|
|
Animal Husbandry, the breeding, feeding, and management of animals for the production of food, fibre, work, and pleasure. Modern methods concentrate on one type of animal in large, efficient farming units that generate animal products at the highest rate of return for investment. Intensive husbandry conditions include large numbers of animals in small pens or cages, enriched feed, growth stimulation by various means, and vaccination against disease. Most of the world's domestic animals, however, are raised in small units under less efficient conditions and at lower rates of return.
Animals furnish about 28 per cent of the world's total value of agricultural products. They supply a much higher proportion of human food in the developed countries than elsewhere.
Traditional husbandry practices are closely associated with the degree of control needed over the animals that are kept and with the uses to which they are put. Most domesticated animals have multiple uses; for example, animals kept primarily for work also supply milk, meat, and clothing materials. The animals and their uses, however, are closely associated with the culture and experience of the people who care for them (see Agriculture). In some regions of the world, cattle are not used in the production of food. Studies have shown that the work power, fertilizer, milk, and the fuel from dung that the cattle provide in these regions are more efficient animal products than meat. Analysis of other cultural practices has often revealed that animals are put to unexpectedly efficient use according to local circumstances.
Environmental influences such as climate also play an important role in the domestication and use of animals. Water buffaloes are used as draught animals in southern Asia, where they have adapted to the high temperatures and humidity, whereas horses, which thrive in moderate climates, were the principal draught animals in the temperate regions until they were replaced by tractors. Cattle from India that are acclimatized to hot and humid conditions are prevalent in the southern United States because they are better adapted to the climate of the region than are European cattle.
Draught Animals
Domesticated animals used primarily for work, transport, and leisure are widely distributed. They include the horse, mule, donkey (or ass), ox, buffalo, camel, llama, alpaca, yak, reindeer, and dog.
Modern horses are thought to have descended from one or more of three subspecies, including the tarpan, Przhevalski's horse, and the European forest horse. They are still used for draught, that is for pulling heavy loads, in many countries of the world. They are also used for controlling other types of animals, for carrying packs, and for riding for leisure and sport. The world population of horses is estimated at more than 60 million; approximately half are in North and South America and half in Asia and Europe. The 12 million or so mules in the world are fairly evenly divided among Africa, North and Central America, and South America. Of the 40 million or more donkeys, about half are in Asia and a quarter in Africa.
Camels, llamas, and alpacas are used as beasts of burden. Of the 17 million or so camels in the world, approximately three-quarters are found in Africa and the rest in Asia. The llama and alpaca are mostly limited to small areas in South America. Practically all water buffaloes are found in Asia, and are used primarily as draught animals, although they have potential for the production of milk and meat. Oxen are also important draught animals in Asia and in some parts of south-eastern Europe. Dogs are used as pack animals in Alaska and Siberia and are also used to control sheep and other animal herds.
Sheep and Goats
Sheep are used for wool, meat (mutton and lamb), and to a small extent for milk. They are commonly divided into three types based on whether their wool is fine, medium, or coarse. Perhaps the first animals to be used in husbandry, they were domesticated in south-western Asia about 11,000 years ago, and approximately a billion are now widely distributed throughout the world, with the largest populations in Africa, South America, Asia, Europe, and Oceania. Commercial sheep farming is usually conducted on large tracts of land, divided into operational units containing 1,000 or more animals per unit. Sheep are also raised as a secondary enterprise on many small farms. They are well adapted to semi-arid regions and to land that is too steep or rough for the cultivation of crops.
Goats were first domesticated in the same region as sheep, and for the same uses, but 1,500 or so years later. They are about two-fifths as numerous as sheep and show a similar distribution pattern.
Pigs
Recent evidence suggests that pigs were domesticated about 9,000 years ago in several world regions simultaneously. Worldwide, there are now estimated to be more than 700 million. Approximately half are raised in Asia, primarily in China, Europe, Russia, and South America also have large numbers. Unlike most domestic animals, pigs are omnivorous and compete directly with humans for many foods.
Cattle
Modern cattle are usually divided into three types: beef, dairy, and dual purpose, an intermediate type used for both milk and meat. It is believed that cattle were domesticated about 8,500 years ago in south-eastern Europe, with South East Asia a probable second centre of domestication. World cattle population is more than 1 billion, with half concentrated in South America, Europe, Russia, the United States, and India. Most beef cattle are raised on large tracts of land, but, following weaning, the young animals to be used for meat may be fattened in pens. Dairy cattle are managed in relatively large herds under intensive conditions near centres of dense population. Cheese, dried milk, and other specialized products, however, usually come from small farms with cows set out to pasture. See Dairy Farming.
Poultry
The term poultry mainly covers chickens, ducks, turkeys, geese, guinea fowl, and squabs. Each of these domesticated groups is descended from a closely related wild bird and was probably first developed in the areas where the wild bird was indigenous. World numbers are estimated at more than 6 billion chickens, with somewhat more than 100 million ducks and slightly fewer than 100 million turkeys. Estimates for other types are not available. Chickens are numerous in most regions of the world, while most ducks are produced in Europe and Asia, and most turkeys in the United States. In the developed countries, production units for meat and eggs are large and intensive, with individual birds housed singly in cages or housed together in large numbers. See Also Battery Farming; Poultry Farming.
Other Animals
Other domesticated animals of importance include, in the cattle family, the yak in Tibet, the mithan in India, and the banteng in South East Asia. The reindeer is important in the northern regions of Europe and northern Asia.
Although a few specialized farms have raised various animals (primarily mink and foxes) for their pelts, most furs are obtained from wild animals by hunting and trapping. In North America, muskrats and raccoons provide slightly more than half the total revenue. The former Union of Soviet Socialist Republics (USSR) was also a leading fur nation. See Fur Industry.
Current Trends
The major concern of animal husbandry today is the extent to which production can be maintained as the human population increases. The goal of research has been to increase the efficiency of the production of animal products by genetic selection and genetic engineering. For example, scientists have increased the size of sheep by inserting growth-hormone genes into embryos, and the same method can be applied to cattle and other animals.
Research is also being directed towards the development of animal strains in areas deficient in protein. Thus in South America the capybara is being utilized by Venezuela for its meat; it is taken from the wild in large numbers to lands devoted to cattle raising. In Peru, the government is encouraging the raising of guinea pigs for their food value, and elsewhere in Latin America research is being conducted into the farming of the iguana lizard.
Intensive methods for producing animal products include confinement of poultry in small cages, pigs in small pens, and sheep and cattle in small lots. Confinement leads to savings in labour, feed, and other production costs. Confinement in individual pens may also afford savings from improved disease control and better protection from predators. Such practices have been condemned as being cruel to the animals, and protective legislation has been advocated. Livestock and poultry farmers, on the other hand, argue that the animals are probably not under much stress because disturbed animals usually show sharp decreases in productive capacity.
Also at issue is the use of special additives, including hormones, antibiotics, vitamins, and other substances to increase growth or productivity. General guidelines state that any supplement must be proved safe and effective in the amounts used. The two most controversial growth additives are the hormone diethylstilbestrol (DES) and antibiotics. DES is now banned because in high doses it was found to be capable of causing cancer. Scientists who advocate the banning of antibiotics argue that resistant strains of bacteria in animals might transfer their resistance to bacteria that infect humans. The physiological limits of all domestic animals may eventually prevent further increases in yield. If the human population continues to expand and food supplies become scarcer, the proportion of food that can be used to feed animals will then decrease, and animal products will be in shorter supply and more expensive.
