5^4 THE YEARBOOK OP AGRICULTURE 1964 Study also must be made of the in- terrelationships between nutrition and susceptibility to illness and mortality from tuberculosis, measles, and other specific infections. If people the world over are to bene- fit from research and understanding of Problems in the principles of nutrition, the results must be interpreted to answer the practical problems faced by family food managers, consumers, teachers, Animal Husbandry physicians, and public leaders and Government agencies that formulate national and international food pro- by RALPH E. HODGSON and grams. Many different combinations NED D. BAYLEY of foods can meet the nutritional re- quirements of normal, healthy persons. Research also is needed to lead to better understanding of why food choices are made and how food habits WE ALL AGREE on the need to improve can be modified. Dependent on such the diets of people in many countries. knowledge is success of programs of We agree also that sources of animal nutrition education and food distri- protein must be expanded in order to bution, as well as all efforts to in- accomplish that. While some of this fluence people to use new or diff'erent protein food may come from local foods. sources of fish, the larger part must Thus, further scientific research is come from farm livestock and poultry. needed to define the zones of intake of The problem then is to increase the essential nutrients that will free people producing ability of livestock and from obvious ill health and will under- poultry—of which many countries gird the highest possible level of have large numbers—by creating con- physical and mental vigor throughout ditions of feeding and management the life cycle and through successive that permit satisfactory performance generations. and by controlling and eliminating Research must then translate the diseases and parasites that cause stag- information into food practices and gering losses of animals and that con- dietary patterns which are practical in tribute to low production. view of economic, cultural, and agri- Through long investigation and ex- cultural potentialities of populations perience, we have found that greatest living in diff'erent parts of the world. returns from animal production, whether it is milk, beef, swine, sheep HAZEL K. STIEBELING was Deputy and wool, eggs, or poultry meat, Administrator y Agricultural Research Serv- come when high animal performance ice, when she retired in ig6^. She joined the is attained. Department in igjo and was named in I g 42 to supervise the Departments research WE HAVE FOUND that i o conditions are program in human nutrition and home eco- needed to achieve successful livestock nomics. and poultry enterprises. RUTH M. LEVERTON, Assistant Ad- The individual farmers should have ministrator, Agricultural Research Service, the interest and ability and potential joined the Department of Agriculture in resources to engage in the enterprise ^957' ^he has special responsibility for the with the prospect of success. program in Nutrition and Consumer-Use The enterprise should be adapted to Research, including human nutrition. the locality, the land, and the climate. PROBLEMS IN ANIMAL HUSBANDRY 565 In establishing livestock or poultry en- An active extension program is re- terprises, adequate information should quired to take the latest research find- be available to the individual. ings from the laboratory to the farmer Access to a market for the product and aid him in applying this new produced should be assured. The knowledge to his production problems. existence of such markets and their availability to the producer have been IN REGIONS where livestock enterprises critical to the incentives for improving have prospered, research is directed the care and breeding of animals. toward making further improvement The livestock and poultry should be in an already efficient industry. adapted to the existing environment. For example, research on nutrition The ability of indigenous animals to and breeding have resulted in a broiler reproduce and to produce efficiently industry that can produce birds of 3.5 and economically should be thoroughly pounds for market in 65 days, com- tested and their abilities utilized. pared to the 91 days needed before the Exogenous types with particularly research findings were applied. adapted qualities should be introduced Research investigators have turned when conditions indicate. their attention to increasing feed effi- Breeding programs, national, re- ciency further by studying the inter- gional, and within herd, should be relationships of minerals, proteins, and developed to improve steadily the other nutrients. producing ability of animals. Record- Geneticists also have undertaken to of-performance programs should be increase feed efficiency by selecting for developed and applied to measure that trait directly; selection previously productivity, to guide management emphasized increased rate of growth practices, and to identify superior of the animals or an increase in pro- breeding stock. Breeding service by duction of milk, eggs, and wool per artificial insemination should be devel- animal. oped and employed to use superior Except for broiler chickens, little germ plasm to improve performance. progress has been made on improving An adequate year-round feed sup- the efficiency with which animals con- ply, based on local farm-produced vert feed to animal products. This forage and grain supplemented with problem must be attacked if the live- concentrate mixes to avoid nutri- stock industry is to advance as it tional deficiencies, is needed. should. Success in the broiler industry An effective program of disease and indicates the potential gains to be parasite control and eradication should made with other farm animals. include an adequate, qualified veter- Studies with all classes of livestock inary service. A livestock industry can- have been started on fat metabolism, not flourish and meet a country's needs deposition of fat in the body, and the for animal foods under conditions of secretion of fat in milk. Efforts to pro- unabated diseases that terminate in duce lean, meat-type hogs through death of animals or produce contin- breeding have been successful. uous ill health and low production. Nutritionists and physiologists are An appropriate sanitary service probing the basic phenomena that should be available to supervise the make hogs different in their use of production, processing, and marketing body fat and its composition. They are of animal products. The development looking for means of controlling fat and maintenance of good markets re- content of the meat by altering rations quire that the foods be wholesome or by other practices. In beef catde, and produced in clean conditions. dairy cattle, sheep, and poultry, simi- A strong research and development lar problems are being studied. effort is needed to improve husbandry Animal geneticists are asking them- and disease control practices. selves if the highly developed breeds 566 THE YEARBOOK OF AGRICULTURE 1964 and strains of livestock can be im- ditions it should take only 9 million. proved further. They are studying the It is generally true that thé repro- possibility that plateaus in breeding ductive insufficiency in livestock and may prevent or slow further progress. poultry is even more of a problem in They are looking for new breeding developing countries. Thus, research methods that may be used to remove to improve the reproductive rate of the plateaus or raise them higher. farm animals is a fertile field of inquiry. To learn the basic principles under- lying these problems, researchers have PROGRESS has been made in the con- turned to pilot experiments with small trol and eradication of animal diseases laboratory animals, such as mice, and in many countries, but losses from in- flour beetles and fruit flies. The scien- fectious and metabolic disorders re- tists have been delving deep into the main serious. Specialists have estimated inheritance of biochemical and physio- that as much as one-tenth of the ani- logical processés that afíect economic mal population in the United States is factors in the production of meat, eggs, lost each year from diseases. Losses milk, wool, and fur. from all causes due to disease have Physiologists have put renewed ef- been estimated to amount to at least fort into studies on the ability of live- 2 billion annually. stock to withstand stress—hot and cold In cattle, mastitis is a major, serious,- climates, sudden changes in tempera- unsolved problem, particularly in thé tures, natural resistance to diseases and dairy industry. Among other costly parasites, and even the stress of high diseases that call for more research levels of performance. are vibriosis, anaplasmosis, leptospiro- Losses connected with reproduction sis, leukosis, and chronic respiratory remain a serious barrier to greater effi- ailments of poultry. ciency. In the United States, the re- Of all the diseases of domestic ani- productive losses in beef and dairy mals, those of swine have been most cattle, sheep, swine, and poultry are neglected. Hog cholera, atrophie rhi- estimated to be 1.3 billion dollars each nitis, enteritis, and erysipelas are year. Many of these losses are hidden. plagues still. Swine flu, virus pneu- Techniques of artificial insemination monia, and pleuropneumonia-like in- and procedures in storing semen have fections demand study. been successful with cattle but have Control of parasites has always been been less successful with swine, sheep, recognized as critical to successful and poultry. The preservation of ova animal husbandry in the Tropics and and sperm and tissue culture methods subtropics. Its importance has been of growing animal embryos are re- underestimated in the temperate re- search fields of great potential value gions, however, except in regard to a and deserve greatly increased effort. few of the more aggressive species. With dairy cattle, about 25 percent Successful research on insect control of the cows are replaced each year, 20 has made a great contribution to the percent of which left herds because of eflficiency—or, indeed, the existence— reproductive problems.