Feeding of Farm Animals

(1) One of the most important production processes in livestock raising, in which feeds of plant and animal origin are used to obtain livestock products. (2) A branch of the science of livestock management that studies the scientific principles and methods of proper feeding of farm animals to ensure their normal growth, development, and high productivity and to improve existing breeds and develop new ones. The principal problems studied are analysis of animals’ food requirements, establishment of the nutritive value of feeds, the setting of feeding standards, preparation of feed rations, and development of correct techniques and organization of feeding.

Pasture grasses served as the only fodder for domestic animals in the period of nomad livestock raising. With the transition to settled livestock raising and development of agriculture, animals were housed in sheds, fodder was stored for winter, and livestock was fed agricultural wastes. The expansion of industry and development of industrial centers sharply increased the need for livestock products, so that more attention was given to organizing the feeding and management of livestock. The wastes of industries processing agricultural products began to be used as feed. Practical needs stimulated the development of theories of feeding farm animals, based on advances in biology, physiology, chemistry, physics, and other sciences and on the experience of livestock raisers. Theories on the nutritive value of feed were developed in the early 19th century. The German scientist A. Thaer was the first to calculate the food requirements of farm animals in terms of uniform standards. Feeding standards were based on empirical data. From the mid-19th century the nutritive value of feeds and feeding standards were established on the basis of information about the chemical composition of feeds. In the 1860’s the German scientist E. Wolff proposed a system of evaluating feeds and standardizing feeding according to digestible substances. Research disclosed the value of various nutrients for animals. The French scientist F. Magendie (1816) was the first to study the function of protein.

In Russia in 1872, A. Rubets studied the mineral requirements of animals, and in 1880, N. I. Lunin demonstrated the presence in foods of substances that were later (1912) called vitamins. N. P. Chirvinskii studied qualitative transformations of substances in animals, proving (1881) that fat could be formed from carbohydrates. In 1909, E. A. Bogdanov showed that fat could be formed from the protein in feed. The research of V. V. Pashutin and his students at the end of the 19th century and in the early 20th century provided the theoretical basis for the study of metabolism in animals. They developed a technique for calculating the balance of substances and energy in animals and improved the methods of performing scientific experiments with animals. All these achievements led to the development of methods of assessing the nutritive value of feeds and standardizing the feeding of animals according to the fattening capacity of feeds. The German scientist O. Kellner proposed the starch equivalent as a unit of nutritive value, and the American scientist H. Armsby introduced the therm as a feed unit. N. Fjord in Denmark and N. Hansson in Sweden developed the Scandinavian feed unit. The Soviet feed unit was adopted in the USSR on the recommendation of E. A. Bogdanov. M. F. Ivanov, M. I. D’iakonov, E. F. Liskun, and I. S. Popov studied the feed resources of the USSR. The first complete table of the chemical composition and nutritive value of feeds in different regions was prepared in 1933. Scientific principles were worked out for feeding animals according to species, breed, sex, age, physiological condition (pregnancy, lactation, fattening), type of use, and level of productivity. Feeding standards were established on the basis of data on animal food requirements obtained in institutes and at experiment stations between 1930 and 1935. These standards were subsequently made more specific and perfected and more indicators were standardized. The standardization of feeding, which permitted control of feed consumption and more effective use of feed, became the basis for the planning of livestock breeding.

In the mid-20th century the work of scientists in many countries contributed to the development of the concept of balanced feeding of farm animals. Optimal feed requirements were established for animals according to type, age, condition, and economic use. The effect of daily management and routine on the appetite of animals was clarified, and the significance of the number of daily feedings was studied. The influence of the physical state of feeds (moisture content, degree of mincing) was determined, contributing to the development and use of such new types of feed as grass meal, haylage, and granules. Recommendations were made for the most economical feeding of animals in different regions.

The energy value of various feeds is being studied. The caloric content of feeds has been determined so that feeding can be standardized according to their energy value. Much attention is devoted to protein nutrition and animals’ protein requirements, to the possibility of using nonprotein nitrogen, to increasing the biological value of protein, to the amino acid composition of proteins, to the role of amino acids in animal nutrition, to the methods of balancing rations according to the amino acid composition of feeds, to mineral nutrition, and to the importance of macronutrients and trace elements for livestock raising in different biogeochemical zones and regions. After the function of vitamins and significance of vitamin nutrition were established, it was possible to develop agents for the prevention and treatment of many avitaminoses and hypovitaminoses.

A variety of stimulants, including antibiotics, enzymes, hormones, and various sera and tissue preparations, are now used in feeding farm animals. All these agents affect metabolism, the digestive processes, and the digestibility and utilization of nutrients. They accelerate growth and development and increase the animals’ productivity and fertility.

Scientific organizations are working on formulas for complete mixed feeds, mixed-feed concentrates, whole milk substitutes, premixes, and other supplements. The mixed-feed industry is producing feed mixtures according to these formulas. The chemical industry is manufacturing carbamide-ammonium salts, synthetic lysine, methionine, tryptophan, and other amino acids, as well as vitamins, mineral supplements, and preservatives. The hydrolysis industry is producing feed yeasts. Old methods are being improved and new ones introduced for procuring, preserving, and storing fodders, including ensilage, making haylage, chemical preservation, rapid drying of grass by ventilation, briquetting, and granulation. Improvements have also been introduced in the methods for preparing feeds by grinding, treatment with chemicals, scalding, and fermentation. Many processes of feed production, preparation, and distribution have been mechanized. Modern mathematical methods and computer technology have helped solve many problems connected with the preparation of feed schedules, rations, and mixed-feed formulas.

Since the cost of feeds constitutes a substantial part (50-75 percent) of the total cost of livestock products, the use of advances in science and practical experience is a major factor in reducing production expenses.

Modern methods of large-scale livestock raising require feeding techniques ensuring optimal functioning of animals’ metabolic processes in order to achieve a still more rapid increase in productivity and more efficient use of feed. Many scientific organizations are conducting research on these problems. The feeding of farm animals is taught as a course in agricultural and livestock management institutes and technicums.