek M.J., Redfern D.M., Squire H.A. (1974) - Intensive cattle feeding in Kenya using levels of molasses. World Rev. of Anim.Producr , X, 4,58-68 . Demiruren A.S., 1987 - Sheep production potential in the eastern Mediterranean. In: Small ruminants in theNea rEast ,Vol .II ,FAO ,pap .55 . Devendra C, 1979- Ruminan tnutritio n andproductivit y inth eAsea nregion , Seminar on animal health and nutr. in the trop., Townsville, James Cook Univ., Australia, 38 pp. Economides S., 1983- Intensiv e sheepproductio n inth eNea r East. FAO, An.Prod . Health,pap .40 . EsmallL S.H.M., 1986 -Acclimatizatio n of imported Saanen Goats in North Yemen. W. Rev. Anim. Prod., XXII, Jan.-Mar., 79-88. Fall A., M. Diop, J. Sandford, Y.I. Wissocq, J.W. Durkin e I.C.M. Trail, 1982 - Evaluation ofdi eproductivitie s ofDjallonk e sheepan dNidam acattl ea tth eCentr ed e

124 recherches zootechniques,Kolda ,Senegal .BLC ARes .Rep .N °3 . Gall C, 1987- Mil kproductio nfrom shee p and goats.In :Smal lruminant si n theNea r East, Vol. II, FAO,pap .55 . Hashi A.M., Cianci D. (1985) - Chemical composition of some range forage in Somalia. VF Boll.Scient .Fac .Zootec .e Veter .Univ .Naz . Somala, 109-116. ILCA (International Livestock Centrefo r Africa) (1983) -ILC AAnnua lReport .Addi s Ababa,Ethiopia . Le Houe'Rou H.N. (1980) - Chemical composition and nutritive value of browse in TropicalWes tAfrica . In:éd .L eHoue'ro u -Brows e inAfrica , ILCA,Addi s Ababa, pp 261-289. Mack S., 1982 - Disease as a constraint to productivity. In: Small ruminant breed productivity inAfrica , Ed.R.M.Gatenb y eI.C.M .Trail ,ILCA . Mosi A.F.,Shankut e Tesema andTempl e R.S. (1976) -Livestoc k nutrition in thedr y tropics of Africa. Proceedings, First International Symposium Feed Composition, Animal Nutrient Requirements and Computerization of Diets. July 11-16, 1976, Utha StateUniversit ,Logan , Utha,USA . NorrisJ.J . (1975) -Rangeland s andthei rimportance .FAO/U NSOM , 72/003. Otchere E.O., 1986 - Small ruminants production in Tropical Africa, FAO Doc. 86/61887, 8pp . Peacock C.P., 1983- Phas eesploratoir e d'uneetud ede s systemsd eproducti o animale dans le Gourma malien: données de base sur le cheptel caprin et ovin. Dpc.progr . AZ92c ,Centr eInt .Elevag ee nAfrique ,Mali . Preston T.R., Willis M.B. (1974) -Intensiv e beef production. Pergamon Press. ScaramellaD. ,Cianc iD. ,Macchion iG .(1989 )- I lcammello . EdagricoleBologn a(I n corsod istampa) . Shkolinkl A., A. Borat e I. Chosniar, 1972 - Water economy in the bedouin goat. Symp. Zool. Soc. Londra, XXI, 229-242. SilanikoveN. , 1986- Fee d utilisation, energy and nitrogen balance in thedeser t black bedouin goat. W. Rev. Anim. Prod., XXI, Apr.-Jun., 93-96. Valenza J., Calved EL, Orve J. (1971) - Engraissemente intensif de Zebu Beulh senegaleis (Gobra).Rev . Elev. Med. Vet. Pays Trop.,24 ,79-109 . Wilson R.T., 1981 - Livestock production. In: Systems research in the arid zones of Mali:initialresults .ILC ASystem sStud yn °5 . Wilson R.T.e J.W . Durkin, 1983- Livestoc kproductio n incentra l Mali:weigh t at first conception and ages atfirs t and second parturitions in traditionally managed goats and sheep.J . Agric. Sei. Camb., C, 625-628. Wilson R.T., 1987- Th eintegratio n of goatsi nth elivestoc k sistemso f arid and semi- arid Africa. Proc.I VInt .Conf .o nGoat , Vol.II ,Brasilia . Zezza L., Cianci D., Hashi A.M. (1981) - Prima indagine morfologica sui bovini somali attraverso il rilievo fotografico. II0 Bollettino Scientifico Fac. Zootecnia e Veterinaria, Univ.Naz .Somala . ZezzaL. ,Cianc iD. ,Vonghi a G.,Marsic oG . (1985) -L aqualit àdell ecarn idegl izeb u dellaSomalia .VI 0 Boll.Scient .Fac .Zootec .e Veter .Univ .Naz . Somala, 103-108. Zoroug M.G., 1987 - Research and development priorities to increase forage supply from range and available lands in the Near East. In: Small ruminants in the Near East, Vol. I, FAO,An . Prod. Health, pap. 54, Roma.

125 Strategies for the use of agricultural by-products as ruminant feed in warm climates F. Polidori & G. Savoini Istituto di Alimentazione Animale, Université degli Studi di Milano, via Celoria 10, 23100 Milano.

Summary The use of agricultural by-products for livestock feeding reduces both feeding costs and environmental pollution. In warm climates there are large quantities of fibrous by-products; these require physical and/or chemical treatment to improve usage possibilities. Certain supplements can also provide added advantages. Not only economical and environmental but also nutritional motivations encourage a wider use of by-products in animal feeding. Extra descriptors: by-products; ruminant feeding; warm climates. Introduction Using agricultural by-products to feed livestock reduces feeding costs and environmental pollution. This practice is particularly advantageous in climates unsuited to the cultivation of traditional roughage crops; these include the European Mediterranean area and all the warm climate ones in the developing countries. If the use of these by-products is to be economically viable additional transportation and transformation costs, if any, must be kept to a minimum. By-products from warm climates Agricultural by-products for the feeding of animals can be divided into three categories: - fibrous by-products - vegetable by-products of agro-industrial origin - by-products of animal origin. In warm climates fibrous by-products are the most widely available. Unfortunately, acommo n feature is reduced nutritional value because of their high fibre content, lignin in particular; straws and the residue from olive processing are an example. For improved use of fibrous by-products, these should be treated to increase their nutritional value, e.g. with sodium hydroxide, ammonia etc.. The positive results which can be obtained from these techniques are common knowledge but, because of the considerable costs involved, widespread application in developing countries is improbable. For the present it would appear more feasible to use the straws and stovers as they are, or at the very most favour their intake with humidification and cutting (El-Naga, 1989). To improve the use fibrous by-products it is important to supplement the rations with other feeds. This is particularly so when these are locally available. Interesting results were obtained by Beramgoto (1989) who compared 3 diets, fed to beef cattle, with different percentages of corn stover. The animals fed on the diet containing the smallest percentage of corn stover (diet 1) showed daily gain of 859 g compared with the 742 g and 214 g of the animals fed on diets 2 and 3, containing decidedly higher 126 percentages of corn stover (Table 1). Table 1. Intensive fattening rations with various levels of corn stover and major agro-industrial by-products of Cameroon. Beramgoto 1989.

Feedstuff Rati ion

l 2 3

Corn stover (%) 20.0 40.0 80.0 Rice polishing (%) 40.0 23.5 10.0 Palm kernel rake (%) 34.0 22.5 0.0 Cottonseed cake (%) 3.5 11.5 5.5 Urea (%) 0.0 0.0 2.0 Mineral mixture (%) 2.5 2.5 2.5

Nkhonjera (1989) observed an increase in dairy cow milk yield, from 7 to 16 kg head/day, when a urea (1%), cottonseed cake (25%), molasses (10%), maize bran (61%), monocalcium phosphate (2%) and salt (T.0%) concentrate was used instead of just maize bran. Table 2. Effect of different supplements on the voluntary feed intake and TDN content of corn stalks-based diet. El Naga 1989.

Added supplement Voluntary feed intake TDN (g/head/day) (% on d.m. basis)

l.No supplement 563 54 2.1% urea and 0.1% vit. A 706 55 3.30% concentrate 832 56 4.Treatment with 5% urea 814 54 5.Treatment with 5% urea + 1.5% urea + 3% molasses 920 56 6.Treatment with 5% urea + 0.3% phosphoric acid + 0.1% minerals 774 54 7.20% concentrate mixture + 1% calcium carbonate + 0.1% minerals 1003 56 8.5% linseed meal 968 55

On the subject of supplementing fibrous by-product diets, Ef-Naga (1989) observed in male sheep fed oh diets of treated corn stovers, supplemented with various products, that the addition of 1 % of urea increased feed intake by 25%. When combined with urea treatment feed intake increased by 63%, though the best results were obtained by adding a percentage of concentrate (20%) consisting in cottonseed meal, corn, wheat bran, rice bran, molasses, salt, calcium carbonate and mineral supplements of bone meal, magnesium sulphate, ferrous chloride, manganese oxide and zinc oxide (Table 2). In Mediterranean countries there is a widespread availability of by­ products from olive processing (e.g.oliv e cakes and vegetation waters). 127 These can be used, at least in part, for animal feeding. These areas also have considerable quantities of olive twigs; these can be cut and stored in silos. The high fibre content (26% d.m.), AOL (17.2 d.m.), low protein content (6.48% d.m.), also characterized by an extremely low digestibility coefficient (2.01), discourages from using this alone, even in diets for sheep and goats (Vonghia et al., 1987). The use of a by-product from the purification of vegetable waters, obtained through "crioconcentration" with a 14.1% ether extract, 11.1% protein, 1.88% fibre and 29.94% ash content, in beef cattle diets, determined an improvement in feed efficiency and a variation in the acid composition of deposited fat with an increase in the oleic acid percentage and a decrease in palmitic and linoleic acids (Piva et al., 1988). Certain supplements and treatments also improve possibilities for the use of these products. A notable improvement in the digestibility of olive twigs was obtained with the addition of concentrate or other by-products, such as undecorticated safflower oilseed meal (Pinto et al., 1989). The main problems in the use of olive twigs derive from low digestibility of the dry matter (30-35%) and reduced availability of nitrogen as this has a 75% link to ADF. Nor should the possibility of finding relatively high percentages of tannins and phenols be undervalued as these may inhibit the ruminai cellulotic activity. The digestibility and nutritional value of olive twigs can be improved with alkali treatment (sodium hydroxide or ammonia) (Nefzaoui & Van Belle, 1986).

Table 3. Inclusion rate of some by-products in beef and dairy cattle rations. Values in parentheses are not referenced and are based on feed industry experience. Boucqué & Fiems, 1988.

By-product Inclusion rate (%)

beef cattle dairy cattle

Almond hulls 30 25 Citrus pulp 25-40 40 Coffee pulp 10-20 10-20 Coffee grounds 10-20 10-20 Cottonseed hulls 10 25-30 Cottonseed meal 05) (15) Distillers grains with solubles (30) (40) Grape pulp 15-20 (15-20) Grape seed oil meal 10 (10) Rice bran 15 (15) Wheat bran 20 r (35)

Table 3 gives indications for the use of certain by-products not recorded here.

Nutritional motivations Beside the economical motivations justifying abundant use of by­ products to feed animal in warm climates marked by a poor economy, nutritional reasons have also emerged from studies of the degradability of proteins, endocellular carbohydrates and constituents of the cellular walls,

128 and of the feed turnover which justify the introduction of by-products into ruminant diets. Interesting results were obtained by De Visser and De Groot (1980). They fed dairy cows on concentrates containing small or large quantities of starch and sugars, 217 and 410 g/kg respectively, obtained using greater amounts of by-products or cereals; they observed the higher ruminai pH values after the administration of concentrates containing considerable quantities of cereals. It can be supposed that the use of by-products with a high NDF content maintained the ruminai conditions more constant and favourable to the ruminai cellulolitic activity. The positive influences on ruminai fermentation were reflected in the milk yield. When the percentage of by-product in the concentrate dropped, there was a decrease in the milk yield and milk fat percentage with no change in the protein level of the milk. Accurate knowledge of the degradability both of the different fractions of carbohydrates and the protein is therefore extremely important. The use of by-product should not be considered penalizing but, on the contrary, may lead to a more physiologically correct feeding of the animals.

References

BeramgotoT. , 1989. The feeding value of some agro-industrial by-products for beef cattle at Bambuicentre . In: Proceedings of the fourth Annual Workshop held at the Institute of Animal Research, Mankon Station, Bamenda,Cameroon , 20-27 October 1987 African Research Network for Agricultural By-products (ARNAB), Addis Abeba, Ethiopia, p. 204-217. Boucqué CH.V. & FiemsL.O. , 1988. Vegetable by-products of agro-industrial origin. Livestock Production Science 19: 97-135. DeVisse r H. & De Groot A.M., 1980. The influence of the starch and sugar content of concentrates onfee d intake, rumen fermentation, production and composition of milk. In: Proceedings of the IVth International Conference on Production Disease in Farm Animals, Ed. D. Giesecke, G. Dirksen and M. Stangassinger Munich Tierarztliche Fakultät der Universität: 41-48. ElNag a M.A., 1989. Improving the intake and utilization of by-product-based diets. In: Proceedings of the FourthAnnua l Workshop held at the Institute of Animal Research, Mankon Station, Bamenda, Cameroon, 20-27 October 1987, African Research Network for Agricultural By-products (ARNAB),Addi s Abeba, Ethiopia, p. 354-362. Nefzaoui A. & Van Belle M., 1986. Effects of feeding alkali-treated olive cake on intake, digestibility and rumen liquor parameters. Animal Feed Science and Technology 14: 139-149. Nkhonjera L.P., 1989. Strategies to overcome constraints in efficient utilization of agricultural by-products as animal feed. In: Proceeding of the Fourth Annual Workshop held at the Institute of Animal Research, Mankon Station, Bamenda, Cameroon, 20-27 October 1987. African Research Network for Agricultural By­ products (ARNAB), Addis Abeba, Ethiopia, p. 105-113. Pinto F., Vonghia G., Ciruzzi B., Montemurro 0. & Marsico G., 1989. "Invivo " digestibility and nutritive value of undecorticated safflower oilseed meal, hydraulically extracted, of two mixtures made up of almond hulls, olive twigs and safflower oilseed meal. In: Second International Safflower Conference 9-13 January, Hyderabad, India: 3:12. Piva G. Masoero F., Uberti P. e Morlacchini M., 1988. Suli'utilizzazione alimentäre del crioconcentrato delle acque di lavaggio delle olive. Atti Société Italiana di Buiatria 20: 575-586. Vonghia G., Ciruzzi B., Marsico G., Pinto F. & Melodia L, 1987. La digeribilità ed il valore nutritivo di miscele a base di frasch e di olivo e di mangime composto integrato. Scienza e Tecnica Agraria 6: 213-222.

129 Suitable Engineering Strategies For Livestock Shelters In Warn Cliaates

Adolfo GUSMAN Agricultural Engineering Institute,Universit y of Viterbo

Angelo CANDURA Farm Building Institute,Universit y of Bari

Summary Inman y cases,simpl e equipment and traditionalbuildin g technologies can be used to solve theproble m of developing livestock shelters in which environmental conditions allow theanimal s to yield production. Evaporative cooling systems seem to be especially useful when temperatures are high fora long time and relative airhumidit y is in a range of 30%. Heavy traditional materials, in spite of their high thermal conductivity, can create useful barriers against the access of considerable thermal energy impulses originated by air temperature and solar radiation. Lastly, a number of useful solutions isexamined , which allow to further protect thebuildin g from solar radiation.

Introduction

The development of animalhusbandr y in warm climates meets with various difficulties and obstacles mainly due to the low tolerance to high air temperatures on thepar t of animals,an d especially by those species typical for temperate or cold areas. The most obvious consequence in these situations is a drop in productivity which, according to some researchers (Berry, 1964; Hann, 1977)an d for some breeds isa direct function of air temperature. There may be different solutions to thisproblem , but surely they include also the correct shelter design so that animals can find acceptable environmental conditions. In these regions, there areman y problems tocreat e themos t suitable environment into a livestock shelter and these problems are quite different and, under some aspects,ne w if compared with the situations one isaccustome d to inothe r climates where, for instance, protecting the animals from cold is thepredominan t aim, therefore it is necessary to reject any temptation to transfer into these areas the engineering solutions and technologies developed in temperate regions. In warm climates the problems to be solved are basically two: protection from high air temperatures and shield from the intense solar radiation. Air temperature and solar radiation reach their peak values almost at the same time,bu t they can affect the confined environment in different ways, and therefore different building techniques and equipment may be necessary.

Protection from hieh air temperatures

The upper critical temperature level foranimal s usually bred in temperate regions ranges froma minimu m of 25 °C for rabbits, to a maximum of 38 °C forbigge r animals like cows and inregion s located at latitudes lower than 30', these limits are easily reached and exceeded

130 byai rtemperature ,a tleas tdurin gdaytim ei nth ehottes tperiods . So it is necessaryt oprotec tth eanimals , sheltering them in a building at a lowertemperatur etha noutside : nowadays this is no longera technica lproble mbu tmerel ya neconomi cone . The solutionsusuall yapplie di nth ecivi lan d industrial buildings involve installation and managementcost sto ohig h to be borne by breeders; moreover,equipment sar e producedb ymean so f sophisticated technologiesquit edifficul tt ob eouse di na rura lenvironment . Other solutions should rather be sought, which, besides being cheaper,ca nb emanage da trura lenterpris elevel . Asprotectio nfro mhig htemperatures ,tw oinstance sar epossible : -ai r temperaturehighe rtha ntoleranc elevel sfo ra lon g time during theday ; -ai r temperaturehighe rtha ntoleranc elevel sfo ra shor ttim e during theday . a)Ai rtemperatur ehighe rtha ntoleranc elevel sfo ra shor ttim e during theday ; This casei sals oth emos tdifficul tbecaus eth esimpl e technologies arerathe rmodes tan dlimite di nuse . Thesimples tmean swhic hcoul db euse dar ethos ewhereb yai ri scoole d byexploitin git ssensibl ehea tt oproduc ewate rvapor . , Evaporative coolingan ddirec twate revaporatio nequipment s fall in this category,bu tbot har eonl y usableunde rdr y climate conditions andi fsufficien twate ri savailable . In verydr yenvironmen t (r.h.< 30%), iti s theoretically possible, with aperfectl yadiabati cprocess ,t oreduc etemperatur eb ymor e than 35%, and,takin gint oaccoun ttha t modernfilterin gmaterial sca nreac h an efficiency as higha s80% ,i ti sno ta t all difficult to lower outsidetemperatur emor etha n30 %(Fig.1) .

50T - R.H.

— 20% — 30« -*-40% -e- 50% — 60% -*-70% -•-80%

50 C Fig.1 air temperature

Inth ecas eo fa shelte rfo rmil kcow swher etemperatur eshoul dno tb e higher than3 5° Can drelativ ehumidit yshoul dno texcee d9 0% , if we held theheat-productio nalgorithm sdevelope db y researchers (Landis, Bruce,Erikson ,Stro me tal. )fo rNort hAmerica nan dEuropea nbreed s to be valid, then witha flo wrat eo f10 0m / han d an average thermal insulation ofth eshelte rstructure so f2, 0W/ m °C,i ti spossibl e to

131 withstand outside air temperatures as high as 41 °C, provided that relative humidity is not more than 30% (Fig. 2).

C « flow rate

-+- 75 cm/h x ^ , d Ö head E-^-- *S-^^*'' -*- 100 cm/h x •""!-•—"' \~*z% y*^- head ^p^^ -e- 150 cm/h x ^%^ 'f*' head -«-,200 cm/h x head

—•"

28- ——, 35 36 37 3a 39 « 41 « « 44 45 46 47 48 49 50 Fig.2 outside air temperature'

Another systemmake sus eo fth edirec tevaporatio no fth ewate r into theshelte rb ymean so fsprinklers ;her eth esam ephysica lprincipl e of evaporativecoolin gi sused ;sprinkler sanywa yar eles swidel yuse d for thefollowin greason s: -no t allnebulize dwate ri stransforme dint ovapor ,bu ta par t of it dropso nth eanimals ,thu scausin ga nannoyin gdripping ; - iti snecessar y thatindoo rai rtemperatur ei ssufficientl yhig ha st o turn waterint osteam ;if ,instead ,evaporativ ecoolin g systems are used, theai rintroduce dint oth eshelte ri salread ycooled ; - theus eo fsprinkler si sno talway seasy ,especiall y ifth ewate ruse d isno ttotall yfre efro mimpurities . b)Ai rtemperatur ehighe rtha ntoleranc elevel sfo ra shor ttim e during theday . Ifai rtemperatur eexceed sth etoleranc elimit so fanimal sonl yfo r a short period oftim e(generall yfo ra fe whour saroun d midday), then it is possible tocontro leffectivel y the environmental conditions thankst osuitabl ebuildin gtechnologies . Inthi scase ,th erisin go fexterna ltemperatur eca nb ecompare dt oa n energyinpu tvariabl ewit htim ean dwit hver ymarke dgradients .I norde r tob eabl et oaffec tth econfine denvironment ,thi senerg ymus t somehow penetrate insidei tan draise sth eenerg yleve lo fal l inside masses, includinganimals . Assumingjus tfo ra momen ttha tther ear en otherma lexchange sdu e to ventilation,th etemperatur ei nth eshelte rwil lbegi nt oris ewhe n the inner face of thehorizonta lan dvertica l structures will reach a temperaturehighe rtha nai rtemperature . If we assume, for thesak eo fsimplicity , that the outside air temperaturevarie saccordin gt oa la wo fth etype : T= T ra+ AoSe n£2 t where: -A 0= oscillatio namplitude ; -ß = pulsation; -T m= averagevalu earoun dwhic htemperatur eoscillates ,

132 the temperature ina n inside point of the structure, at a distance x from the outside wall face,afte r a time t, will take avalu e expressed as follows: „ Tx = Tm + Ase sen(flt- ßx) (1) where ß has an expression of the type: ß = dV n /t0D = C jo c/r where: - k = structure density; - c= specific heat of the structure; - r = thermal conductivity of the structure; - to = period of the sinusoidal law. So some time it isnecessar y inorde r that the temperature of inner faces of structures begin to rise and this time isa function of the characteristics of thematerial s (coefficientß) . Inou r opinion, themos t advisable strategy for reducing the negative effects is to extend asmuc ha s possible theduratio n of this transient period, so that steady regime conditions indoorshav e not yet been reachedwhe n the outside temperature begins to descend. So, inorde r to slow down the phenomenon, it isnecessar y that: - the structures of the building should have a very high thermal inertia, inorde r todela y the entrance of thermal energy; ' - these structures shouldhav e a thermal capacity (c * 6)allowin g them to store excess thermal energy and to release it when environmental conditions aremor e favourable; - the masses inside the building shouldhav e a very high thermal hysteresis; - the average thermal transmittance of the structure should be low enough as to limit the thermal flowbetwee n indoors and outdoors, if a steady regime is reached; - the ventilation rate during theseho t periods shouldb e the minimum necessary to ensure thevita l air for the animals, so as to prevent massive amounts ofwarme r air from entering the building; - the specific building volume per animal should be such as to limit ventilation rate tover y lowvalues . These objectives canb e achieved by usingbuildin g materials with the highest possible thermal capacity, and by adopting architectural solutions envisaging ahig h specific volume, even to the detriment of an increase of the structural surfaces. Some experiences carried out at theFarmbuildin g Institute of Bari, on an experimental poultry-penbuil t with traditionalbrickwork , with a specific dispersing surface equal to 0,56 m per animal, larger than standard shelters by 50%a t least, evidenced (Fig. 3) that inside temperature reached, at themost ,value s equal to the outside,wit h an average time lag of more than 5,0 hours, although no mechanical ventilation equipment was provided.

Protection from solar radiation

The daily amount of solar energy inarea s lying at a latitude of less than3 0 C is fairly uniform all year roundhig hvalues . But, as it is well known, the peculiar characteristic of this phenomenon lies in itsvariabilit y in the course of the day, so that the effects on the structures may stillb e considered as high-intensity energy input. The effects of radiation on awal l exposed to sunlight can be considered as equal to those induced on the same wallwhe n the external face reaches a temperature:

133 TF= T X+ AE/a '+ Hx/a'CTj .- Tj ) where: -T j= outsid eai rtemperatur e ; -a =sola rradiatio nabsorptio ncoefficien to f theexterna lwal lfac e -H y= radiatio n factor of saidfac e -E = sola rradiatio n -a '= limina ladductio ncoefficien t of thesai dfac e -T r= averag eradiatin gtemperature ; which is obviously different fromth e temperature reached by the externalfac eo fa wal lexpose dt osunlight .

C 32T

iai r temperature

II II I -I I I I I > I I I I I IH I I I I I I 2 4 6 B 10 12 14 16 IB 20 22 24 hours Fig. 3

Due toth eheatin go fth eexterna lface ,th etemperatur eo fth e wall rises init svariou slayer saccordin gt oa la widentica lt o the above mentionedon e (1), duet oth efac ttha tradiatio nvarie sove rtime . Since the pattern is periodic, the coefficient ß is crucially important, andthi si sa direc tfunctio no fth especifi cweigh tan d of the specific heat ofth ematerial ,an da n inverse function of its thermalconductivity . Therefore the mostimportan tproble m tob esolve di st o find heavy materials, which, although havinga hig h thermal conductivity, are featuredb ya hig hspecifi chea tvalue . In otherwords ,th emateria lshoul dhav ea hjg htherma l inertia (Vô c/r), becauseth egreate rthi sinertia ,th egreate rth edela ywit hwhic h thetherma lwav ereache sth einsid eenvironment ,an dth egreate rwil lb e thedampin gundergon eb yth etherma lwav e (representedi nth eexpressio n (1)b yth eter m P^e ). Certainly in thissituatio nth eweight so fth e structure materials play animportan trole ,s otha tth eus eo fmoder nmaterial s- although featured bya ver ylo wvalu eo ftherma lconductivit y- doe sno t appear veryadvisabl e inthes econditions ,wherea straditiona lmaterials , such as stone masonry, heavycoverin g materials etc., are particularly suitable. A research carried out duringsumme r in Southern Italy on an experimental poultry-pen built with traditional limestone masonry,

134 evidenced that,although hth ewall swer eno tver ythic kan dth ecoverin g was atile-linte lroof ,th ewall sstruc kb ysunligh tcause dtim e lags inth etherma lwav erangin gfro mlittl emor etha n3, 0h t omor etha n8, 0 h, and dampingvarie dfro mlittl emor etha n1, 5 timest omor e than 3 times,a si ti sshow ni nth efollowin gtable :

Probe Damping (No.o ftimes ) Time lag(h ) June July Aug. Average June JulyAug .Averag e

East1 m t 3.21 3.31 3.15 3.22 7.0 6.0 6.5 6.5 East2 m t 2.08 2.20 2.07 2.12 8.0 9.0 9.0 8.7 North1 m t 1.81 2.03 2.08 1.97 3.0 5.5 6.0 5.8 North2 m t 1.54 1.65 1.87 1.69 6.0 7.0 7.0 6.7 West2 m t 3.66 3.41 2.97 3.35 3.5 3.5 3.0 3.3 Covering 2.68 2.90 2.91 2.83 3.0 4.0 4.0 3.7

The experimental shelterconsidere dwa sonl y equipped with natual ventilation, thereforeon eca nreasonabl yassum etha twit h an energie mechanical ventilation or,i fpossible ,wit hth e use of evaporative cooling,a furthe rdro pi ntemperatur ewoul dhav ebee nattainable .

Furtherbuildin gmethod sfo rimprovin gprotectio nfro msola rradiatio n

Fromthes eexperiences ,othe rreflection san dsuggestion sarose ,whic h canb eimplemente di nconjunctio nwit hth eengineerin gstrategie s just outlined, inorde rt oimprov elivestoc kshelter sprotectio nfro m solar radiation. Theenerg ystrikin gth ebuilding' sstructure si ssubjecte dt oth elaw s ofoptic s: therefor ea grea tpar to fthi senerg yca nb esen tbac kt oth e surrounding environmentdu et oreflectio ni fth estructure s have good reflection characteristics and low absorbing power (light-coloured structures). In theabov ementione dexperience si tturne dou ttha tth e difference betweenth egre ycolou ro fcemen tplasterin gan dth edul lwhit eo flime - wash paintinginvolve sa dro pb yabou t55 %i nth etemperatur e increase onth eoutsid ewal l (Fig. 4). Moreover, if weconside rtha ti nwar mregion s the solar radiation incidence angle takes very lowvalue s (rays have a near-vertical direction),an dtha tthi svalu eshow sa lesse rseasona lfluctuatio nove r time, iti spossibl et oincreas eprotectio nb ysimpl y lengthening the roof projection so ast oshado wth e vertical structures. Furthermore, as most solarenerg yi sconcentrate d in the visible spectrum,attentio ni st ob epai dt oth eshelte rwindows ,les tthe y are transformed into dangerous solar energy catchers, thus causing greenhouse effects in anenvironmen twhic hmos t certainly needs no furtherenerg yinput . Finally, theabov eexperience shav eevidence dtha tth eprotectio n of the building coverplay sa crucia lrol ei nlimitin gth e energy input intoth eshelter . In Europeanan dNorth-America ncountries ,th ecove ri sconsidere d as "a sorto fha tplace do nto po fth ebuilding" ,t oprotec ti tfro m cold andtherefor ebuildin gtechnologie sar eoriente di nthi ssense . Unfortunately iti sno talway spossibl et ous ematerial sfeature d by high thermal inertia,becaus ethei rweigh twoul drequir e very strong structures ; thereforei ti snecessar yt ocoo lth eoute rfac eo fth ewal l eitherb ymean so fwater ,o rb ycreatin ga circulatio no fles swar m air

135 40T

wall faces

— outsidefac egra y colour -*-insid efac e -+-outsid efac edul l white -e-insid efac edul l unite

hours Fig. 4

-if possible - underneath it, taking it from inside the shelter or from pipes stuck into the ground, if the ground temperature at a certain depth is lower than external temperature.

Conclusions

In regions featured by very warm climates, livestock shelters can effectively contribute to the development of breeding activities, provided that suitable building systems and equipment are used. Simple technologies may allow to limit thermal excess in the shelter, which could be detrimental for the productivity and survival of animals. Certainly, unless high installation and management costs are borne, it will be impossible to create the ideal conditions for breeds coming from more temperate regions, but a close cooperation in the efforts of breeders and engineers will make it easier for the future to overcome the obstacles which in warm regions prevent a profitable animal husbandry.

Reference

AA.W. 1984 Climatization of Animal Houses. Working Group of C.I.G.R.

Berry, I.L., M.D. Shanklin and H.D. Johnson. 1964. Dairy shelter design based on milk production decline as affected by temperature and humidity. Trans, of the ASEA 7,3: 329-331.

Candura A., Gusman A. 1980. Periodic heat flow influence on planning criteria of farm buildings in southern Italy. Conf. II Section C.I.G.R, Winterthur.

Hann G.L. 1977. Livestock environment selection for hot climates. FAO Working Paper W/L 0286, FAO/SIDA conf. on Storage and Structures in Developping Countries, Nakura, Kenya.

136 Preservationo f animalecotype sbre di nth eMediterranea n area

D. Matassino & F. Grasso

Dipartimento di Scienza délia produzione animale - Université degli Studi di Napoli 'Federico II' ViaUniversité ,10 0 80055 Portici - ITALY

Summary

The fundamental role played by local animal populations has been pointed out and the possibleheav yconsequence s of theirextinctio n underlined. The complex issues concerning the preservation of animal germ plasm on the way to extinction have been dealt with. The marked, detectable genetic variability offers wide opportunities to improve the reproduction and production wide opportunities to improve the reprodution and production performances of ecotypes. Or rather, the remarkable production performances of some ecotypes pose the question whether it is worth-while that they undergo a specific selection (Nardone and Matassino, 1989). The need has been stressed to know the population to be safeguarded by means of research in order to achieve its' biological characterization. In this context, the aims of the newly founded 'Centre for the preservation of animal genetic types of zootechnie interest on the way to extinction' at Circello (Benevento) have been synthetically explained. It hasbee n pointed out that thepreservatio n of genetic resources can not be an end in itself but must beth epresuppositio n for thezootechni eexploitatio n of thepreserve d genetic resources. This exploitation must depend on the human population's changing needs and on the trends forecast for the future.

Introduction

Until recently the fundamental role played by local animal populations in the territory exploitation has been widely underestimated. As a matter of fact, man's only aim has been that of boosting production. Therefore, thediffusio n and breeding of the genetic types with a higher productive potential has been fostered by all means. This trend has unavoidably led to a progressive neglect of and, therefore, to an increasingly sharper reduction in the numbers of local livestock. As a result, in many cases local populations are threatened with extinction while, in others, they have already disappeared. Only beginning from the '70s, the problem of defending and exploiting animal genetic resources has come to the attention of researchers and zootechnie operators. A FAO/UNEP project, aiming at determining the animal genetic types in danger of extinction, was particularly useful in this sense. Within this project, in 1984 a EAAP team, formed by Maijala, Cherekaev, Devillard, Finzi, Reklewski, Rognoni, Simon and Steane,publishe d data concerning Europe. In addition,a n EAAP/FAOdat a bank wasse tu p inHannove r regardinganima l geneticresources . Table I shows some species of local genetic types bred in the Mediterranean area (45th parallel North and 28th parallel South; 10th meridian West and 44th meridian East, as suggested by Nardone and Villa in 1990). Local animal populations result from adaptive changes occurred over hundreds or thou­ sands of years.Sinc e such changes caused genetic modifications useful to the achievement of an increasingly greater adaptability of these populations to the varying environmental conditions, it isclea r that their total extinction would do great damage to the community (Matassino,1979 ; Boyazoglu, 1990). Therefore, it has been many times suggested (Matassino and Pilla, 1976) eliminating animals only for actually sound reasons. In fact, little is known about animal individuality, as a result of insufficient information on gene action and interaction patterns. On the other hand, the remarkable contribution of local cattle genetic types in the Mediterranean area is not to be underestimated either, as shown by Nardone and Villa (1990). In the 18

137 TabicI -Som eautochthonou sgeneti ctype so f the Mediterraneanarea .

Spede s Country cattle 0 horse pi« sbeep goat

Albany Albanian Albanian Albanian LaraPousi Albanian Mursi Mao' Kuda Shkodra Cyprus Cyprus Berkshire Awassi CyprusWhit e Cyprus Peratiki France Abondance Auxois BasqueBlac kPie d Bizet Poitou Aimorican* Boulonnais Corse Caussesd u Lot Rove Aubrac Créole Charmotte Aure St. Giron Gascony Lacaune Bazadaise Limousin Lourdes Béarnais Merinod'Arle s Breton BlackPied * Noire duVela y Camargue Prcalpesd uSu d Fromentd uLéon * Taïasconnaise GasconneAnSolé e Lourdaise Saters Tarentaise VillarddeLans

Greece Greek Shorthom Greek GreekLoca l Kymi Greek GreekStepp e Skopelos Keas* Zakynthos Tinos*

Israel Oksh* Awassi SyrianMountai n Ak-Karaman Arabi

Italy Agerolese Bardigiano Calabrese Bagnolese Aquilana Cabannina* déliaGiar a Casertana Corneliabianc a Cilentanagrigj a Catvana Maremmano Cintasenese Fabrianese Cilentana fiib/a Gnisara Murgese déliaBasilkat a Finarda Cilentananer a Garfagnina Saknùtano-Persano délieMadonf e Frabosana Ciociaragrigi a Maremmana Tolfetano Sarda Garessîna Cosentina Modenese* Garfagninabianc a Molisana Modicana Laûcauda Napotetananera Pisana Matesina Teramana Podolica Mosciacalabres e Venticanese Pontremolese Quadrella Reggiana* Sambucana Romagnola Turchessa Saida SardoModican a

Lebanon Lebanese

North Africa Baladi Algerianara b Berber (Algeria, Egypt, BruneAtla s Barbary Egyptian Libya, Marocco, Damietta BeniAhsen Libyan Tunisia) Guebna BeniGuil Mzabäe Libyan Berber Nubian Maryuti MiddleAtla s Saidi Montbéliard Tadla Oufanes Blond + Saidi Tadla*

Portugal Alemtejana Garrano Cekic Bordaleiro Arouquesa Iberian Barrosa Frisia* Galeea Madeira* Marinhoa Maronesa Mertoknga Mirandesa

138 follow tableI

Species Country cattle(1 ) | bone | pi« | sheep | goat

Syria Damascus Damascus Oksh* Shami Spain Acastmado GalicianPony Andahisian Alcarrena BiancaAndaluz a Alistana- Sanabres a BlackCasoUa n Canaria BiancaCelüberic a Asturianamoatan a Catalan fiitrllnnfl Canaria Asturianad elo svalle s Extremadur a Chum DelGiiadarram a Avikaanegra * GalicUtt Gallega Malaguena Berrendae nColorad o Maforcan Guirra Muroana-Granadina Benendae nnegr o Vnoria Lacha VeratayRcunta- BiancaCaceren a Mallorquina -Extremen s Caldelana Mancnega Canaria* Montesma CardenaAndaluz a Ojalada Chachena RasaAragones a DcUdiâ* Ripollesa GanadoBrav o Segurena Limiana Talaverana Menorquma Vasca Monchuia Morucha Murriana NegraAndaluz a PajunaAndaluz a Pafmera* Pirenaica Reunta RuMaGallega / Sayaguesa* Tudanca Vianesa Zamora Turkey Boz AnatolianNativ e Awassi AnatolianBlac k EastAnatolia nRed * Malakan Degüc Angora KaracabeyBrow n Uzunyayla hnroz Abkhasian NativeBlac k Karakul Mingrelian NativeSouther nYello w KiviMik Plevna RedKarma n SouthAnatolia nRe d Yugoslavia Busha BlackSlavoni c Bovec Gacko Krshkopolje Pramenka IstrianGrey Mangalitsa Sokava Siska Tsigai Sumadija Turopolje

( )Geneti ctype squote db yEAA PCommissio n'System so fbovida e productioni nm eMediterranea nArea '(Nardon ean dVilla ,1990) , except thosemarke dwit h *.

Europeancountrie smilke dloca lcow saccoun tfo r 47%o fth eoveral lnumbe r of bred cowsan d for 17% of the total milk production. Thecontributio n of local populations to meat production is also remarkable. In Italy there are goat ecotypes the annual milk production of which varies from 150 to more than 3501 in 180day s of lactation (Matassino etal, 1989a and 1990a), with individual peaks that can exceed 6001 .Othe r studies (Matassino etal, 1989&)showe d that the quality of the meat supplied by Podolian free-grazing cattle is highly competitive to that of Friesian or Brown cattle and their derivatives kept in intensive conditions.Suc h results become moreimportan t if weconside r that sofa r nogeneti cimprovemen t action hasbee ncarrie d out on suchbiotypes .

Fundamental issues

Which are the problems linked to the preservation of animal germ plasm on the way to extinction? We believe that giving an exhaustive answer to this question is impossible, the problems to solvebein g theoretically countless.A sa matter of fact, real events are continuously different and, therefore, dynamic. For instance, some of the issues that, in actual fact, concern all animals can be synthetized as follows (Matassino, 1989a): (a) which phenotypic expressions ('traits') are worthy being either preserved or changed and which are the limits to such changes; (b) which parameters should beuse d for measuringth echang ei n oneo rmor ephenotypi c expressions; (c) how much importance one will have to attach to the knowledge of all the rules regulating the relations

139 between animals and between them and their breeder; (d)whic h analytical instruments are to be used for the semantic scan of the changes in a phenotypic expression; (e) which is the role played by adaptation and by the changes in the interactive process between the genotype and the environment; (ƒ)ca n the availability of a great number of local genetic types be useful to the achievement of productions having qualitative features that, to a greater extent, meet consumers' needs in relation to the continuous changes in life-styles; (g) which differentiation level must distinguish one ecotype from another; (h) which will be the influence of innovatory biotechnics on safeguard actions; (i) how to interact effectively with breeders who can be defined 'animal geneticists with operative tasks'. Suchproblem s will be solved only through a systematic approach. Preserving the animal germ plasm is an issue of public interest, that must be dealt with depending on a serieso f future trends. It is necessary to take these trends into account so that animal products meet man's nutritional physiological requirements in a satisfactory way. As a matter of fact, according to Matassino etal (19906), the human population will reach nearly 7,2 billion people by the year 2010, with a 2 billion increase as against today, and the demographicstructur e willchang ei ntim eaccordin gt oag egroups . The increase in the population age and the change in life-styles will unavoidably affect the strategic food choices for the XXIcentury . The market demand will focus on safety products poor in cholesterol and sodium chloridebu trich i ncalciu man d fibres, easyan d quick to prepare, etc.. According to the above-mentioned authors, the human population in Mediterranean countries willpas sfro m 394 million peoplei n 1990t o44 8i nth eyea r200 0an d toabou t50 0i n the year 2010, showing a 27% increase over a 20 year period, with particular reference to the African (+50%) and Asiatic (+46%) areas. Again by the year 2010,th e human population will have to meet a protein requirement of 383,243 tons/day, at least half of which will have to be of animal origin. Therefore, within 20 years, animal production will have to be capable of supplying 69.942 million tons of proteins yearly. Considering that in 1985th e availability of these proteins was equal only to 42.526 million tons, the animal industry will have to produce another 27.416 million tons with different solutionsaccordin g to thegeographica l area concerned. Indeed, the possible methods for preserving the germ plasm of local animal population threatened with extinction can be the following: (a) preservation of gametes or zygotes; (fc) preservation of individuals: (»') in situ or (ii)extra situ. Some methods for the preservation of DNA catalogued sequences have been recently perfected. One must explain that preservation other than that of live animals, although it proves to be useful for rather short periods, is limited by the fact that (Matassino, 1989fc): (a) the initial gene set of the preserved zygotes will not be affected by environmental stress; (6) the preserved gametes may originate animals with unwanted adaptive capacities; (c) because of the difficulty in determining a really representative sample of the genetic variability of the existing populations to be preserved, high quantities of zygotes and gametes should be preserved. Someauthor s made estimates in order to define the minimum number of animals to breed with thepurpos e of preserving ageneti c type.Accordin gt oMaijal a (1984),th eminimu m number of breeding females topreserv e is: 1,000 for cattle, 500fo r sheep,20 0fo r swinean d goats.FA O stressed that, when a population amounts nearly to50 0breeding ' females (with a total of 10,000 animals), there exists the real danger of extinction. Therefore, it is necessary to carry out defence and safeguard initiatives following specific guidelines for singlecases . As stated also by Rognoni et al. (1990), obviously the preservation of local animal populationsmus tno tan d cannotb ea nen d initself ,bu tmus t represent thepresuppositio n for the zootechnie exploitation of thepreserve d seto f genes.Thus ,th eproductio n patterns tob e worked out must fully comply with dynamic and different realities for a rational management of local animal and vegetable genetic resources as well as water and land resources. In this connection, Nardone and Matassino (1989) suggested an example concerning dairy cattle in the dry subtropical areas. Given the peculiarity of this geographical area, the planned actions concerned: the animal genotype; cattle feeding; the availability and use of irrigation water; the demographic structure of bred animals; structures and infrastructures; technical advice;

140 services; cattle healt and breeders. In addition, Schemel • Centrefo rth epréserv aHo no f animalgeneti ctype so f zootechnie among the measures interesto nth ewa yt oextinction . aimed at boosting pro­ NATIONAL Economican dbiogeneti csafeguar do f different duction, the first-genera­ PLAN animalspecie s threatenedwit hextinctio n tion cross-breeding bet­ -Ministryo fAgricultur ean dForestr y ween local genetic and SPONSORS» I -Italia nBreeders 'Associatio n specialized dairy types -Tow no fQrcell o(Benevento ) is not deemed to be -Chairo fGenera lZootechnic san dGeneti c Improvement ofth eUniversit yo fNaple s 'FedericoH ' generalizable, as is often -Campani aRegio n suggested: for many populations the values of SEAT 'Casaldianni' Farm( 31 0ha )- Circeu o(Benevento )- ITAL Y some demographic para­ meters involved (live -Preservatio no fgeneti ctype so fzootechni e birth rate and rotation AIMS interesti ndange ro fextinctio ncomin gfro m Mediterraneanan dItalia nregion san dcollectio n rate) prevents the neces­ ofdat aconcernin ggenealogical ,reproductive , sary ecotype preserva­ productive,morphologica lan dhealt haspect s tion. -Stud yo fth ebiologica lcharacteristic so fth e above In order to exploit a local genetictype san dimprovemen to fth etrait s qualifying productionb ymean so dinnovator ybiotechnique s population, iti s necessary -Preservatio nan dmultiplicatio no fanimal scarrier so f to 'know' it and achieve Robertsoniantranslocation s its biological characte­ -Exploitatio nan dreclamatio no fth e so-called 'difficult' rization. The recent in­ neglectedarea s stitution of a 'Centre for -Availabilit yo fvaluabl egeneti cresource sfo rpurpose s the preservation of ani­ PROSPECTS ofzootechni eexploitatio n mal genetic types of -Sprea dan dapplicatio no fdat afro mresearc han dstudie s carriedou twit hth ecollaboratio no fnationa lan d zootechnie interest of the internationalresearc hinstitute s way to extinction' (Sche­ me I) at Circello (Bene­ vento) fits in with this approach. This Centre is concerned with the study of the biological characteristics of thepreserve d genetic types from Italian and Mediterranean regionsan d aims at their zootechnical exploitation by means of innovatory biotechniques. Some of them are dealt with in Scheme II while others in specific works (Matassino, 1988« and b,19896,1990) . The planned preservation and multiplication of ani­ S-..SemeI I- Embry omicromanipulatio n (Matassino, 1990). mals which are carriers 1.Availabilit yo fembryo s of Robertsonian translo­ 1.1.Embryo scollecte dfro msuperovulate ddonor s cations is of particular 12. Productiono fembryo sfro moocyte smature dan d interest. According to so­ inseminated'i nvitro ' me empirical studies, ISexing these animals show 3.Clonin g production parameters 3.1.Splittin g (conformation, growth 32, Nucleartransfe r rate, etc.) higher than 321.Blastomere s 322. Embryoste mcell s karyologically normal 3.23.Inne rcel lmas s ones (Matassino, 1984). 4.Gen etransfe r This chromosomic reshuf­ 5.Conservatio n fling becomes extremely 6.Productio no fchimera e important specially in the homozygous state. The decrease in the chromosomenumbe r(2 n= 58,56,etc.) ,wit hn oloss o fsemanti cinformation ,i sknow nt oentai la n increase in gene linkage and, consequently, an enhancement of the genetic variability that is indispensablebot hunde rnatura lselectio ncondition san dfo rth e implementation ofan ygeneti c improvement plan. Besides the linkage effect, translocation is thought to play an important role in the process of temporal adaptation and toimprov e the accuracy degree of chromosome segregation during meiosis, a positive relation having been shown between the chromosome

141 length and the absence of errors during segregation. The in vivo preservation and the multiplication of these animals has to be regarded as particulary useful, both because they could originate new species and because they represent a genetic material that could be widely used inth e future. The determination of genetic variables with observable effects will make it possible to detectan ycorrelatio nbetwee n thesegeneti cmarker san d production and reproduction efficiency parameters. Thus, a prompt determination of the individuals characterized by a higher degree of zootechnie suitability will be possible.Fo r instance, the study carried out on local goats from Molise (Matassino et ah, 1989a) and Campania (Matassino etal., 1990a) showed a significant connection between the milk production over 150 and 180 days of lactation and the pigmentation pattern, which resulted in production differences varying from 8 to 23%. Obviously, the results obtained as investigations go along will make it possible to effect phylogenetic analyses of the examined populations, an assessment of the heterozygosis degree of singlepopulation s and of interrelationsbetwee n genotypes and theenvironment ,etc. .

References

Boyazoglu, J., 1990.Salvaguardi a e valorizzazione delle popolazioni ruminanti autoctone, con particolare attenzione albacin o del Méditerranée. Alto Tammaro 2 (5):39-40 . '-' Maijala, K., Cherekaev, A.V., Devillard, J.M., Reklewski, Z., Rognoni, G., Simon, D.L. & Steane, D.E., 1984.Conservatio n of animal genetic resources in Europe. Final report of an EAAPworkin gparty .Livestoc k Production Science 11:3-22. Matassino, D., 1979. Intervento alia Tavola rotonda su 'Prospettive e misure per la difesa genetica delle popolazioni animali'. Proc. Meet. CNR 'Salvaguardia genetica e recupero zootecnico delle popolazioni autoctone italiane', Foligno,495-497 . Matassino, D., 1984. Lo sviluppo degli allevamenti dell'Appennino settentrionale: risultati di ricerche, strategie, mezzi di intervento. Proc. Meet. 'Lo sviluppo degli allevamenti nell'Appennino settentrionale', Salsomaggiore, 47-56. Matassino, D., 1988a. Lo sviluppo delle biotecnologie: aspetti scientifico-tecnici e prospettive per il futuro. L'Allevatore 44 (33)suppl. : 1-15. Matassino, D., 1988b . II futuro delle biotecnologie nelle produzioni animali: alcuni aspetti scientifici e tecnici.Produzion e Animate 1,II ISerie : 35-71. Matassino, D., 1989a. Le problematiche sul tappeto nel miglioramento genetico degli animali. Giornaled i Agricoltura 99(39) : 34-39. Matassino, D., 1989b. Biotecnologie: applicazioni e prospettive. Italia agricola 126 (3):101-122 . Matassino, D., 1990. Micromanipolazione embrionale per 1'incremento dell'efficienza riprodut- tiva dei bovini. Proc. Meet. 'Biotecnologie nella riproduzione e nella produzione animate', Stresa, 28 settembre. Matassino, D. & Pilla, A.M., 1976. Genetica e miglioramento degli ovini. Proc. II Congr. naz. ASPA,Bari , 17+20maggio ,229-262 . Matassino, D., Montemurro, N.,Zullo , A., Grasso, F. &Ramunno , L., 1989a. Studio sui caprini autoctoni del Molise. IV. Alcuni fattori influenzanti la galattopoiesi. Produzione Animate 2, III Serie:41-54 . Matassino,D. ,Nardone , A.,Grasso ,F .& Zullo,A. , 1989b. IIbovin o podolico:ieri ,oggi ,domani . Taurus 1 (6): 101-133. Matassino, D., Montemurro, N. Grasso, F. & Zullo, A., 1990a. Alcuni fattori influenzanti la galattopoiesi in caprini autoctoni allevati in un'azienda del Salernitano. Produzione Animate 2, IIISerie .I n press. Matassino, D., Zucchi, G. & Di Berardino, D., 1990b. Management of consumption demand, supplyan d exchanges.Proc .4 1 èmeRéunio nAnnuell eFEZ .Toulous e(France) ,8+1 2luglio . Nardone, A. &Matassino , D., 1989.1sistem i di allevamento bovino per la produzione di latte nel subtropico arido:alcun e ipotesi di intervento su larga scala. Produzione Animate 2,II I Serie: 1-23. Nardone, A. & Villa, E., 1990. Cattle resources in the Mediterranean area. Proc. Int. Symp. 'Livestock in the Mediterranean cereal production systems',Rabat , 7-10 ottobre. Rognoni, G., Gandini, G.C., Pagnacco, G. & Canavesi, F., 1990. Conservazione delle risorse genetiche in Italia: esperienze e prospettive di lavoro. Alto Tammaro 2 (5):46-51 .

142 CONCLUDING REMARKS Theprinciple s that liebehin d alllivestoc kproductio n systems inEurop e with which we are familiar apply equally to hot climates, as do all related technologies. We must recognize however thephysica l challege of climatic stress andal ltha t goes with it,an d also the parallel challenge posed by the fact that these countries are simultaneously developing countries, and therefore countries with a very special future and a very difficult present. In many cases, developing countries are now shifting from subsistence agricultural into much more productive agricultural systems, thus generating the labour and food surplus which makes possible both industrial and general economic development. Developing countries today areactuall y moving ata faster pace through this phase than was donei nEurope . Three broad groups of technical issues have arisen during the meeting: firstly, the breeding aspect; secondly, the management of animal physiology; and thirdly the nutritional technology for animal feeding. These, of course, interact with each other, and alternative classifications could be found. The biggest single form of change has been breed replacement throughout ourcattle , pig,an dt oa lesser extent sheepan d goat populations. Thebul k of thebree d types on which work is carried outtoda y arei n fact not native of the country in which they are used, but have been introduced in recent generations. ' It must berecognize d that things areno t static and that wecanno t deny developing countries the opportunity to utilize the variability of genotypes, whether between or within breeds. No doubt, in many cases, this is already happening with breed replacement, althoug we must be aware of the need for further improvement of local breeds. On the other hand, some interventions at the genetic level may be counterproductive where the system is so finely balanced in its environment that the main challenge ison e of survival. Regarding physiological questions, the two opening papers by Drs. El Shafie and Webster demonstrate the complexity of physiological response to animal stress. The simplest measurement of heat stress is obviously the increase in body temperaturean d every experiment should report rectal temperature and its response to environmental changes. A well conducted experiment byDr . Bertoni onphysiologica l responses in sheept o shade wason eo f thefe w papers, in fact, in which weha d specific experimental results and it shows just how professional you need to be in order to reach sustainable conclusions. The greatest challenge lies in the world's pastoral areas. These are by definition marginal - usually with toolittl e rainfall for crop production. However, thearea s make up half of the world agricultural area. The human populations concerned are usually more dependant on single entreprises than inmor e mixed farming systems elsewhere. We can improve such systems in several ways, for example, through reduction of losses by improving animal health conditions, or better adjustment of biomass, both animal and plant, and by improving marketing systems. Very occasionally, we can improve the productivity of grassland systems by some kind of intervention on the grassland or forage itself. A lesson from mat, in general, is that in trying to apply the technologies of animal science to improve the systems we have to do it in a balanced way. Nosingl e technical intervention islikel y towor ko nit s own. The real challenge, therefore, is topu t our technologies together in an appropriate and well researched package sotha t the system canb eadapte d to themaximu m benefit of its owners ando f society in general, without losing thenecessar y scientific sharpness and definition. TheUniversit y ist ob ecomplimente d for selecting a subject that isbot h appropriate and timely. Prof. E.P. Cunningham Director Animal Production andHealt h Division F.A.O. 143 Rectal temperaturean dpuls erat eo fFriesia n andModican a cows inSicil y P.Giaccone ,A .Bonanno ,B .Portolan o

Istitutod i Zootecnica Gen.,Facolt àd iAgraria ,Universit é degliStudi ,Vial edell eScienze ,90128 ,Palerm o (Italy)

Summary The rectal temperature (RT) and pulse rate (PR) of Friesian cows, which have a great diffusion in Sicily, are studied with a view in evaluating their environmental adaptationt ohea to fclimati c conditions,i ncompariso n to thebehaviou ro fth eindigenou sModican a cows. RT and PR measurements were carried out on 314 Friesian and 600 Modicana cows, managed semi-intensively in the south-west of Sicily, aged 2-16 years, in different physiologic phases (late pregnancy, lactation, lactation and earlypregnancy) . The experiments extended during theJun ean d Julymonth s of 1987 and 1988. All observations were taken from 12.00 p.m. to 2.30 p.m. in open air conditions where the environmental temperature ranged from 30°C to 46.8°C and therelativ ehumidit y ranged from 18%t o65% . The Friesian cattle shows significatively higher values of the RT and PR than theModican a cattle (39.04 vs 38.75, 76v s 72respectively) , inal lphysiologi cphases . The effect of the physiologic phase is significant only for the RT, and the cows in late pregnancy record the highest averages inbot hbreeds . TheR T and PR result mainly inhig h correlations to the hours of themeasurement s taken, the relative humidity and the environmental temperature, always recording superior coefficients forth eFriesia nbreed . The RT of the Modicana breed is also significatively correlated toth eag ean dmonth so fpregnancy . The multiple regression, determined by the stepwise method, shows the highest coefficient of determination (R2=0.419)betwee nP R (Y),hour s (XjJ andrelativ ehumidit y (X2)fo rth eFriesia nbreed . Therefore the PR in Friesian cows appears mostly to be under the influence of climatic variations. In fact a more intensive increaseo fth ePR ,connecte dwit h the variations of the environmental temperature and the relative humidity can be noticed in the Friesian cows than in the Modicana cows. Soth eFriesia nbree d seemst ob enegativel y affected by environmental heat, but in any case the values of the considered physiologic parameters do not overcome the limitswhic h indicatea stat eo fphysica lstress . Extra descriptors: Friesian and Modicana cows; rectal temperature; pulse rate; environmental temperature; relativehumidity . 145 Bioclimaticparameter s andhemati cprofil e inMasses eewe s reared inTuscan y

A.Martini(l) ,P . Lupi(l),M.P .Ponzetta(2) ,A.Giorgetti(l ) (1)Dipartiment od iScienz e Zootecniche,vi adell eCascin e 5,5014 4 Firenze (2)Istitut oAgronomic ope r 1'Oltremare,vi aCocch i4 , 50135, Firenze

Summary 5 Massese ewes aged from 6 to 18 months were studied weekly by measurements of rectal temperature (RT), respiration rate (RR),puls e rate (PR).Measurement s were carried out at 8 a.m. . Air temperature in C° -(AT), relative humidity in % (RH),atmospheri c pressure in mbar (AP) were registered. Three-monthly the bioclimatic parameters were measured three times per day (8 a.m., 2 p.m., 6p.m. ) forthre eday s insuccession .Monthl y abloo d sample was collected. Benezra coefficient, as traditional expression (BC=RT/38.3+RR/23), as in modified expression (BC=RT/38.9+RR/33) where 38.9 and RR measured in Massese ewes in thermoneutral zone; Rhoad index [RI=100-10 (ART- 101.1)], where ART is the average of rectal temperature in F°betwee n thehotte r and the colderhou r of the day,wer e calculated. Bioclimatic parameters, hematic values and indices were analyzed by using two-way ANOVA (animal, season); differences between groups were tested by using "t" test. Residual correlations and regression between parameterswer eals ocalculated . All bioclimatic parameters and heat tolerance indices were influenced by season. The grater value of RR in hot season shows the importance of the respiratory evaporation in this species. AT influenced all bioclimatic parameters and the indices, giving rise to significant linear regressions, particularly with RR (y=28.2707+0.3503x) and PR (y=74.7564+0.3638); AP influenced RT, PR and RI; RH influenced PR and RI.R Twa s correlated to all bioclimatic parameters and indices. Hematic parameters changed significantlyamon gth eseasons ,eithe rbecaus eth eanimal s were growing, or because the feeding regime, composed of hay and barley, was modified to supply the nutritive requirements. Glycaemia was negatively correlated to RT (r=-0.388; d.f. 47),an d total proteins were negatively correlated toTR(r=0.319 ;d.f.47) .

146 Factorsaffectin greproductio no nth eone-humpe dcamels , Improvemento f reproductiveperformance s

P.Minoia ,G.H .Lacalandr aS H .Mosla h*

Istitutod iBiologi adell aRiproduzion ee dOstetrici adegl iAnimal !Dome - stici,Facolt àd iMedicin aVeterinaria ,universit éd iBari ,Italia ;* In ­ stitutde sRegion sArides ,Medenine ,Tunisie .

Dromedariesar eabl et oadap tthemselve st oextrem econdition so fli ­ fe,bette rtha nothe rlarg eanimals .Thi ssuperiorit yi srelate dt othei r highcapacit yt oresis tt owate rdeprivaion ,t otolerat eelevate dtempe ­ raturean dit sshar pchanges ,t oresis tt ohig hwate rsalinit yan dsal t plants,an dt osurviv efoo dshortage ,lo wprotei nlevels ,N an dP defi ­ ciency.Moreove rth ehig hpresenc eo fticks ,fly san dinterna lparasiti c agentsinterfere swit hmetabolism ,contribute st oenerg ydeprivatio nan d todetermin eba dreproductiv eperformance si.e. ,lon gcalvin gintervals , protractedpost-partu manoestrum ,irregula restru scycle ,abortion ,shor t breedingseason ,an dlo wlibid oi nth emal ecamel .Ou rexperienc ei nTu ­ nisiaallow su st oaffir mtha ti ti spossible ,wit ha preliminar ydiseas e andparasiti ccontro lan denerg ybalance ,t omanag ereproduction .Som ei n vestigationswer ecarrie dou ti ntw oconsecutiv eyear s (87/88-88/89)t o inducefertil eoestru swit hhormona ltreatment si nth eshe-camel sdurin g theno nbreedin gan dbreedin gseason .PMSG ,alon eo ri nassociatio nwit h progesterone (P ), (Minoiae tal .1991 )wa sinjecte di n15 7animals .Oe - 4 strus,matin gan dpregnanc yobtained ,reporte di nth efollowin gtable ,d e monstratetha ti ti spossibl et oinduc ereproductio ni nshe-camels ,eve n inseasona lanoestru sperio dan di nlactatin ganimals ,s oallowin ga nin ­ creasei nproductio nan da shortenin go fth eintercalvin ginterval .PMS G plusprogesteron etreatmen tgive sbette rresult stha nPMSG .

season 1987/88 1988/89

treatment PMSG PMSG+P PMSG PMSG+P 4 4 periods * ** * * **

n. camels 36 26 16 63 16

n.mate d 36 16 16 52 16 (%) (100) (61.5) (100) (82,5) (62,5) n. pregnant 24 9 13 34 5 (%)• (66,6) (56,2) (81,2) (65,3) (50) *non-breedingseason,"breedin g season;°%relatedt omate dcamels ;

MinoiaP. ,Mosla hM. ,Lacalandr aG.M. ,Corchan iM. ,Zarrill iA. :"Oestru s inductionan dmanagemen to freproductio ni nth efemal ecame l (cameldrom e darius").Accepte da tInternationa lCame lSymposyum ,Dubai ,Marc h1991 .

147 RABBITBREEDIN G INHO TCLIMATES:TH EUNDERGROUN D CELL SYSTEM*

P.Morer a &G . Kuzminsky Alternative Rabbit Breedings Experimental Centre Animal Husbandry Institute, Tuscia University, 01100 Viterbo, Italy.

High temperatures are a strong limiting factor to rabbit production intropica lan d subtropicalareas . When bred in cage, during hot season, the animal is exposed to the ambiental heat without any possibility to avoid it.Sinc eth ewell-bein g temperature for adultrabbit s ranges from 15 to 20°C, already at 25°C heat dissipation mechanisms begin to work, but over 30°C they tend to be exhausted. Physiological data are reported at this purpose and stress conditions of rabbits when temperature is about 35°C (R.H. 85%) are illustrated. The animals appear suffering and exhausted; posture and behaviour are modified to favour heat losses: body is stretched out, ears are laterally sidedan d snoutan dpaw sar ewet . Whenbreedin g environment ischaracterize d by longperiod s of stressing temperatures, water and feed intake, and both reproduction and production are severely affected to the point that, in the North-African countries, breeders completely stopmatin gth eanimal sfo rthre emonth so rmore . To avoid heat stress orth e limiting factor ofhig h costs of microambient conditioning which, anyway, cannot even be proposed in rural areas, an alternative breeding structure has been developed.The new breeding structures are described. They consist of single cells shielded by an embankment and connected each to an external cage by an appropriate pipe. In hot periods rabbit can behave like in nature, hiding in the underground fresher cell during the day and going out in the cool night hours to feed (ethological system). The underground cell, as the pipe, can be made of clay, concrete, bricks, stone or other local and cheapmaterials . The external cage can be made of wood, wire net or a combination of both. In this way building is abolished, cagesar ebrough tt oope nai ran dth econditionin g system is no longernecessar y (naturalambien t conditioning). Experimental and commercialunitie s in'North-Africaan d in Italy are shown. Efficiency of the underground cell system is illustrated through recording of physical data and biological efficiency is demonstrated on the base of bucks reproductiveperformances . Keywords:rabbit ,technology ,environment . * research supported byM.U.R.S.T .40% .

148 EFFECTO F SOLARRADIATIO NO NWATE RAN DFOO D INTAKEAN DWEIGH T GAIN IN "SARDA"AN D "COMISANA"FEMAL E LAMBS NardoneA. ,Ronch iB. ,Valentin iA . Istitutod i Zootecnia,Universit adell aTuscia ,Viterbo , Italy Introduction. It is known that the solar radiation has a geat influence on animal production. The aim of the present research was to evaluate the effect of the solar radiation in summertime on the water and food intake and theweigh t gain in a sample of twocommo n italianshee pbreeds . Material and methods. Twelve female "Sarda" lambs and twelve "Comisana"abou t9 month sol dwer eplace d in4 boxe sa sfollows :

6 SHEEPS 6 SHEEPS 6 SHEEPS 6 SHEEPS SARDA(Ssha) SARDA(Ssun) COMISANA(Csha) COMISANA(Csun)

SUN & PLAIN SUN SUN & PLAIN SUN SHADOW SHADOW

LW 28.7a ±1.6 28.0a ±1.8 32.7*> ±2.4 33.1*> ±3.7 MW 12.4a ±0.5 12.2a ±0.6 13.7° ±0.73 13.8b ±1.1 where LW = mean live weight, MW = mean metabolic weight. Different letters on a row represent a significant difference (P<0.05). The subjects in "sun&shadow" box were allowed to choose between shadowed or sunny areas, while those in "plain sun" were always exposed to sunshine.Th e trial lasted 10 weeks beginning from the 7th of July 1988. In this period we registered daily incollaboratio n with "Istituto diAgrotecnica , Universitédell a Tuscia",th emaximu m of ambient temperature and thetota l solarradiatio n (Fig.1). The animals were fed by Trendof ,som so fth e dirratic pargreters ad libitum hay and 200 regsteredddl y duringth etn d g/day/head of commercial T*C Radiationcd/c m feed (the latter always 600 completely eaten). We 50- i^fVv 500 registered the overall ^IWL water intake and 40- :400 individual liveweigh t at 30i ***2*ft«** r300 week intervals and oncea 20- -v**A 200 week a daily sample of V\-\ //- Vwv rv A >T^H hay ingestion. The 10- 100 animals did not suffer 0- IMMlllllinl I .1 Ii inn MiiTfHTnn il UMI ih nn i - sanitary problems. The 7/7 7/I4 7/2I 7/28 8/4 8/I8 8/25 9/1 9/15 data were analyzed by least sqare ANOVA by the — Tm'n -a- Tmax • TotdRadiatio n models:

(Water intake,DM/W)j^]C=M+breedi+Radji*breedi*sunshaj+Tmax^+e^j ^ Gainijjcl=M+breedi+Raaij*breedi*sun_snaj+TmaX]C+WeTghtOij]Cl+eij]Cl

149 where: Tmax and Rad are the weekly average respectively of the maximum ambient temperature and of the total solar radiation, sun_sha is the sun/shadow condition,DM/ W isth e hay dry matter eaten per Kg of live weight and WeightO is the live weight of thepreceedin gweek . Results.Th eestimate d leastsquar emean sare :

sunonl y sun&shadow water Gain DM/W water Gain DM/W 1/day g/week g/day 1/day g/week g/day comisana 3.38a 306 44.0b 2.64c 361 41.3a sarda 1.46b 278 46.2b 0.88d 296 41.8a

The regression coefficients (bjj of water and dry matter intake and weight gain with the average of maximum temper.atures (°C) (all the sample) and with the solar radiation (cal/cm") (by breed andkin d ofexposure )are : Water Gain DM/W ml/day g/week g/day Tmax 33.1 58.1 -0.13 Rad (Csha) -0.48 -11.7 -0.084 a** Rad (Csun) 0.42 -12.7 -0.068 ab** Rad (Ssha) -8.5 -0.074 ab** b** Rad (Ssun) 4.8* -9-7, -0.053 WeightO -94.6

bi*=P(bi=0)<0.05,b i **=P(bj=0)>0.01; bj3,bjb=P(bi=bj)<0. 00 5 *=P(bi=0)>0.05,**=P(bi=0)>0.01 ;

The increase of ambient temperature per se does not significantly affect the food and water intake, considering the overall sample. The "Sarda" sheeps significantly drink more as the solar radiation rises, while the weight gain is not depressed significantly.O nth eothe r hand the "Comisana" sheeps do not show a significant variation of water intake, but their weight gain is significantly reduced. The dry matter intake per Kg of liveweigh t is lower athig h levels of solarradiatio n for both breeds,bu tth e "Sarda"lamb ssho wth e lowerdepression . Discussion. The trial, though the limits of the sample, shows that the "Sarda" female lambs drink significantly less than the "Comisana" ones (1.46 vs 3.38 1/day if fully exposed to sun and 0.88 vs 2.64 in a shadowed ambient) and that, in the conditions of the trial and, for what concerns the weight gain, they are less affected by the solar radiation because when the radiation rises: i)the y significantly increaseth ewate r intake, ii)the y lower the food intake less than the "Comisana" lambs and iii) they do not significantly reduce the growth, as happens for the otherbreed .

150 Variability ofchemica lcompositio n andnutritiv evalu eo f somenatura l fodders inth evalle yo frive rBele s (Ethiopia) S.Pastorelli ,M .Orlandi ,L .Goio ,E .Meregalli ,G.B . Lipoli,F .Taccini ,R .Ranzani . Dipartimentod iScienz eAnatomiche ,Fisiologich e edell e ProduzioniAnimali ,Facolt àd iMedicin aVeterinaria ,2 , Vialedell ePiagge ,5610 0Pisa .

Summary The research was done inth eValle y of the riverBeles , a tributary of the Blue Nile, in the Goggiam region of Ethiopia. Three types of ground (called Black, Red and Brown)wer e each divided into two fenced areasmeasurin g 2 sqm, one in the shade and the other in the sun. In each area samples of the natural growthwer e cut 3time s during the rainy season. The 18 samples of natural growth were chemically analysed. Data were processed statistically and grouped according to soil type, time of cut and kind of cover. The differences between samples can all be imputed largely toth eparamete r "soil-type".I nfac t floragrowin g inth eRed-soi lyielde d thebes t levelso fcrud eProtei na s well as the lowest quantity of crude Fibre thus resulting the most digestible.Moreove r the Red-soil produced fodder withth ebes t levelso fenerg yvalu edu et oth ehig h levels of Nitrogen-Free Extract and Ether Extract. On the other hand, the Brown soil proved thewors t despite it being the most productive. Ityielde d the smallest quantity of crude Protein, N.F.E. and Ether Extract and the greatest of fibrous matter. In all areas the yeld in mineral elements were poor; Calcium resulting the most deficient. The same tendency was seen with Sodium whose concentration was insufficient to satisfy an animal's requirement especially intropica l conditions.Therefore ,a suitabl e supplementt o the natural flora would be necessary to insure adequate nutritive substances and mineral intake, especially in the Black and Brownsoils .

151