Development of Pigeon Feed for Commercial Squab Production in British Columbia
DEVELOPMENT OF PIGEON FEED FOR COMMERCIAL SQUAB PRODUCTION IN BRITISH COLUMBIA
BY
GWENITH A. WALDIE
B.Sc.(Agr.), University of British Columbia, 1982
A THESIS SUBMITTED IN PARTIAL FULFILLMENT OF
THE REQUIREMENTS OF THE DEGREE OF
MASTER OF SCIENCE
in
THE FACULTY OF GRADUATE STUDIES
(Department of Animal Science)
We accept, this thesis as conforming
to the required standard
THE UNIVERSITY OF BRITISH COLUMBIA 3 JULY 1986
(g^ GWENITH A. WALDIE, 1986 In presenting this thesis in partial fulfilment of the requirements for an advanced degree at the University of British Columbia. I agree that the Library shall make it freely available for reference and study. I further agree that permission for extensive copying of this thesis for scholarly purposes may be granted by the head of my department or by his or her representatives. It is understood that copying or publication of this thesis for financial gain shall not be allowed without my written permission.
Department of ftwiMAk Sci£Nc£
The University of British Columbia 1956 Main Mall Vancouver, Canada V6T 1Y3
DE-6 (3/81) ABSTRACT
Two experiments were conducted to evaluate the protein and energy requirements of squabbing pigeons.
The firBt experiment was carried out at a commercial farm, with birds housed in pens, each containing 10-12 pairs. Two pelleted feeds of different protein concentrations (low protein (LP) with l&V. CP and 2937 kcal ME/kg, and high protein (HP) with 22% CP and 2783
kcal ME/kg) were fed, with and without whole yellov
corn, cafeteria-style. A low protein intake was observed with LP + corn, which adversely affected squab
growth and livability, without affecting egg production
traits or adult body weight. HP without corn resulted
in a high protein intake with no effect on squab
production. The other two treatments (HP + corn and
LP) had intermediate protein intake while squab
production was unaffected. It was concluded that the
cafeteria feeding program (HP + corn) may be replaced
by a single pelleted ration, such as LP, without
adversely affecting squab production.
The second experiment was carried out at the new
UBC Pigeon Nutrition Unit, to determine the requirement
for, and utilization of, different fat sources by pigeons. Birds were housed in pair-cages and fed one of 5 pelleted rations, with 35 pairs per treatment.
The treatments consisted of a basal diet (with no added fat , 15% crude protein and 2650 kcal ME/kg) to which was added either sunflower oil (AT) at levels of 3V. or &'/.. Birds fed the basal diet produced no squabs, vhereas those on other treatments produced at least & squabs. Intake data from the first seven weeks of the trial indicated that pigeons eat to meet an energy requirement of approximately 235 kcal HE per pair per week when not producing squabs. Energy intake of those adults raising squabs vas highly variable and did not appear to correlate with squab production. The source of fat did not significantly v affect squab production. iii TABLE OF CONTENTS page ABSTRACT ii TABLE OF CONTENTS iv LIST OF TABLES vi LIST OF FIGURES vii LIST OF APPENDICES viii ACKNOWLEDGEMENTS ix I INTRODUCTION 1 II LITERATURE REVIEW 4 REPRODUCTION AND BREEDER MANAGEMENT IN PIGEONS 4 NUTRITION OF PIGEONS 9 A) Introduction 9 B) Factors Affecting Feed Intake By Pigeons 11 C) Proteins 14 D) Energy 17 i)Carbohydrates iiJFats E) Vitamins and Minerals 19 III EXPERIMENT ONE: EFFECT OF DIETARY PROTEIN LEVELS ON THE SQUAB PRODUCTION OF A PIGEON FLOCK IN A FLOOR PEN HOUSE, FED PELLETS WITH OR WITHOUT CORN, CAFETERIA-STYLE 28 Introduction 28 Materials and Methods 30 Results 36 Discussion 40 iv page IV EXPERIMENT TWO: EFFECT OF SOURCE AND CONCENTRATION OF DIETARY ENERGY ON THE SQUAB PRODUCTION OF A PIGEON FLOCK IN PAIR-CAGES 47 Introduction 47 Materials and Methods 49 Results 55 Discussion 70 V SUMMARY AND CONCLUSIONS 77 VI LITERATURE CITED 80 VII APPENDIX aa v LIST OF TABLES Table page 1. Composition of Diets fed in Experiment One 31 2. Effect of dietary treatment on feed and nutrient intakes, Experiment One 37 3. Treatment effects on body weights of growing squabs, Experiment One 38 4. Production traits of pigeons fed pellets of different protein levels,fed with or without corn, cafeteria-style, Experiment One 41 5. Effect of dietary treatment on initial and final adult body weights, Experiment One 42 6. Composition of Diets fed in Experiment Two 51 7. Effect of dietary energy source and concentration on feed and nutrient intake, Experiment Two 59 8. Effect of dietary fat source and Concen• tration on initial and final adult body weights, Experiment Two £1 9. Weekly body weights of growing squabs in Experiment Two 63 10. Comparison of body weights of squabs raised as one- versus two-squab nests, Experiment Two 65 11. Effect of dietary energy source and concentration on pigeon production traits, Experiment Two 69 12. Effect of mode of incubation (natural or artificial) on squab production, Experiment Two 71 vi LIST OF FIGURES Figure Page> 1. Effect of dietary treatments on body weights of growing squabs, Experiment One 39 2. Feed intake of pigeons on Experiment Two 56 3. Metabolizable enery intake of pigeons on Experiment Two 57 4. Crude Protein intake of pigeons on Experiment Two 58 5. Egg Production, Experiment Two 68 vii LIST OF APPENDICES Appendix page 1. Squab mortality in Experiment One 88 2. Number of Squabs Hatched over Time, Experiment Two 89 3. Identification of squabs produced in Experiment Two 90 viii ACKNOWLEDGEMENTS I am indebted to my thesis advisor. Dr. J. S. Sim, for providing valuable guidance and assistance throughout the course of my graduate program. Sincere thanks are also due to the other members of my advisory committee: Dr. K. M. Cheng, Dr. R. C. Fitzsimmons, and Professor B. E. March, for their helpful criticisms of the preliminary draft of this thesis and for their valuable advice during my program. My gratitude is also extended to the many who have helped me, particularly the management of Vancouver Island Mountain Squab Farm, Andrew R. Hickman, Mark Newcombe, Dr. R. I. McKay, and the graduate students and laboratory communities of both Animal Science and Poultry Science. I am grateful to the B.C. Science Council for supporting my research with a G.R.E.A.T. award, and to the Jacob Biely Memorial Scholarship Committee for choosing me as the recipient of this award in 1985. ix INTRODUCTION: The pigeon has been used as a meat-producing species around the world for centuries. Traditionally, pigeon producers and breeders have fed their birds a mixture of available local grains and a health grit (see page 26). As in any livestock industry, balanced feed is a basic requirement for efficient production. Unfortunately, thex-e is only limited information available on the dietary requirements for specific nutrients or on experimentally-proven balanced feed formulas for pigeons. Much research has been directed towards defining what constitutes a well-balanced ration under various developmental and physiological conditions of chickens and turkeys. It is only recently that research efforts have been directed to other game birds such as quail, ducks, geese, pheasant and guinea fowl, and such information is not yet available for squabbing pigeons. Pigeons differ from other poultry in that their mating and brooding system (pair-bond formation and the dependence of young on the parents) requires the maintenance of a parent flock (referred to as "breeders"). The breeder flock consists of pairs, each of which produces approximately 12-15 squabs per year. A squab is a young pigeon, marketed at 28-35 days of age, weighing approximately 550-600 grams. 1 For the first 5 to 7 days of life, the altricial squabs are fed exclusively on a secretions of the crop of the adults called "crop milk". A squab-producing industry has existed in North America since the early 1900's (Levi, 1974). In the United States, annual production is over one million squab (Cheng, 1986). This figure represents 1% of the world production of squab. In Europe, annual consumption is in the millions, with France and Italy comprising the major market. Southeast Asian countries are heavy consumers of pigeons. In Hong Kong, annual consumption is approximately 5.5 million, (an average of one per capita >. The projected demand for squabs in Canada is estimated to be 500,000 per year (Marketing Research, Vancouver Island Mountain Squab Farm, 1983). The ethnic communities of Chinese, French and Italians comprise the projected market. The Chinese community in Vancouver, numbering around 200,000, currently represent 80% of the Vancouver market and it is estimated that this community will consume 200,000 squabs (an average of one squab per capita.) Hence a healthy local market is assured. The local product has a marketing advantage over the imported product, as it can be prepared "New York 3 dressed", which the Chinese prefer. Vancouver Island Mountain Squab Farm (V.I.M.) and another contract distributor in Quebec have been importing about 120,000 squabs per year from the U.S.A. since 1982 (Cheng, 1986). This is indicative of a healthy nation-wide market. V.I.M., located in Lantzville, B.C., has a capacity for 10,000 pairs of pigeons, which translates into a possible annual production of 120,000 to 150,000 squabs for the local market. V.I.M has been collaborating with the U.B.C. Department of Poultry Science since 1982 to develop a feeding program for its breeding flock. The following thesis reports the results of this project, aimed at advancing the knowledge of nutrition of commercial squabbing pigeons in B.C., so that the results can be directly applied to the industry. This study was specifically intended to examine the protein and energy requirements of squabbing pigeons, initially by comparing two feeds and two feeding systems; and then, by examining the role of supplemental fat in rations of squabbing pigeons. 4 LITERATURE REVIEW Reproduction and Breeder Management in Pigeons Pigeons are unique in several ways when compared to other domestic birds such as chickens, turkeys, geese and ducks. Firstly, unlike the domestic fowl mentioned above, whose young can be hatched in incubators and, at hatch, are relatively self-sufficient (precocial), young pigeons are totally helpless (altricial) and must be raised by the parents. Secondly, adult pigeons pair-bond for life, with both parents incubating the eggs and brooding the young. Finally, the most important--and confounding-- characteristic that sets pigeons apart from other domestic fowl is that the parents produce "crop milk" for their young and this crop milk is produced in equal quantities by male and female (Dumont, 1965). In birds, this characteristic is unique to pigeons and doves (Class Aves, order columbiforme) (Dumont, 1965) and the cock pigeon or dove is the only male vertebrate that produces a "milk" for its young (Levi,1974). Crop milk is an oily, yellowish, cheese-like substance. It consists of lipid-laden cells that are exfoliated from the epithelial lining of the lateral lobes of the crop (Dumont, 1965). Crop milk is exclusively utilized for the nourishment of the progeny, and its production is controlled by the anterior pituitary hormone, prolactin (Riddle and Braucher, 1931; cited in Dumont, 1965). Much work has been done on crop milk, particularly in terms of its production, its composition and its response to prolactin (Patel, 1936; Beams and Meyer, 1939; Davies, 1939; Leash et al., 1971; Hegde, 1972a; Hegde, 1972b; deLima, 1978; Desmeth, 1980; Desmeth and Vandeputte-Poma, 1980; Vandeputte-Poma, 1980; and Silver, 1984). These three factors combine to complicate the feed management of squabbing pigeons. On a pair scale, the situation is one of feeding two birds (one of which is producing approximately 2 eggs per month) which both produce, on occasion, food for the young. On a flock scale, all of this is happening at different times and rates, unique for every pair. A pigeon is sexually mature at 6 months of age (Levi, 1968). No sexual dimorphism occurs in pigeons. A clutch consists of two eggs, which both parents incubate. The male usually tends the nest from about 10:00 a.m. to 4:00 p.m., and the female takes over the rest of the time (Nohlgren and Wagner, 1977; Clarkson 6 et al., 1963). If the setter is removed from the nest, its mate will take over the hovering (Nohlgren and Wagner, 1977). Should one mate die or be removed before the eggs hatch, its mate will incubate for a day or longer before abandoning the eggs (Levi, 1974). If squabs are in the nest, the remaining parent will care for it singly (Liebman et al., 1970). Birds will incubate inappropriate objects such as a lump of manure. For this reason, the nest should be checked regularly, both for soundness and actual presence of eggs. If the eggs are removed from the nest or if the pair abandons them, the female will lay another clutch, in as early as 15 days (Waldie, unpublished observations). This is the basis of "pumping", the practise of taking eggs from certain pairs and adding them to clutches of other pairs at the same stage of incubation. This way, females of pairs whose eggs have been taken will commence to lay another clutch much faster than if they were allowed to incubate the eggs and raise the young. "Pumping" can more than double the production of eggs, by halving the laying interval. Hatchability is not affected (Waldie, unpublished data). After 17-18 days of incubation, the squabs hatch. They are immediately fed crop milk regurgitated by the parents. Crop milk is responsible for the remarkable growth rate of squabs. A newly-hatched pigeon weighs 15 grams. A day-old pigeon weighs twice that; three days after hatching, the squab is adding 39,'/. of its weight daily and at 11 days, the rate is still 14% (Riddle et al, 1932). Yanni (1969) observed that at the end of the brooding period the body weight of growing pigeon was on average 35 times its hatching weight. In contrast, the body weight of a chicken at 4 weeks old was on average 6.97 times its hatching weight. Crop milk is about 15% crude protein on a wet basis (50% on a dry basis). Its fat content is also high, being about 10-12% (wet weight basis) and 25-29% (dry matter basis). In contrast, a chick starter diet contains 20% crude protein and 5-6% fat. In their first few days of life, squab are fed entirely on crop milk regurgitated by the adults. After this time, the crop milk is increasingly mixed with grains or pellets soaked in the crops of the parents until about 7-9 days after hatch (Leash et al. , 1971), when crop milk production ceases. Vandeputte-Poma (I960) reported that all pigeon parents produce crop milk until Day 12, and that 16% of his flock produced a it until Day 25. The amount of feed actually ingested by the squab (regurgitated by the parent) is hard to determine, however there is very little wastage. The squabs' eyes open at 3-4 days of age. After seven to ten days, the adults no longer sit directly on the squab, but remain in close proximity unless the temperature is low (Riddle et al., 1932; Levi, 1974; Wortis, 1969). When the squabs in one nest are about 2-3 weeks old (Lee and Haynes, 1942), the adults begin the courtship and nest-building routine again, and the female will lay two more eggs. Once this new clutch is laid, the parents divide their time between incubating the new eggs and feeding the squab. For this reason, pigeon housing requires two nest-boxes per pair, usually side- by-side with an attached perch. Pigeons are territorial (Nohlgren and Wagner, 1977) and once they've chosen a nest site, will rarely move unless forced out by another pair. The lifespan of pigeons can be over 20 years (Levi, 1974), however, the productive life is much shorter than this. Most of the literature recommends culling at 5-6 years. Males tend to live longer than 9 females (Levi, 1968; Burley and Moran, 1979). Pigeons are capable of producing 22 squab per year in the case of the White Carneau breed (Clarkson et al., 1963). However, 15 squab per pair per year is "good" and anything above that, "excellent". Most squab producers cull at 12 squabs per pair per year (Levi, 1968.). Peak production occurs during the late spring to early fall. The birds usually moult in September and October, and pairs that continue to produce through the moult and feed their squab successfully should be earmarked as replacement breeders, as squab fetch the highest price at this time when squab supply is reduced. Nutrition of Pigeons A) Introduction Despite the fact that pigeons are extensively used as experimental models in studies of atherosclerosis (Nohlgren and Wagner, 1977; Cramer and Smith, 1976; Clarkson et al., 1963), vitamins (Clarkson et al., 1963), reproductive physiology (Riddle, 1947), psychology (Skinner, 1950, 1951; cited in Hollander, 1954), and genetics (Hollander, 1954), very little is known about their nutritional requirements. 10 Pigeons are granivorous (Abs, 1983) and pigeon producers have traditionally fed their flocks a mixture of locally-available grains plus a health grit. Each producer has a mixture that he is convinced is the best (Levi, 1968), but no scientifically-proven feed formulas or dietary requirements for specific nutrients are available in the literature. Perhaps this has to do with the complicated animal model that pigeons present, inherent with their crop-milk and pair-bond mating system. The science of nutrition integrates knowledge of biochemistry and physiology of an organism, encompassing the ingestion, digestion, absorption, and utilization of chemical elements which serve as its food. Specific nutrients (energy, amino acids, vitamins, minerals and water) are needed in order to meet the animals' requirements for: 1. Body maintenance--keeping all organs and tissues functioning; 2. Growth—building and depositing muscle, feathers, bone and other tissue; 3. Reproduction—egg production and care of the young; and 4. Flight--muscle use. 11 These nutrients must be optimally balanced both within and between nutrient classes in order to maintain performance. In commercial pigeon production, besides meeting the nutritional needs of the birds and consumer demands for a desirable product (in this geographic area, a white-skinned, tender, yellow-fatted squab is preferred), the producer has a few criteria of his own, directed at the parent flock and their maintenance. These include: 1. Least-cost formulation of the diet; 2. Prevention of excess fat deposition in the adult birds; 3. Ensuring the palatability of the feed, to minimize wastage. Feed costs are estimated to be 60% of a farmer's costs. Maximizing efficiency of feed usage will cut these costs. B) Factors Affecting Feed Intake by Pigeons Pigeons are granivorous, although feral pigeons and wild Rock Doves have been reported to eat animal matter, in the form of small snails and earthworm cocoons (Murton and Westwood, 1966). These authors 12 note that these animal materials appear throughout the year in the diets of those birds studied. Hollander (1954) suggests that the snails are eaten as a source of lime. Pigeons do not require green food. Ward and Cryer (1981) reported that the provision of fresh vegetable material was discontinued after a period of 2 months when it became obvious that the pigeons did not eat any of it. For some reason, freshly harvested grain which has not been aged and dried can make pigeons violently ill. The squabs succumb within one day, followed several days later by the adults, both old and young developing severe watery diarrhea (Giammettei, 1976). Pigeons will not eat a mash diet. They require either a whole grain mixture or pellets (Jull, 1947; Hollander, 1954). No studies are available examining the preferred size of feed. The ceca of pigeons are so small that they are considered to have no use (Levi, 1974; Abs, 1983). A high fiber diet is not tolerated well by pigeons. Several authors (Jull, 1947; Heuser, 1955; Levi, 1974; Giammettei, 1976) recommend a dietary crude fiber level of less than 5%. Pigeons do little or no feeding at night (Normile 13 and Barraco, 1971; Zeigler et al., 1971; Pietras and Wenzel, 1974). Food preferences of wild and domesticated pigeons are strongly influenced by availability (Levi, 1974; Abs, 1983). Although pigeons seem to be able to live and raise squab on very limited food resources (Abs, 1983), some production parameters are affected (Piatt, 1939). Laboratory pigeons exhibit stable idiosyncratic feeding behaviours. Moon and Zeigler (1979) reported that pigeons offered a choice among several types of seed presented separately in substantial quantities, show individual patterns of seed selection behaviour which persist over prolonged periods. They concluded that since food selection is under control of its nutritive and metabolic consequences, both short and long term reinforcement processes play an important role in maintaining feeding behaviour on specific foods. Hollander (1954) implies that breeding pigeons will choose a higher protein ration than non-breeding birds. Moon and Zeigler (1979) reported that pigeons shifted their idiosyncratic seed selection patterns to maintain body weight after surgical trigeminal nerve 14 deafferentation. This surgery disrupts the sensory control of the feeding response such that pigeons have difficulty in grasping or mandibulating individual grains. Eating small seed was less efficient than eating larger grains, and the birds' feeding patterns consistently shifted to the larger seeds and grains. C) Protein The requirement for proteins is more precisely a need for amino acids. Husbandry books on pigeon production (Lee and Haynes, 1942; Jull, 1947, Heuser, 1955; Ewing, 1963; Giammettei, 1976) recommend 13-15'/. crude protein, with the majority of references citing rations based on corn, wheat, milo, and peas. Ewing (1963) provides a pelleted pigeon reference ration However, he does not provide details of production of birds maintained on this diet. In the research carried out using pigeons in areas other than nutrition, the following has been noted regarding protein nutriture. Little and Angell (1977), looking at an interaction between dietary protein level and experimentally-induced aortic atherosclerosis in White Carneaux pigeons, reported that a 10% crude protein diet (based on 15 purified ingredients), with 10% corn oil, was insufficient to maintain pigeons, but that 20% and 40% crude protein diets did not result in a significant body weight change, although both groups lost net weight (8.2 and 34.4 grams, respectively). Intake data was not recorded and the energy content was fairly high (10% corn oil); therefore, it is possible the pigeons were eating very small amounts of the 20% and 40% crude protein diets. These birds were not being maintained for production. Suguira and Benedict (1923) studied the adequacy of certain synthetic diets for the nutrition of pigeons. They found that daily rations of 15-20 grams of synthetic diets containing 22% casein, 10% cane sugar, 27% starch, 2% agar-agar, 3% salt mixture, 30% butterfat, and 6% yeast or of 22% casein, 10% cane sugar, 37% starch, 2% agar-agar, 3% salt mixture, 6% yeast and 20% lard were adequate for egg production, growth and maintenace in common pigeons. McNabb et al.(1972), studying the effects of dietary protein content on water requirements and ammonia excretion in pigeons, fed pigeons daily a ration of either wheat (Low Protein=ll% crude protein) or soybean meal (High Protein=44% crude protein). They reported lower final body weights for those birds fed the high protein diets (for all regimens of water intake) and related that lower body weight of pigeons adapted to high protein diets may be beneficial in reducing the overall metabolism of each individual. However, they did not address feed intake and palatability, nor did they note that restricting water intake would cause a decreased feed intake, which in turn would cause a decreased body weight. Carr and James (1931) looked at the growth rate of squabs whose parents were fed different grains (hemp, kaffir, corn, wheat, soybeans, and hulled oats). They noted that the growth rate of squab fed on single grains and minerals was less rapid than that of those fed a mixed grain diet, although the squab continued to increase weight constantly in the pre-weaning period. The feeding of a single grain plus minerals resulted in great variations in squab weight, with one squab in a two-squab clutch sometimes weighing twice as much as the other at the end of 3 to 4 weeks. In this study,the squabs whose parents were fed hemp seed made good gains before and after weaning, and the researchers reported it as being well-balanced. 17 The corn-fed squab made slow progre ss while being fed crop-milk; they grew very slowly ai ter weaning. Abs (1983) noted that there is no reason to believe that pigeons do not require the san e essential amino acids as do chickens and turkeys, e specially considering that the pattern of 7 e ssential amino acids in pigeon milk is similar to that c if the amino acids required for growth by chickens. Wolter et al. (1970; cited in Abs, 1983) reported that voluntary intake of feed puts the requirement for protein at 12.5 to 13% of the diet. D) Energy 1) Carbohydrates It is generally recommended in husbandry books that a pigeon diet should contain 60-70% carbohydrate. (Heuser, 1955; Giammettei, 1976). Considering that pigeons are granivorous, with grain contributing the greater part of their normal diet, carbohydrates are likely their main source of energy. It is interesting to note, however, that pure pigeon crop milk contains no carbohydrate except by contamination with the adult's food (Davies, 1939; Leash et al., 1971). Ewing's reference pigeon ration (1963) contains 60% carbohydrate. la Many studies of carbohydrate metabolism in the pigeon have been conducted (see Levi, 1974). Riddle et al. (1932) found that the young squab (3 days after hatching) burns little or no carbohydrate and has a metabolism not much higher than that of a fasting pigeon 89-146 days after hatching. ii) Fats and Lipids Although pigeons gain most of their energy from the starch in the grain they consume, fats and proteins can and do satisfy part of the energy requirement. Recall that for its first few days of life, the squab is fed on high-fat crop milk (Abs, 1983). March et al. (1978) report elevated levels of free fatty acids in the blood of band-tailed pigeons during incubation and crop milk production, possibly reflecting the increased demand for energy during this time. Goodman and Griminger (1969) reported that racing pigeons fed diets supplemented with fat out-performed those birds fed diets without supplemental fat. The longer the race, the greater the improvement in performance, leading the researchers to conclude that for sustained flight, pigeons may be able to utilize fat better than dietary carbohydrate as an energy source. Heuser (1955), Levi (1974), and Giammettei (1976) all recommend a range of 2-5% crude fat in a squabbing pigeon ration. However, these authors advocate whole grain rations which may preclude the use of supplemental fat. Ewing (1963), in his reference pigeon ration, did not use supplementary fat. The label on Purina Pigeon Chow does not list added fat. Suguira and Benedict (1923) reported that an adequate food for pigeons would contain about 70 calories gross energy in the daily ration. E) Vitamins and Minerals Pigeons have been used in research since the first vitamin studies in which, in 1897, Dr. C.C. Eijkman, discovered that he could speedily cause beri-beri (polyneuritis) in pigeons and chickens by feeding them only polished rice. Levi (1974) reviewed early vitamin work using pigeons. Vitamins are classified as either fat-soluble (Vitamins A, D, E, and K) or water soluble (the vitamin B complex and Vitamin C). Thirteen vitamins are considered essential to pigeons (all but Vitamin C, which can apparently be synthesized by the bird). Vitamin A: This vitamin is most available to 20 pigeons as its precursor, B-carotene, in yellow corn, peas of all kinds, and in green leaves and alfalfa meal. Althought Vitamin A is essential in nutrition, the amount required by pigeons is uncertain, and scientific opinion is that it is quite small or very efficiently stored in the liver (Levi, 1974). Although Suguira and Benedict (1923) reported that pigeons required no Vitamin A, this has been repeatedly refuted. Emmett and Peacock (1923) reported that pigeons appeared to require less Vitamin A than other birds; and Abderhalden and Wertheimer (1923; cited in Levi, 1974) reported symptoms of xeropthalmia and keratinization of the kidney in pigeons fed Vitamin A- deficient diets. Waters (1952) demonstrated that pigeons apparently require less Vitamin A than rabbits via an experiment in which he fed three squabs a diet that had produced Vitamin A deficiency symptoms in rabbits within 6 months. The pigeons showed no symptoms until 17 months, at which time they displayed weight loss, dryness and scaliness of the face and "scum" in the corners of the eyes. Two birds died at 18 months and the third recovered after administration of Vitamin A. The addition of carotene-containing components 21 (for example, peas and alfalfa meal) to the diet of pigeons confounds the requirement for Vitamin A, as reported by Shultz et al. (1953). They reported that when the diet contained green peas, the vitamin supplement containing vitamins A and D had no effect. A recent article claims that Vitamin A deficiencies frequently occur in pigeons and are in fact more prevalent than ever suspected (Tudor, 1982). Although giving no information on the background of the pigeons, he reported the symptoms (small white pustules in the larynx and tonsillar area of the soft palate) responded favourably to addition of 10,000 IU per pound of feed of stabilized Vitamin A formulation for the first 1-2 weeks of treatment, followed by 2,000 to 4,000 IU per pound of feed on a maintenance basis. Vitamin E: Vitamin E has two important metabolic roles, as an antioxidant and as a cofactor in selenium metabolism. An animal's physiological status of Vitamin E and, hence, its requirement for Vitamin E depends on the following: a) the amount of Vitamin E (tocopherol) being consumed, b) the level of pro- oxidants and antioxidants in the diet, c) the level of of selenium in the diet, and d) the dietary intake of sulfur amino acids (Martin et al., 1983). A deficiency 22 of Vitamin E can cause decreased hatchability of pigeon eggs, resulting in lower production (Giammettei, 1976). Vitamin D3 t There is disagreement regarding the requirement of the pigeon for this vitamin. Shultz et al. (1953) reported that a supplement of Vitamins A and D3 had no effect on squab production, because the birds were exposed to sunlight. Hollander and Riddle (1945; cited in Levi, 1974), observed that a deficiency of Vitamin D in the diet and lack of sunlight was associated with rickets in squabs and softening of the bones in the breeding female. Vitamin K: Vitamin K is necessary for the formation of prothrombin and the regulation of synthesis of other clotting factors. It is synthesized by bacteria in the large intestine and is widely distributed in green leafy vegetables, alfalfa being one that is commonly incorporated into pigeon diets. There is little storage of this vitamin in the body, other than in the liver. Fowl appear to be the domestic animal most susceptible to Vitamin K deficiency, possibly due to short intestinal tract (Lloyd et al., 1976). Absence of a dietary source of this vitamin leads to subcutaneous and intramuscular hemmorhage in birds (Lloyd et al., 1976). 23 Among bird, different species have different needs: chicks, ducklings and goslings require Vitamin K, whereas pigeons and canaries are much less susceptible to a Vitamin K deficiency (Lloyd et al., 1976). Dam et al, (1937; cited in Levi, 1974) showed that pigeons do develop hemmorrhages on Vitamin K deficient diets. Ralston-Purina adds Vitamin K to their commercial pigeon chow and Ewing (1963) included it in his pigeon reference ration at the level of 2 grams menadione soduim bisulfite complex (MSBC) per ton, in addition to 400 mg MSBC per pound in the premix. Vitamin B Complex: The members of the B-vitamin family function primarily as cofactors in enzyme systems. Pigeons figured prominently in early Vitamin B studies: R.R. Williams privately searched for the antineuritic factor by experimenting at home with pigeons housed in his garage. He discovered thiamine in 1935 (Lloyd et al., 1976). In 1939, McHenry and Gavin studied the effect of thiamine on the synthesis of body fat in pigeons and reported that 60 micrograms of thiamine daily in addition to ad. libitum rice diet prevented polyneuritis. Carter and O'Brien (1939a, 24 1939b) reported that pigeons required at least two aqueous soluble factors of liver and yeast in addition to aneurin (thiamine) and riboflavin. These two additional factors they called Vitamin B5 and Vitamin B3, now known as niacin and pantothenic acid. Harris (1939) reported that nicotinic acid is required by pigeons. In more recent years (Lofland et al. , 1963; Itokawa, 1975), pigeons have continued to be used in thiamine-deficiency and -interaction studies since pigeons are considered to be one of the most sensitive species to thiamine deficiency (Itokawa, 1975). Pigeon meat can be considered a rich source of thaimin when compared with chicken, beef, and rabbit (El-Sayed, 1980). It is also an excellent source of riboflavin. Shultz et al. (1953), in a squab production trial reported that supplementation of grain and pea-based diet with riboflavin increased squab number significantly. Vitamin Bt a appears to have a benefici effect on squab number although it was not statistical significant. The group fed supplemented riboflavin an Vitamin Bia displayed increased hatchability. The riboflavin increased liveability but the Vitamin Bia did not. 25 Pigeons practise coprophagy, a potentially important source of Vitamin Bta (cyanocobalamin) (Giammettei, 1976). Peeters et al. (1977) reported an incidence of pyridoxine (Vitamin Bs) poisoning in homing pigeons after administration of a human vitamin preparation. The toxic compound was identified as pyridoxine hydrochloride, the lethal dose being 90-100 mg (equivalent to about 200 mg per kilogram of body weight). Up to three times this dose rate had no effect on chicks. Hegde (1973) reported the following vitamin values for crop milk: Vitamin A, trace; thiamine, none; riboflavin, 181.26 ug/lOOg; ascorbic acid, trace. Reed et al. (1932) fed crop milk to rats as a supplement to to a Vitamins A- and B-deficient diets, and concluded that the liberal supplies of vitamins received by the squab through the daily ingestion of crop milk likely contribute to the very rapid growth exhibited by these birds. Guareschi (1936; cited in Pace et al. , 1952) fed squabs an artificial diet high in protein, fat and vitamin B and found that they did poorly on it. Vitamin C: Pigeons do not require a source of dietary Vitamin C, as they are apparently able to 26 synthesize this vitamin (Levi, 1974; Giammettei, 1976; Whiteacre, pers. comm.). Minerals: Pigeons, as compared to mammals and poultry, seem to require far greater amounts of minerals (Levi, 1974). Mineral "health grits" are generally made available to pigeons; these grits contain such components as limestone or granite grit, oystershell, charcoal, bonemeal, salt and what Piatt (1951) referred to as tonics: anise seed, gentian seed, sulfur and Venetian red. This researcher examined the relative necessity of these items to pigeons. After 18 months of feeding pigeons various combinations of these compounds, he reported that a mixture containing 85% oystershell, 10% hardwood charcoal, and 5% salt was adequate to meet the requirements of squabbing pigeons. Pigeons have a requirement for iodine to prevent goiter (Hollander and Riddle, 1946; Hollander, 1954; and Ewing, 1963), a condition that may be augmented by a high fat content in the ration. Patrick and Schaible (1980) indicate a relationship between the secretion of pigeon milk and an iodine requirement, however, they do not elaborate. Calcium and phosphorus are required for egg 27 production (Jull, 1947). Calcium, phosphorus, sodium, potassium, magnesium, chlorine, iodine, iron, manganese, copper, molybdenum, zinc, and selenium are all required by pigeons (Whiteacre, pers. comm.) Purina Pigeon Chow contains the following levels of minerals (expressed as '/. of dry matter): P, . 64 - .84; Na, .126 - .139; Cl, .134 - .145; K, .717 - .813; Mg, .191; Ca, 2.18 (Leash et al., 1971). EXPERIMENT ONE EFFECT OF DIETARY PROTEIN LEVELS ON THE SQUAB PRODUCTION OF A PIGEON FLOCK IN A FLOOR PEN HOUSE FED PELLETS WITH OR WITHOUT CORN, CAFETERIA-STYLE Introduction: In 1983, a project was initiated in a commercial farm environment to evaluate existing feed and feeding programs. The findings of this experiment (Waldie et al., 1984) showed that the pelleted complete diets were superior to the whole grain diet in supporting commercial squab production. The results also suggested that the locally-milled diets were as competent as the commercial complete pelleted diet in supporting squab production. Finally, it was reported that birds on the corn supplemented, high protein pellet had best performance. Cafeteria feeding allows the birds to choose their own diet. However, due to the high cost of corn in Western Canada and the manpower required to keep corn available to the birds, the following experiment was 28 29 initiated. The objectives of this study were a) to determine the protein requirements of squabbing pigeons in a commercial environment, and b) to determine whether the cafeteria-style feeding program had any advantage over a complete pelleted diet. This was proposed through an experiment in which two pelleted rations of differing protein levels were fed, both with and without corn, cafeteria style. 30 Materials and Methods: One hundred and thirty-six pairs of White King and Silver King pigeons were selected from the breeding flock at VIM. Pairs were identified by colored leg bands. The males were approximately 2 years old and the females were of undetermined age. These birds were randomly distributed among 12 pens (dimensions 1.7 x 1.8 x 2.5 m), 10 to 12 pairs to a pen. Each pen contained 12 nesting units. Water was provided from an automatic watering cup. Feed was supplied in a wooden, self-feeding trough. Feed and water were supplied ad libitum, as was a granite grit. Birds were maintained on a diet of corn and high protein pellets prior to the start of the experiment. During this time, the pigeons were allowed to produce squab. 14 hours of light <14L:10D) was maintained. Two pelleted diets were evaluated. (See Table 1 for formulations of the experimental diets.) The Low Protein (LP) pellet was formulated at the University of British Columbia, and contained !&'/. crude protein and 2937 kcal ME/kg. It contained autoclaved eggshell waste as a source of calcium and vegetable oil as a source of energy. The mineral and vitamin premixes were made up at UBC, transported to Nanaimo along 31 Table 1. Composition of Diets fed in Experiment One Ingredients percentage in diet Low Protein Pellet Ground Corn 60. 0 Soybean Meal 16. 0 Wheat Middlings 12. 0 Alfalfa Meal 3. 5 Vegetable Oil 3. 5 Bone Meal 2. 0 Eggshell Waste 1. 5 Vitamin Mineral Premix #1° 1. 0 Dicalcium Phosphate 0. 5 High Protein Pellet Ground Corn 26. 5 Soybean Meal 24. 5 Wheat 20. 7 Ground Barley 15. 0 Canola Meal 5. 0 Meat and Bone Meal (50*/.) 2. 9 Alfalfa Meal 1. 2 Limestone 0. 6 Tallow 0. 5 Vitamin Mineral Premix #2 0. 5 Salt 0. 1 Calculated analysis: Low Protein Pellet: Protein 16.0, M.E. 2937 kcal/kg, Ca 1.4%, P 73%. High Protein Pellet: Protein 21.7%, M.E. 2783 kcal/kg, Ca .63%, P .54%. "Premix #1 contains per kilogram*. Vitamin A 8810 IU, Vitamin D3 881 ICU, Vitamin E 30 IU, Vitamin Bia 13.2 ug, Riboflavin 6.6 mg, Calcium pantothenate 8.8 mg, Niacin 22 mg, choline chloride 440 mg, methionine 1.5 grams, 75% MnS04-xH30 410mg, ZnO 45.6 mg, Iodized salt, 5. Og. 32 with the autoclaved eggshell waste, and stored there until the diet was mixed and pelleted at Nanaimo Farmer's Co-op. The High Protein (HP) pellet was a ration formulated and mixed for Vancouver Island Mountain Squab by the Nanaimo Farmer's Co-op, and was VIM's breeder diet, fed with corn. The crude protein level was 22% and the ME level was 2783 kcal/kg. It contained limestone as a source of calcium and animal tallow as a supplemental fat source. Three pens (a total of 34 pairs per treatment) were assigned to each of 4 experimental treatments, in a 2 x 2 factorial design. The four treatments were as follows: LP -- Low Protein Pigeon pellets LPC -- Low Protein Pigeon pellets plus corn HP -- High Protein Pigeon pellets HPC -- High Protein Pigeon pellets plus corn All diets were available ad libitum. LPC and HPC were afforded corn and pellets in side-by-side feeders, cafeteria style. Water and granite grit were provided ad libitum. At the same time every week, feed consumption was determined by difference (by weighing back the feed not 33 eaten). Feed intake of pellet plus corn diets was the sum of the two components. Male and female adult body weights were recorded at the start and end of the experimental period. Nests were checked daily for production of eggs, egg breakage, and presence of squabs. Since pigeons are territorial, each nest-site generally represented one pair. From the daily nest checks, the following parameters were calculated: Egg Production = total number of eggs laid. Fertility of Eggs = number of fertile eggs / number of eggs laid minus number of eggs cracked and missing. Hatchability of Fertile Eggs = number hatched / number laid minus number cracked and missing minus number infertile. Squab Mortality = number of squabs that died before 4 weeks of age. Squab hatch dates were recorded, and at 1-week intervals, the squabs were weighed (1, 2, 3, and 4 weeks of age). Kilograms of squab produced per pen was calculated as number of squabs hatched times average squab weight. Mortality of adults was monitored. When an adult died, its mate was removed and another producing pair added to the pen. 34 Experimental period wa s nine weeks. Statistics: Egg produ ction parameter (production, fertility, and hatchability ), percent squab mortality, and percent adult mortality were subjected to arcsine transformation according to Zar (1984) and then to a one-way analysis of varianc e (PROC ANOVA), using Statistical Analysis System (SAS, 1985). Number of squabs per treatment and ki lograms of squab per treatment were subjected to a one-way ANOVA (SAS,1985). Body weights of squab at ea ch week of the 28-day growth cycle were analyzed by one-way ANOVA (PROC GLM) using SAS. Initial and final adult body weights of male and female pigeons w ere subjected to a two-way ANOVA, using SAS, with sex an d treatment as main effects. Significant differences among treatments were determined by Du ncan's new multiple range test (Duncan, 1955). Feed intake data from Week one was omitted from the analysis as it was apparent the birds were adapting to the new feed in this period. Also, since the presence of squa b influences feed intake, squab number was used as a co variate when statistical analyses of feed intake, CP intake, and ME intake were performed, Covariance analy sis greatly improved the model. Crude 35 protein was determined by Macro-Kjeldahl analysis of feeds; ME values were calculated from the poultry ME values of NRC (1984) for ingredients. Feed intake data were analyzed as a nested design, with replicates nested within diets, using PROC GLM (SAS, 1985). Significant differences among least squares means (LSM) were determined by testing the hypothesis HO: LSM(i) = LSM(j), according to SAS (1985). 36 Results: Feed intake (adjusted for presence of squab) showed a significant (p<.05) treatment effect (Table 2). Birds on HPC treatment had higher Intake than those on LPC and HP. Birds fed LP had intake that was intermediate and not significantly (p>.05) different from any other treatment. Crude protein (CP) intake showed a significant (p<.05) treatment effect, with the following results: Birds on the HP treatment ate more than those on both the HPC and LP treatments, which ate more than those on the LPC treatment (Table 2). Metabolizable energy (ME) intake showed a significant (p<.05) treatment effect, with the following results: Birds on HPC treatment consumed more ME than those on both the LP and LPC treatments, which consumed more than those on the HP treatment (Table 2). Squab weight at 4 weeks of age exhibited a significant treatment effect (Table 3 and Figure 1). The squab produced by adults on LPC treatment were significantly (p<.05) lighter than those on other treatments. No significant (p>.05) treatment effects on squab weights were exhibited at 1, 2, and 3 weeks of age. 37 TABLE 2. Effect of Dietary Treatment on Feed and Nutrient Intake, Experiment One TREATMENT LP LPC HP HPC" (per pair per week) Feed Intake(g) 810.43"" 741.35h 739.08b 881.24" i. SEM 32.7 31.9 32.6 32.4 CP Intake (g) 132.16" 91. 21* 163.66* 121.99" +. SEM 5. 2 5. 1 5. 2 5. 2 ME Intake (kcal) 2381" 2359" 2058° 2787" + SEM 101 98 101 100 CP Intake/Feed Intake 16.3 12.3 22.1 13.8 ME Intake/Feed Intake 2938 3182 2785 3163 ' • " •c Means with different superscripts within rows are significantly different (p<.05) CP=Crude Protein; values derived from Kjeldahl analysis of feeds ME=Metabolizable Energy; values calculated from NRC (1984) values for ingredients SEM=Standard Error of the Mean TABLE 3. Treatment Effects on Body Weight of Growing Squabs, Experiment One Weight at TREATMENT Age LP LPC HP HPC* (grams) One Week 237.63" 250.48" 238.31" 245.19" +. SEM 7. 1 12. 3 6. 4 8. 3 Two Weeks 478.70" 461.12" 469.62" 473.87" + SEM 9. 8 11. 5 7. 7 8. 3 Three Weeks 592. 79° 562. 03" 583. 62" 588. 24" +_ SEM 7.1 9. 7 8. 6 8. 7 Four Weeks 602.94" 560.08" 595.92" 592.88" + SEM 10. 4 12. 5 9. 1 8. 7 "• b Means with different superscripts within rows are significantly different (p<.05) SEM = Standard Error of the Mean FIGURE 1. EFFECT OF DIETARY TREATMENTS ON BODY WEIGHTS OF GROWING SQUABS EXPERIMENT ONE 700-1 WEEK OF AGE 40 Mortality of squabs exhibited significant (p<.05) treatment effect (Table 4). The dilution of protein by corn in the LPC treatment apparently adversely affected squab livability, as this treatment had the highest (p<.05) squab mortality. Cafeteria-style availability of corn affected adult body weight (Table 5). Birds allowed free access to corn did not gain weight, whereas those fed only pellets did gain weight. Female pigeons were significantly (p<.05) lighter than males. Production traits (egg production, fertility of eggs, hatchability of fertile eggs, weight of squabs produced and number of squabs produced) were not significantly (p>.05) affected by either availability of corn or protein level in the diet (Table 4). Adult mortality was not significantly (p>.05) affected by treatment (Table 4). Discussion: The objectives of this experiment were a) to determine the protein requirements of pigeons and b) to see if the feeding program of a high protein pellet fed with corn, cafeteria-style, could be replaced by feeding a single, lower protein pellet. The two treatments, HPC and LP, were expected to 41 TABLE 4. Production Traits of Pigeons Fed pellets of Different Protein Levels, fed with or without corn, Cafeteria-Style, Experiment One TREATMENTS LP LPC HP HPC Egg Production /pair/9 weeks 1.76" 2.18" 1.67" 1.74" Egg Fertility % 93.2* 96.4* 91. 5* 86.3" Egg Hatchability % 62.1" 63.4* 57.4" 58. 8" Egg Breakage % 11.1 11.3 9. 6 10. 2 Squab Mortality #died/#hatched 2/38* 5/44" 1/38° 0/40° Squab Production kg/trt 21.7" 21. 8* 21.6" 23.7" #/trt 38* 44* 38" 40* Mean 4-week squab weight (g) 602.9" 560.1" 595.9" 592.9* +. SEM 60.6 79.4 54.7 58.9 Adult Mortality1 •# 1* 4° 3* 4* *• bMeans with different superscripts within rows are significantly different (p<.05) SEM = Standard Error of the Mean 'Out of 68 birds 42 TABLE 5. Effect of dietary treatment on initial and final adult body weights, Experiment One TREATMENT Body Weight LP LPC HP HPC < grams) INITIAL Males 630.5" 628.1" 606.9" 622.7" + SEM 9. 9 7.9 8. 5 8. 4 Females 523.2" 552.2" 535.3" 541.9" + SEM 11.7 13.0 9.4 11.0 FINAL Males 670.2" 628.2" 630.2" 623.5" + SEM 11.7 8. 7 9. 4 11. 0 Females 568. 0° 549.7" 561.2" 53S. 4rt + SEM 11.7 12.5 9.7 13.8 CHANGE Males +39.7" +0.1" +23.3" + 0. 8e Females +44.8" -2.5° +25.9" -3.5" *,»,c,dMeans with different superscripts within rows are significantly different (p<.05) (-) means loss of weight, (+) means gain of weight SEM = Standard Error of the Mean 43 give the best results, HPC because the birds could balance their ration through free choice access to corn, and LP because the pellet was formulated to be complete (using available information). The results of this experiment indicated that the squabs of the birds fed a low protein pellet with corn, cafeteria-style (LPC), were underconsuming protein. This is evident from their lower 4-week body weight. Although the breeder flock itself was not affected (production traits and body weights were maintained), the squabs produced on this treatment were. They were smaller at harvest age and they also had the highest squab mortality rate. When the mortality is examined more closely (Appendix 1), this treatment was the only one to show any actual poor health of squabs--mortality in the other treatments can be attributed to accident. The 2 sickly squabs in this treatment developed poor health late in the experiment; it would have been interesting to continue the experiment to see if this was the trend towards sickly squabs in LPC treatment. While the squabs of LPC treatment were being fed crop milk (Week 1), they had the fastest (though non• significant) growth rate. Once the diet of these squabs v/as changed to that of their parents, their 44 performance (relative to that of other treatments) suffered, and by 4 weeks of age, this effect on performance was significant (p<.05). It is generally assumed that birds fed ad libitum will eat to satisfy an energy requirement (NRC,1984). The birds on LPC diet had the option of eating only the LP (16% crude protein) pellets and ignoring the corn (9.6% crude protein), thereby providing more protein to their squabs. However, they did not do this, possibly because the corn had greater energy concentration than LP pellet (3350 and 2937 kcals ME per kilogram, respectively). The fact that adult birds in both treatments that were provided with corn cafeteria-style (LPC and HPC) did not gain weight suggests that these birds were better able to meet their requirements for body weight maintenance than those not afforded corn, cafeteria-style. The feeding of a high protein pellet without supplemental corn likely caused the birds on HP to overconsume protein. Even though they had the lowest feed intake (significantly different from only HPC) and lowest ME intake (significantly different from all other treatments), their CP intake was highest of all the treatments. Since the extra protein in the HP diet, fed alone, did not improve production (Table 2), it seems unnecessary and wasteful to provide such a high protein diet to squabbing pigeons. The adults on HP gained weight, even at such low ME intakes. No explanation for this observation is obvious. The protein requirements of squabbing pigeons appear to be around 17.4 to 18.9 grams CP per pair per day (energy intake around 335 to 345 kcals ME per pair per day). Assuming feed intake of 105 to 125 grams per pair per day, a diet should contain 13.9 to 18. 0 % crude protein. The cafeteria feeding programs of HPC and LPC gave variable results. The low protein pellet plus corn ration did not provide adequate protein to the growing squabs, therefore the squabs were smaller at market age than their counterparts on other treatments. There was also an increased squab mortality noted on this treatment. On the other hand, the HPC treatment gave favourable results, and in fact, they had no squab mortality (although this was not significantly (p>.05) different from any treatment except LPC). These results indicated that if the feeding of corn with pellets is to be practiced, the pellet must be of sufficiently high protein to meet the demands for squab growth. Under the conditions of this trial, the optimum protein level for a cafeteria-style feeding 46 program cannot be determined, however the 2.1V. pellet performed well. Overall, the birds on LP treatment performed well, and the results of this experiment suggest that the cafeteria feeding program (HPC) can be replaced by a single pelleted ration such as LP, without affecting squab production. The LP pellet appears to be the better choice of the two pellets as the birds on HP treatment were apparently overconsuming protein (and possibly underconsuming energy). Since protein is an expensive ingredient in rations, it is wasteful to include it at levels not optimally utilized by the birds. EXPERIMENT TWO EFFECT OF SOURCE AND CONCENTRATION OF DIETARY ENERGY ON THE SQUAB PRODUCTION OF A PIGEON FLOCK IN PAIR-CAGES Introduction: The results of Experiment One showed that the cafeteria feeding program (a high protein pellet fed with corn, ad. libitum) could be replaced by a single pelleted diet, such as LP in Experiment One. In order to generate accurate feed intake data, a cage system was needed in which the production and intake data of single pairs of birds could be monitored. Hence, the U.B.C. Pigeon Nutrition Unit was established. In this system, each pair of birds (plus any squab being raised) could constitute an experimental unit. With the establishment of this unit, other questions relating to pigeon nutrition could be examined. For example, since pigeons are granivorous, the question arises as to whether there would be a differential utilization of animal tallow and vegetable oil, or if, in fact, a supplemental fat source is required. The significance of the effect of fat source on animal performance has been documented in other avian species. In general, oils of plant origin with high levels of unsaturated 47 48 fatty acids are more completely digested by birds than animal fats, such as lard and tallow, which contain higher proportions of saturated fatty acids (Carew et al., 1964; Vermeersch and Vanschoubroek, 1968; Bragg et al., 1973; and Whitehead and Fisher, 1975). Addition of fat to a low-fat basal diet stimulates weight gain in chickens (Biely and March, 1954; Donaldson et al. , 1957; Rand et al., 1958; Dam et al., 1961; Sell and Hodgson, 1962; Versmeersch and Vanschoubroek, 1968; Bragg et al., 1973; and Horani and Sell, 1977) and turkeys (Joshi and Sell, 1964). Crop milk is a substance rich in fat, consisting of lipid-laden desquamated crop cells, hence there may be a need for additional fat during crop milk synthesis. In addition to monitoring feed intake more accurately, the objective of this trial was to study the energy requirements of squabbing pigeons housed in pair- cages. This was accomplished by supplementing a basal diet with fat of plant or animal origin, and recording the effect of supplementation on squab production of pigeons. 49 Materials and Methods: One hundred and forty-four pairs of adult White and Silver King squabblng pigeons were obtained from VIM. The majority of these were the same birds used in the previous experiment. Approximate age of the pigeons was three years old for males and unknown for females. Males and females were assigned to pair-cages at random. In each of three rooms (Room 6, 7 and 8), there were three cage-units. Each cage-unit consisted of 16 pair-cages in 2 tiers of 4 cages, front and back, for a total of 48 pair-cages per room. Pair-cages measured 60 x 60 x 45cm» and each was equipped with a feeding trough, an automatic drinking cup (Hart-type) and two nesting sites. Paper pulp nesting bowls and burlap were provided for nesting. For fifteen weeks before the trial, the birds were fed a commercial pigeon pellet (Otter Co-op, 1985) and their rates of egg production and feed intake were monitored. All eggs were collected as they were laid, thereby preventing the birds from raising squab. Only those pairs that laid eggs of good quality on a consistent basis were used for the trial, so that unproductive birds would not be used. Birds were 50 medicated in the adaptation period, with aureomycin (100 mg per tonne) via feed and piperazine via waterers (according to directions on label). Birds were maintained on a 14-hour light regime (14L:10D). Feed and water were provided ad_ libitum. Based on the results of Experiment One, the following diets were formulated (Table 6). The five treatments consisted of a basal diet (containing no additional fat), to which 2 levels (3% or 6%) of two different fat sources (sunflower oil (SFQ) or animal tallow (AT)) were added. Composition of the diets was manipulated to provide 15.0% crude protein (based on the results of Kjeldahl analysis of ingredients) and ME levels of 2650, 2900, and 3150 kcal/kg feed (calculated from N.R.C., 1984). The feed was steam-pelleted. The 3% SF0 diet closely resembles the diet (LP) used in Experiment One. One hundred and five pairs of pigeons were used in this trial and were distributed in a balanced fashion throughout the three rooms on the basis of body weight, breed, egg production, and feed consumption, to minimize the between-room variation. In a completely randomized block design, pairs were randomly assigned, within rooms, to one of five treatments, 7 pairs per treatment per room. Five 51 TABLE 6. Composition of Diets fed in Experiment Two TREATMENT Ingredient Basal 3V.SF0 6%SF0 3%AT 6%AT (*/. in diet) Alfalfa Meal 3. 5 3. 5 3. 5 3. 5 3. 5 Ground Corn 60. 4a 62. 44 63. 80 62. 39 65. 28 Soybean Meal 10. 35 12. 60 14. 33 11. 39 13. 99 Wheat Middlings 18. 67 11. 46 6. 00 14. 73 6. 0 Dical. Phos. 0. 5 0. 5 0. 5 0. 5 0. 5 Vit-Min Premix1 1. 0 1. 0 1. 0 1. 0 1.0 Bone Meal 2. 0 2. 0 2. 0 2. 0 2. 0 Eggshell Waste 1. 5 1. 5 1. 5 1. 5 1. 5 Cornstarch --•- --•- -- - . 24 Cellulose 2. 0 2. 0 1. 4 - Sunflower Oil 3. 0 6. 0 --•- Animal Tallow 3. 0 6. 0 Calculated Analysis: Protein */.a 15.0 15.0 15.0 15.0 15.0 ME kcal/kg3 2650 2900 3150 2900 3150 Ca % 1.389 1.387 1.386 1.388 1.385 Total P */. 0.754 0.710 0.676 0.731 0.678 1 Vitamin-Mineral Premix as in Experiment One. aAccording to Kjeldahl analysis done on ingredients 3 According to values for ingredients (NRC, 1984) 52 additional palre were put on experimental diets, in case of mortality in experimental birds. Seven pairs of birds represented a replicate. The duration of the trial was 21 weeks (October 1985 to March 1986), during which time the following parameters were recorded: weekly feed intake of pairs; egg production per pair; fertility of eggs (excluding cracked and broken eggs); hatchability of fertile eggs; mortality of hatched squab; squab growth through the 4 week growth cycle; and mortality of adults. Body weights of adults were recorded at the start and end of the experimental period. The parameters were calculated as in Experiment One, with the exception of feed intake. For each pair, there was a plastic bag, into which was weighed sufficient feed for one week. Feeders were topped up daily from this bag. Feed spillage was minimal, Every week, feed consumption was calculated by difference, Statistical Methods: Fertility and hatchability of eggs were subjected to arcsine transformations according to 2ar (1984) and then to a two-way Analysis of Variance (PROC ANOVA), with treatment and block being the main effects, using Statistical Analysis System (SAS,1985). Egg production was also subjected to two-way ANOVA 53 using SAS <1985>. Initial and final adult body weights were subjected to 3-way ANOVA (with sex, treatment and bloc being the main effects). Body weights of squabs through the growth cycle (Weeks 1, 2, 3 and 4) were analysed by 2-way ANOVA (PROC GLM; SAS, 1985), with block and treatment as main effects. Differences between means were determined by Duncan's multiple range test (Duncan, 1955). Since squab number and weight of squab was pooled across rooms, the data were not analyzed statistically Feed intake displayed effects due to both temperature and presence of squabs. Therefore, these parameters were used as covariates in the analysis of feed intake, ME intake, and CP intake data. (Covariance analysis greatly improved the regression coefficient of the model.) The data was subdivided int three 7-week "squabbing periods", a classification developed by the UBC researchers in 1983 (Waldie et al 1984) to denote the period of time in which a pair of producing pigeons should be able to produce a clutch of squabs. Feed intake data were analyzed using covariance analysis, (SAS, 1985), with number of squabs and temperature as covariates. Significant differences among least squares means (LSM) were determined by testing the hypothesis HO: LSM(i) LSM(j). 55 Results: A significant three-way interaction was observed for feed intake, crude protein (CP) intake, and metabolizable energy (ME) intake data of Experiment 2 (Figures 2, 3, and 4). Although this precludes interpretation of each main effect independently of the other two, the following has been observed. Birds fed the basal diet generally had the highest intake of feed. Birds fed the diet containing 6% animal tallow (AT) had lowest consumption in all cases, except in Rooms 7 and 8, in Period 3. Assuming Period 1 (Weeks 1 to 7) represents intake of adults with no squabs (as very few squabs hatched in Period 1 -- 0, 3, 0, 3 and 2 for Basal, 3% SFQ, &'/. SFO, 3V. AT, and 6% AT, respectively), a fairly consistent pattern arises (Table 7). Feed intake and CP intake show the following trend: Basal > 3*/. SFO and 3% AT > 6% SFO and 6% AT (p<.05). It would therefore appear that the birds fed the lowest energy diet (Basal) will eat more than those fed diets of intermediate energy (3% added fat), which will eat more than those on the highest energy diets (6% added fat). Crude protein intake in Period 1 paralleled the pattern of feed intake, as the diets were formulated to 56 FIGURE 2. FEED INTAKE OF PIGEONS ON EXPERIMENT TWO ROOM 6 2 3 PERIOD ROOM 7 1 2 3 PERIOD ROOM S 1 Lagend o WSTO • «*T a tau ' 2 3 PERIOD 57 FIGURE 3. METABOLIZABLE ENERGY INTAKE OF PIGEONS ON EXPERIMENT TWO ROOM 6 I 1 2 3 PERIOD ROOM 7 i ROOM 8 Legend « WW \ O WSTO • KAT • ran 2 3 PDHOO 58 FIGURE 4. CRUDE PROTEIN INTAKE OF PIGEONS ON EXPERIMENT TWO ROOM 6 V 2 PERIOD ROOM 7 335 0 2 3 KMX) ROOM 8 Lagand * 5 MO • **" » « »' 2 3 •EPJOO TABLE 7. Effect of dietary energy lourot and concentration on feed and nutrient intake* TREATMENT Nutrient Intake basal 3X SPO GX SFO 3X AT GX AT (per 7 paira per week) Feed intake (grama) 4351* 4024* 3740* 3944* 3589" •. SEN 43.4 42.6 43.4 42.8 42.7 CP intake 'Represents data from Period One (Weeks 1 to 7) adjusted for squabs and temperature. ••"••Means within rows with different superscripts are significantly different (p<.05> SEN - Standard Error of the Mean TABLE 8. Effect of dietary energy sourot and level on initial and final adult body weights. Experiment Two TREATMENT Body Waight Basal 3X SPO 6X SPO 3X AT 6X AT (grams)_ INITIAL -- Hales 638.4* 649.1* 631.3* 934.2* 615.0* • , SEN 13.2 11.7 13.3 10.3 11.0 -- Females 633.2* 617.4* 607.4* 614.2* 599.5* • SEN 17.2 17.6 12.0 17.8 12.6 PINAL -- Halee 646.0* 653.4* 648.6* 636.3* 625.1* SEN 12.7 12.8 15.0 8.9 10.4 Pemales 633.2" 623.2" 607.1* 615.0* 595.1* • SEN 16.8 16.6 10.4 21.0 13.4 CHANGE -- Halas 7.5* 4.3* 17.3* 2.0* 10.0* -- Pemales 0 5.8* -0.3* 0.8* -4.4* *•*Means vithln rova with different auparacrlpta ara significantly different (p<.05) SEN • Standard Error of the Mean 61 15% crude protein, while varying dietary energy concentration The ME intakes in Period 1 of birds fed diets containing 6% AT were significantly (p<.05) lower than birds fed diets containing either 3% or 6% SFO (Table 7). Birds on the other treatments (Basal and 3% AT) had ME intakes that were intermediate and not significantly (p>.05) different from either of the above groups. No trend is apparent from this data. Examining the intake of birds fed the Basal diet (which produced no squabs) over the 21-week experimental period (Table 2), a fairly constant pattern is evident (except in Room 7, which may have been influenced by the lighting). There was no significant (p>.05) effect of dietary fat source and level on initial or final adult body weights in this experiment (Table S). As in Experiment 1, males were significantly (p<.05) heavier than females, both at the beginning and end of the experimental period. Adult birds on this experiment did not gain weight over the experimental period. A total of thirty-one squabs were produced during the 21-week experimental period (0, 9, 6, 6 and 10 for Basal, 3% SFO, 6% SFO, 3% AT, and 6% AT, respectively). Two of these squabs died shortly after hatching (one 62 each in 3*/. SFO and &'/. AT. This mortality has not been attributed to treatment effect). Eighteen squabs reached 4 weeks of age by the end of the experiment (0, 6, 1, 5 and 6 in Basal, 3% SFO, 6% SFO, 3% AT, and 6% AT, respectively). Due to the small sample size, statistics are interpreted with caution. Birds fed the Basal diet produced no squabs. Birds fed 6% SFO had only one squab reach 4 weeks of age. Since it was much heavier than all other squabs produced (686.4 grams), and since its large size was not believed to be a treatment effect, its data have been deleted from the analysis. Not all rooms had a complete complement of data for each treatment, therefore, squab data have been pooled across rooms. All squab weights were assumed equal at hatch. Although evidence for chickens indicates that chick hatch weight is directly related to egg size (North, 1978), squab hatch weights are not easily determined as squabs are fed crop milk shortly after hatching. Table 9 shows the body weights of growing squabs over the 4 week growing cycle. At 1 week of age, there was a significant (p<.05) treatment effect on squab body weight, with squabs in the &"/. AT treatment being significantly heavier than those in other treatments. At 2 weeks of age, there was a significant (p<,05) TABLE 9. Mean Weekly Body Weights of Growing Squabs in Experiment Tvo TREATMENT Age of Squab Basal 3X SPO 6X SFO 3X AT 6X AT (grams) 1 Week Mean — 172.56- 148.17* 143.98* 224.71* n- 7 5 6 7 SEM 7.3 18.7 15.1 13.6 2 Weeks Mean 391.94*• 362.50* 323.74* 439.78* n- 6 4 5 7 SEM 19.1 48.6 13.5 12.3 3 Weeks Mean 539.45* 457.25* 486. 18* 543.89* n- 6 4 5 6 SEN 33.3 51.3 31.2 16.8 4 Weeks Mean 554.31* 518.46* 553.27* n*> 6 0 5 6 SEM 20.4 39.6 13.5 •••Means within rows with different superscripts are significantly different (p<.05) Basal Diet produced no squabs; 6X SFO had no squab attain 4 weeks of age SEM • Standard Error of the Mean; n« number of values used in analysis 64 treatment effect as well, in the same direction , but at 3 and 4 weeks of age, body weights of squab were not significantly (p>.05) different among treatments. There is the additional complication of one- versus two-squab clutches. Squabs from one-squab clutches are generally heavier than those from two-squab nests (Table 10). Within treatments, there were equal numbers of one- and two-squab clutches (see Appendix 3), however, not all squabs attained harvest age by the end of the trial. Overall, of those squabs that reached harvest age, 4-week old squabs from one-squab clutches (n=6) were 29.9 grams heavier than those from two-squab clutches Table 11 shows the production traits of pigeons fed different dietary energy sources and levels. Fertility and hatchability of eggs in this experiment showed no significant (p>.05) differences among treatments (except the basal diet, in which birds produced no squabs). Egg production showed no significant (p<.05) treatment effect, however, this trait did display a room effect, with Room 7 producing significantly (p<.05) fewer eggs than the other rooms (17.6, 11.3 and 16.1 eggs per 7 pairs per week in Room 6, 7 and 8, TABLE 10. Comparison of maan body vaights of squabs raised aa one- versus two- squab nests. Experiment Tvo TREATMENT Age of Type of Squabs Nest 3X SPO 6X SPO 3X AT 6X AT Overall (grams) 1 Week One-squab 163.7 161.8 99.6 217.4 169.4 • SEN 2.6 41.6 0 15.0 19.3 Tvo-squab 176. 1 159. 5 155. 1 230.2 178. 3 • SEN 9. S 16.7 11. 5 18. 5 10.0 2 Weeks One-squab 450.6 386. 1 336.3 448.9 408.0 •. SEN 46.0 83. 1 0 9. 7 28. 3 Tvo-squab 372.4 409.5 315.8 433.0 386.9 • SEN 12.5 15.2 13.2 17.8 13.0 3 Weeks One squab 611.4 635.0 485.8 578. 1 572.9 • SEN 50.0 0 0 32. O 78.5 Two-squab 503. 5 542.5 486.2 526.8 493. 5 SEN 22.0 44.5 34.8 7. 5 16. 5 4 Weeks One-squab 585.7 686. 4 490.0 581. 7 564. 5 •. SEN 19. 3 0 0 15. 1 19. 4 Two-squab 523.7 525.6 539.6 534. 6 • SEN 22. 4 43.4 12. 1 16.9 SEN - Standard Error of the Hean TABLE 11. Effect of dietary energy aourc* and concentration on pigeon production traits. Experiment Tvo TREATMENT Production Traits Basal 3X SPO 6X SPO 3X AT 6X AT (per 35 pairs) Egg Production* # of eggs/21 weeks 218* 151- 200- 189« 187" Egg Fertility X 92.3- 68.2* 79.4- 90. 6* 88.6* Egg Hatchability X 0.0 64.3 21.0 21.4 66.7 Squab Mortality #died/# hatched 0/0 1/9 0/6 0/6 1/10 Squab Production' #hatched/trt 0 9 6 6 10 kg produced/trt 0 4. 18 2.71 2.70 3.77 Mean 28-day weight 334.31* 518.46* 553.27- Adult Mortality #/70 birds 1 0 0 0 0 •Means within rows with different superscripts are significantly different (p<.05) 'Egg production showed a significant (p<.05) room effect "Basal diet produced no squabs; one 6X SPO squab omitted from analysis 67 respectively) (Figure 5). This, no doubt, relates to the fact that for the first 8 weeks of the trial (and for an unknown quantity of time before the experiment began), the lights in Room 7 were not properly synchronized, hence the bix-ds were unintentionally exposed to a 24-hour light regime (24L:0D). By Week 10, however, 2 weeks after adjustment of the light regime, egg production in Room 7 had increased to approximate that of other rooms. Adult mortality was not attributed to treatment. One adult on the basal diet died. Birds fed 37. SFO produced the greatest weight in kilograms of squab meat. This figure was calculated by summing 4-week squab weights of those squabs that attained 4 weeks of age and the weight of squabs left in the nest at the end of the experimental period. Kilograms of squab produced were 4.18, 2.71, 2.70, and 3. 77 for 3'/. SFO, 67. SFO, 37. AT and GY. AT, respectively. Number of squabs produced were 0, 9, 6, 6 and 10 for Basal, 37. SFO, 67. SFO, 37. AT, and 67. AT, respectively. Since data were pooled across rooms, no statistical analysis was performed. Artificial incubation was implemented at Week 16 of the experiment. Table 12 shows production data from before and after incubation was initiated. FIGURE 5. EGG PRODUCTION EXPERIMENT TWO 69 TABLE 12. Effect of mode of incubation (natural or artificial) on squab production Production Natural Artificial Trait Brooding1 Incubation1 Eggs produced per week 43.5 48. 7 Squab hatched per week 1.2 2. 2 Fertility of Eggse 98.4 83.1 Hatchability of Eggs3 9.5 11.0 Egg Breakage4 64.9 56.0 Eggs Missing3 17.0 8.2 'Natural brooding occurred for 16 week; artificial incubation was implemented for 5 weeks a/.fertility of eggs = #laid - #infertile / #laid - #broken - #missing X 100'/. 3%Hatchability = [#hatched / (#laid - #broken - #missing)3 X 100% 4 '/.Breakage = #broken / #laid -#missing X 100% '•/.Missing = #missing / #laid X 100% 70 Discussion; Birds on Basal diet (no supplemental fat) produce no squabs, whereas all other treatments produced at least 6 squabs. This could not be attributed to egg production or fertility, as these parameters were not significantly (p>.05) different among treatments. Despite the low production of squabs in this experiment, it suggests that the Basal diet does not contain enough fat to support squab production. Pigeons fed diets containing different sources an levels of dietary fat had different levels of feed intake. There was a significant (p<.05) three-way interaction on feed, CP and ME intakes in this experiment; however, in general, these followed expected trends. Pigeons apparently eat to meet an energy requirement when not producing squabs , as do other avian species (NRC,1984). This is derived from the fact that, in Period One, although there were significant differences among ME intakes of the different treatments, there were no observable trends. Also, the feed intake data show such clear-cut differences between the three levels of fat inclusion (0, 3 and GX) that it is difficult to reject the idea that energy intake is not the determining factor (Tabl 7). This requirement is approximately 235 kcal ME per pair of pigeons per day. 71 In contrast to the results of Experiment One (in which those birds fed a single ration gained weight over the experimental period), the birds in Experiment Two did not gain weight, although they were all fed a single ration (as opposed to cafeteria-style). Possible explanations for this could be differences in production pressure, housing and/or environmental temperature. Birds in Experiment Two were under very little production pressure, and the experiment was carried out during the fall and winter months. Experiment One was carried out in the summer months and the birds were under much greater production pressure than those of Experiment Two. Birds in Experiment One were maintained in a pen situation, interacting within a social hierarchy. Those in Experiment 2 were in a pair situation and, presumably, under no between-pair social pressure. The question therefore arises as to whether or not social behaviour (competition) affects feed intake of pigeons. Pair-cages have been reported to affect courtship behaviour (Hollander, 1945)-- perhaps feeding behaviour is affected as well. Squab production in this trial can be attributed to 13 pairs of birds (3,3,3 and 4 in 3V. SFO, &'/. SFO, 3% AT and 6% AT, respectively). Although the birds were randomly distributed among the treatments at the start 72 of the experiment, pair production could only be described as minimal (see housing discussion, page 73). As a result, variations among the pairs would take on greater significance. If, by chance, the 4 pairs in the 6% AT group that produced squabs were better feeders than the pairs producing squabs on other treatments, they could significantly affect body weight of the squab. This agrees with the data of Cheng (1985), who reported that the parents' brooding ability had greatest importance in influencing squab body weight when the squabs were young, becoming less important as the squabs grew older. This may account for the results of body weights of growing squabs (Table 9). At 1 week of age, there was a treatment effect, but by week 3, it had disappeared. Conversely, if adults in the other treatments were poor brooders, their squabs would be at a disadvantage for the first 2 week of life. The erratic feed intake data raises the question as to how sensitive pigeons are to the requirements of their squabs. It may be that as long as the diet is adequate, the birds will attempt to raise squabs. The literature cites incidences of pigeons surviving and raising squabs on little more than corn, grit and water (Carr and James, 1932). Once the squabs hatch, is feed 73 and nutrient intake related to the actual value of the diet or is it simply a response to feed the squabs as much as they will eat? The latter would perhaps explain why covariance analysis could not explain more of the variation in the feed and nutrient intakes. Also, referring back to Experiment One, the adults on the low protein diet with corn (LPC), whose squabs were affected by a low protein intake, still ate the corn, even though it was not meeting the requirements for their squabs' growth. In Experiment Two, those birds not producting squabs (basal diet) show fairly consistent intake patterns, as do all treatments in Period 1 (with no squab). It is apparent that those birds not producing squabs are sensitive to their own nutritional requirements. It is during the brooding of squabs that the feed intake patterns fall apart. Under conditions of this trial, fat source and concentration appear to have no influence on squab production, except that the Basal diet (Q'A added fat) did not support squab production. The cage system devised for this experiment was not satifactory for squab production under conditions of this experiment. A prototype of this cage system has been used successfully at UBC (Cheng, pers. comm.). However, in this experiment, a high proportion of 74 cracked and broken eggs (62% of total) resulted in few squabs being produced. Possible explanations for the differential squab production between this flock and that of the other UBC project are: a) this flock was older, was used to a pen system, and may not have adapted readily to cages; and b) perhaps our own modifications of the nest designs rendered the cages less desirable to nesting pigeons. In order not to complicate the experimental design and bias any treatment, the cage design was not modified further. Instead, artificial incubation was implemented at Week 16 of the experiment. All eggs were gathered from the cages and tested for soundness; uncracked eggs were placed in an incubator. From this point until the end of the experiment, eggs were collected daily, and the number of cracked and/or broken eggs exhibited a marked decrease (64.9% and 56.0% pre- and post-incubation, respectively) (Table 12). Wooden eggs were placed under the nesting adults, a technique that has proved successful with the other U.B.C. pigeon flock (Cheng, pers. comm.). The use of wooden eggs with this flock was, however, less successful, with some eggs rolling from the nest site or being abandoned before the artificially-incubated squabs could be replaced to the parents. To counteract this problem, the fertile eggs 75 were then returned to the adults after 16 days of artificial incubation and allowed to pip and hatch in the nest. Regrettably, by the time this successful collection and incubation technique had been developed, the experiment was near completion, and those squabs that had been artificially incubated were not of market age (4 weeks old). As shown in Table 12, egg production apparently increased once artificial incubation was started, however, this was probably not due to the incubation procedure but rather due to an increase in egg production in Room 7. The overall production of squab was greatly improved by the incubation technique, increasing from 1.2 squabs per week to 2.2 squabs per week ( for all treatments). Fertility of eggs apparently declined due to this procedure, possibly due to the better observation (and survival) of the eggs once the incubator was being utilized. A total of only 3 eggs (out of 653 laid) were recorded as being infertile in the first 15 weeks, whereas 20 (out of 292 laid) were recorded thus in the last 6 weeks. Number of eggs broken and missing decreased dramatically once daily egg collection commenced (from 70.9% before to 59.6% after commencement). Feed and nutrient intake in Room 7 showed a con- 76 sistent peak in Period 2, in all treatments but &'/. AT. This peak appears to cause generally greater variability in Room 7 than in Rooms 6 and 8. This may be a result of the inconsistent lighting in Room 7 during weeks 1 to 8. 77 SUMMARY AND CONCLUSIONS A developing squab-producing industry in B.C. has stimulated interest in providing a sound, balanced, pelleted feed for this industry. Commercial pigeon producers have traditionally fed their birds a mixture of whole grains plus a health grit. Feeding a high protein pellet with corn, free choice, has been gaining popularity (Legge and English, pers. comm.). The high cost of corn in B.C., plus the extra manpower required to maintain availability of corn to the pigeons, led to this research into the development of a feed for the B.C. squab industry. Two experiments, based on the results of Waldie et al.(1984), were carried out. In Experiment One, the protein requirements of squabbing pigeons were evaluated. Two pellets of differing protein levels (22% and 16% crude protein), were fed, with and without corn. This experiment was carried out at the commercial operation of VIM in Lantzville, B.C. The results of this experiment indicated that a low protein diet (low protein pellet plus corn) adversely affects squab growth, without affecting egg production parameters or body weight of the adults. A high protein diet (high protein pellet 7a fed without corn) did not affect squab production in the conditions of this trial. The Low Protein (LP) pellet, fed without corn, resulted in good squab production. In Experiment Two, the requirement for and utilization of different fat sources, included at different levels into the diet, was evaluated. This experiment was carried out at the new Pigeon Nutrition Unit at U.B.C., where the pigeons were housed in pair cages. The 5 treatments in this trial were as follows: A Basal diet with 16% protein and no added fat, to which was added 3% or 6% sunflower oil (SFO) and 3% or 6% animal tallow (AT). Birds fed on a basal diet without any added fat, produced no squabs, whereas all other treatments produced at least 6 squabs. This could not be attributed to lower egg production or fertility, but to lower hatchability. Pigeons apparently eat to meet their energy requirement when under no production stress. For example, the pigeons in Experiment Two did not gain weight. This contrasted the results of Experiment One, where the availability of corn seemed to influence weight gain. This may relate to the lack of production pressure for birds in Experiment Two, or it may be a 79 result of a change in housing. Birds in Experiment One were maintained in a pen situation, interacting within a social hierarchy, whereas those in Experiment 2 were in a pair situation, and presumably under no social pressure. The question, therefore, arises as to how much social behaviour affects feed intake. Since the birds in Experiment 2 produced few squabs, this raises the question of how sensitive these birds are to nutrient requirements when they have squabs. Those birds without squabs have the "leisure" of being able to choose their ration to meet their own requirements,, whereas those with squabs may be simply eating to fill the "bottomless" crop of the squabs. Overall, in Experiment 2, there was no effect on squab production due to dietary fat source or concentation, except that 07. supplemental fat seemed to be detrimental to squab production. ao LITERATURE CITED Ahderhalden E., and E. Wertheiuer, 1932. Uber das verhalten des glykogens im organismus bei abwesenheit des vitamin-B-komplexes des vitamins B4 > in der Nahrung. Pflugers Archiv ges. Physiol. 230:601-613. Abs, M.(Editor), 1983. Physiology and Behavior of the Pigeon. Academic Press, Inc., (London), Ltd. Beams, H.W., and R.K. Meyer, 1931. The formation of pigeon milk, Physiol. Zool, 4:486-500. Biely, J. and B.E. March, 1954. Fat studies in poultry 2. Fat supplements in chick and poult rations. Poult. Sci. 33:1220-1227. Bragg, D,B., J.S. Sim, and G.C, Hodgson, 1973. Influence of dietary energy source on performance and fatty liver syndrome on White Leghorn laying hens. Poult. Sci. 52:536-540. Burley, N., and N. Moran, 1979. Significance of age an reproductive experience in the mate preference of feral pigeons (Columba livia). Anim. Behav. 27:686-698. Carew, L. B. , Jr., D. T. Hopkins, and M.C. Nesheim, 1964. Influence of amount and type of fat on metabolic efficiency of energy utilization by the chick. J. Nutr. 83:300-306. Carr, R. H. , and CM. James, 1931. Synthesis of adequate protein in the gands of the pigeon crop. Amer. J. Physiol. 97:227-231. Carter, C. W. , and J.R. 0'Brie 1939a. Ma nutrition in the pigeon. Further evi ials in yea min B& . Bi 33:1810-1815. Carter, C. W. , and J.R. 0'Brie 1939b. Vi complex in relation to i nutrition and pigeon. Proc. 7th World's Poultry Congress (1939) pp.126-128 Cheng, K.M., 1986. UBC search for squab production efficiency. Country Life, June 1986. p.A6. ai Cheng, K.M., 1985. Final progress report for Project #21(RC-11), Science Council of British Columbia. Clarkson, T. B. , R. W. Prichard, H. B. Lof land, and H. 0. Goodman, 1963. The pigeon as a laboratory animal. Lab. Animal Care 13:767-780. Cramer, E.B., and S.C. Smith, 1976. Yolk lipids of developing atherosclerosis-susceptible White Carneau and atherosclerosis-resistant Show Racer pigeon embryos. J. Nutr. 106:627-630. Dam, H., F. Schonheyder, and L. Lewis, 1937. The requirement for vitamin K of some different species of animals. Biochem. J. 31:22-27. Dam, R. , R. M. Leach, Jr. , T. S. Nelson, L. C. Norris, and F.W. Hill, 1959. Studies on the effect of quantity and type of fat on chick growth. J. Nutr. 68:615- 632. Davies, W.L., 1939. The composition of the crop milk of pigeons. Biochem. J. 33:898-901. deLima, M.A.I., 1978. Lipid droplets in the lining epithelium of the crop of Columba livia. Acta Anat. 101:153-159. Desmeth, M., and J. Vandeputte-Poma, 1980. Lipid composition of pigeon cropmilk. I. Total lipids and lipid classes. Comp. Biochem. Physiol. 66B:129- 133. Desmeth, M., 1980. Lipid composition of pigeon cropmilk. II. Fatty acids. Comp. Biochem. Physiol. 66B:135- 138. Donaldson, W. E. , G. F. Combs, G.L. Romoser, and W. C. Supplee, 1957. Studies on energy levels in poultry rations. 2. Tolerance of growing chicks to dietary fat. Poult. Sci. 36:807-815. Dumont, J.N., 1965. Prolactin-induced cytological changes in the mucosa of the pigeon crop during crop "milk" formation. Zeitschrift fur Zellforschung und Mikroscopische Anatomie. 68:755- 782. Duncan, D.B., 1955. Multiple range and multiple F tests. Biometrics 11:1-42. 82 Emmett, A.D., and G.E. Peacock, 1923. Does the chick require fat-soluble vitamin A? J. Biol. Chem. 56:697-693. El-Sayed, W. A. , A. H. Shehab, F.E. Mourad, F.I. El-Nahy, A.K. Said, 1980. Biochemical and biological evaluation of pigeon meats. Effect of type, age and sex. Nahrung 24:821-828. Ewing, W.R., 1963. Poultry Nutrition, 5th Edition (revised). Hoffman-LaRoche, Inc. Nutley, N.J. Giammettei, V.M., 1976. Raising Small Meat Animals. Interstate Printers and Publishers, Inc., Danville, 111. Goodman, H.M., and P. Griminger, 1969. Effect of dietary energy source on racing performance in the pigeon. Poult. Sci. 48:2058-2063. Guareschi, C., 1936. Necessita di fattori alimentari materni per laccrescimento del giovanissimi columbi. Boll. Soc. Ital. Biol. Sper. 11:411-412. Harris, C., 1939. Chem. and Ind. 58:471. Hegde, S.N., 1972a. The amino acid composition of pigeon milk. Current Science 41:23-24. Hegde, S.N., 1972b. The lipid composition of pigeon milk. Experentia 28:1451-1452. Hegde, S.N., 1973. Composition of pigeon milk and its effect on growth in chicks. Indian J. Exp. Biol. 11:238-239. Horani, F., and J.L. Sell, 1977. Effect of feed grade animal tallows on laying hen performance and on metabolizable energy of rations. Poult. Sci. 56:1972-1980. Heuser, G.F., 1955. Feeding Poultry, 2nd Edition. Printed in the U.S.A. by G.F. Heuser. Hollander, W.F., 1945. A type of psychopathy in the domestic pigeon. J. Comp. Physiol. Psych. 38: 287- 289. Hollander, W.F., 1954. Pigeons in research. Proc. Anim. Care Panel 5:71-80. 83 Hollander, W.F., and 0. Riddle, 1946. Goiter in the domestic pigeon. Poult. Sci. 25:20-27. Itokawa, Y., 1975. Is calcium deficiency related to thiamine-dependent neuropathy in pigeons'? Brain Research 94:475-484. Joshi, S.K. and J.L. Sell, 1964. Comparative dietary value of soybean oil, sunflower oil, rapeseed oil and animal tallow for turkey poults. Can. J, Anim.Sci. 44:34-38. Jull, M.A., 1947. Raising Turkeys, Ducks, Geese and Game Birds. The McGraw-Hill Book Co., Inc., U.S.A. Leash, A.M., J. Liebman, A. Taylor, and R. Limbert, 1971. An analysis of the crop contents of White Carneau pigeons (Columba livia) days 1 through 27. Lab. Anim. Sci. 21:86-90. Lee, A.R., and S.K. Haynes, 1942. Squab Raising. U.S.D.A. Farmer's Bulletin #684, Revised 1942. Levi, W.M., 1968. Making Pigeons Pay, 3rd Edition, Revised. Levi Publishing Co, Inc., Sumter, S.C., U. S. A. Levi, W.M., 1974. Th Pigeon. Levi Publishing Co, Inc., Sumter, S.C., U. S.A. Liebman, J., A. Leash, R. Benyo, and W.M. Wallace, 1970. Effect of early underfeeding on the weight of the White Carneau pigeon (with some remarks on the possible inhibition of early atherosclerosis). Atherosclerosis 11:439-449. Little, J.M., and E.A. Angell, 1977. Dietary protein level and experimental aortic atherosclerosis. Atherosclerosis 26:173-179. Lloyd, L.E., B.E. McDonald, and E.W. Crampton, 1976. Fundamentals of Nutrition, 2nd Edition. W.H. Freeman and Company, San Fransisco, California. Lofland, H. B., Jr., H.0. Goodman, T.B. Clarkson, and R.W. Pritchard, 1963. Enzyme studies in thiamine- deficient pigeons. J. Nutr. 79:188-194. 84 March, G. L. , B. A. McKeown, T. M. John, and J. C. George, 1978. Diurnal variation in circulating levels of free fatty acids. Growth hormones during crop gland activity in the pigeon (C. livia). Comp. Biochem. Physiol., B. 59:143-145. Martin, D.W., P.A. Mayes, V.W. Rodwell, and Associate Authors, 1983. Harper's Review of Biochemistry, 19th Edition. Lange Medical Publications. McNabb, F. M. A. , R.A. McNabb, and J.M. Ward, Jr., 1972. The effects of dietary protein content on the water requirements and ammonia excretion in pigeons, C. livia. Comp. Biochem. Physiol., A 43:181-185. Moon, R.D., and H.P. Zeigler, 1979. Food preferences in the pigeon (Columba livia). Physiol. Behav. 22: 1171-1182. Murton, R.K. and N.J. Westwood, 1966. The foods of the rock dove and feral pigeon. Bird Study 13:130-146. NRC, 1984. National Research Council, Nutrient Requirements of Poultry, 8th Revised Edition. National Academy Press, Washington, D.C. Nohlgren, S.R., and W.D. Wagner, 1977. Large-scale production of White Carneaux pigeons with reliable pedigrees: Reproductive characteristics and parent-offspring identification. Lab. Anim. Sci. 27:396-403. Normile, H.J., and R.A. Barraco, 1984. Relation between food and water intake in the pigeon (Columba livia). J. Comp. Psychol. 98:76-90 North, M.O., 1978. Commercial Chicken Production Manual, 2nd Edition. The AVI Publishing Co., Inc., Westport, Connecticut. Pace, D.M., P. A. Landolt, and F.E. Mussehl, 1952. The effect of pigeon crop-milk on growth in chickens. Growth 16:279-285. Patel, M.D., 1936. The physiology of the formation of "pigeons's milk". Physiol. Zool 9:129-152 Patrick, H., and P. Schaible, 1980. Poultry: Feeds and Nutrition. The AVI Publishing Co., Inc., Westport, Connecticut. 85 Peeters, N. , N. Viaene, and L. Devrieae, 1977. [Poisoning in pigeons after administration of Vitamin B6 (pyridoxine)]. Vlaams Diergeneeskundig Tijdschrift 46:268-269. (abstract). Pietras, R.J., and B.M. Wenzel, 1974. Effects of androgen on body weight, feeding and courtship behavior in the pigeon. Hormones and Behavior 5:289-302. Piatt, C.S., 1939. Effect of restricting the cereal diet of pigeons to corn and wheat. Proc. 7th World's Poultry Congress, pp. 466-468. Piatt, C.S., 1951. A study of the composition of mineral mixtures for pigeons. Poult. Sci. 30:196-198. Rand, N.T, H.M. Scott, and F.A. Kummerow, 1958. Dietary fat in the nutrtion of the growing chicken. Poult. Sci. 37:1075-1085. Reed, L.L., L.B. Mendel, H.B. Vickery, and P. Carlisle, 1932. The nutritive properties of the "crop milk" of pigeons. Amer. J. Physiol. 102:285-292. Riddle, 0., 1947. Endocrines and Constitution in Doves and Pigeons. Carnegie Institute, Washington, Publication #572. Riddle, 0., and P.F. Braucher, 1931. Studies on physiology of reproduction in birds: control of special secretions of the crop-gland of pigeons by an anterior pituitary hormone. Amer. J. Physiol. 97:617-625. Riddle, 0., T.C. Nussman, and F.G. Benedict, 1932. Basal metabolism during growth in the common pigeon. Amer. J. Physiol. 101:251. SAS (Statistical Analysis System), 1985. SAS User's Guide: Statistics, Version 5 Edition. SAS Institute, Cary, N.C., U.S.A. Sell, J.L. and G.C. Hodgson, 1962. Comparative value of dietary rapeseed oil, sunflower seed oil, soybean oil and animal tallow for chickens. J. Nutr. 76:113-118. Shultz, F. T. , CR. Grau, and P. A. Zweigart, 1953. Vitamin supplements and squab production. Poult. Sci. 32:762-768. 86 Silver, R., 1984. Prolactin and parenting in the pigeon family. J. Exper. Zool. 232:617-625. Skinner, B.F., 1950. Are theories of learning necessary? Psychol. Rev. 57:193-216. Skinner, B.F., 1951. How to teach animals. Sci. Amer, 185:26-29, Suguira, K,, and S.R. Benedict, 1923. A study of the adequacy of certain synthetic diets for the nutrition of pigeons. J. Biol. Chem. 55:33-44. Tudor, D.C., 1982. Vitamin A deficiency in pigeons. Vet. Med. Small Anim. Clin. 77:88-89. Vandeputte-Poma, J., 1980. Feeding, growth and metabolism of the pigeon, Columba livia domestica: duration and role of crop milk feeding. J. Comp. Physiol., B, 135:97-99. Vermeersch, G. and F. Vanschoubroek, 1968. The quantification of the effect of increasing level of various fats on body weight gain, efficiency of food conversion and food intake of growing chicks. Brit. Poult. Sci. 9:13-30. Waldie, G., J. Sim, and D. Kerridge, 1984. Balanced pigeon feeds and feeding program for squab meat production. Poult. Sci. v.63, Supplement, p.200. Ward, G.E., and A. Cryer, 1981. The establishment and maintenance of a colony of White Carneau pigeons. J. Inst. Anim. Techn. 32:71-76. Waters, J.W., 1952. Effect of vitamin A deficiency on the dark adaptation of the pigeon. Nature 169:413- 414. Whitehead, C.C., and C. Fisher, 1975. The utilization of various fats by turkeys of different ages. Brit. Poult. Sci. 16:481-485. Wolter, R., 1971. [Intensive production of pigeons for meat.] Rev. Agric. Fr., Sept. 1971, pp. 28-29, 31. Wortis, R.P., 1969. The transition from dependent to independent feeding in the young ring dove. Anim. Behav. Monographs. 2:3-54. 87 Yanni, M,, 1969. Biophysics of developing eggs and rate of growth of squabs of domestic pigeons. Poult. Sci. 48:1536-1542. Zar, J.H. 1984. Biostatistical Analysis, 2nd Edition. Prentice-Hall, Inc., Engelwood, Cliffs, N.J. 07632. Zeigler, H.P., H.L. Green, and R. Lehrer. 1971. Patterns of feeding behavior in the pigeon. J. Comp. Physiol. Psychol. 76:468-477. aa APPENDIX 1. Squab mortality in Experiment One Date Died Trt. Age Died Cause of Death Sept.11 LP 6-7 days Crop Milk Sample Aug. 20 LP 4 days Eyeless, torticollis July 16 LPC 5 days Disappeared Sept. 11 LPC 2a days Sickly, compacted crop Aug.29 LPC 13 days Sickly, compacted crop Aug.16 LPC 7 days Killed by adults, floor squab Aug. 7 LPC 1 day Crushed Aug. 13 HP 1 day Crushed APPENDIX 2. NUMBER OF SQUABS HATCHED OVER TIME, EXPERIMENT TWO 6-1 5- < 4- o in o 3- or LJ CO 3 2 N * Legend • 6% AT 1- S3 3% AT 1. m 6% SFO Vs. EZ2 3% SFO Ir 10 15 20 25 WEEKS 90 APPENDIX 3. Identification of squabs produced in Experiment Two Treatment Parent Hatch Date #/Clutch Attained I. D. 4 weeks? 3% SFO 7B1 21/01/86 1 yes 8C11 01/01/86 2 yes 8A8 01/12/85 1 yes 8C11 27/02/86 2 yes 8C11 13/11/85 2 yes 8A8 10/01/86 1 died 6% SFO 6A3 03/03/86 2 no 7B1 07/01/86 1 yes 7B1 24/02/86 2 no 7A1 06/03/86 1 no 3% AT 6C11 30/11/85 2 yes 6A13 12/03/86 1 no 8B6 22/11/85 1 yes 8B6 11/02/86 2 yes £>Y. AT 6A12 19/01/86 1 yes 8C13 12/11/85 1 yes 8A4 27/12/85 2 yes 8C13 02/02/86 2 yes SA15 02/03/86 1 no 8A4 16/03/86 2 no 8A15 05/12/85 1 died