The first wild animal to be domesticated was not a cow or a sheep, but the dog, a half-wild scavenger that may have been tolerated by early human groups as a killer of vermin and a fellow pack hunter. This partnership began before the Neolithic Revolution, predating the farming of the first crops by thousands of years. While dogs joined the human pack, the process of domesticating prey animals like sheep, goats, pigs, and cattle was a gradual evolution that occurred in different places at different times. Sheep and goats accompanied nomads across the Middle East, providing a reliable food source when hunting failed, while cattle and pigs were associated with more settled communities. The first cattle were domesticated from wild aurochs in areas that are now modern Turkey and Pakistan around 8,500 BC, offering villagers a dual advantage: a surplus of milk beyond what their calves needed and the physical strength to pull ploughs and sledges. By 4,000 BC, draught animals were increasing agricultural production immeasurably, transforming the human relationship with the land. In southern Asia, the elephant was domesticated by 6,000 BC, and in South America, llamas and alpacas were tamed before 3,000 BC to serve as beasts of burden, though they lacked the strength to pull ploughs, which limited agricultural development in the New World. The domestication of the horse began around 3,000 BC in the Black Sea and Caspian Sea region, evolving from a source of meat to a primary tool for riding and transport, while the wild ass was tamed in Egypt and camels became the beasts of burden that linked India with Mesopotamia and the Mediterranean by 1000 BC.
Ancient Civilizations and Medieval Recovery
In ancient Egypt, cattle were the most important livestock, but the agricultural landscape was rich with diversity, including sheep, goats, pigs, and poultry such as ducks, geese, and pigeons that were captured in nets and force-fed with dough to fatten them. The Nile provided a plentiful source of fish, and honey bees were domesticated from at least the Old Kingdom, providing both honey and wax for the civilization. By the first century BC, rabbits were domesticated for food in ancient Rome, and the polecat was tamed as the ferret to flush them out from their burrows, a practice described by Pliny the Elder. When the Roman empire collapsed, animal husbandry in northern Europe went into decline, but by the 11th century, the economy had recovered and the countryside was productive once more. The Domesday Book of 1086 recorded every parcel of land and every animal in England, noting that not even an ox, cow, or swine was left unrecorded. The royal manor of Earley in Berkshire, for instance, had fisheries worth 7 shillings and 6 pence each year, 20 acres of meadow, and woodland for feeding 70 pigs. Improvements in the medieval period went hand in hand with other developments, such as the plough being tilled to a greater depth and horses taking over from oxen as the main providers of traction. New ideas on crop rotation and the growing of crops for winter fodder gained ground, with peas, beans, and vetches increasing soil fertility through nitrogen fixation, allowing more livestock to be kept and creating a more robust agricultural system.
Selective breeding for desired traits was established as a scientific practice by Robert Bakewell during the British Agricultural Revolution of the 18th century, marking a shift from traditional methods to a calculated approach to agriculture. One of his most important breeding programs was with sheep, where he used native stock to quickly select for large, yet fine-boned sheep with long, lustrous wool, creating the Lincoln Longwool. This breed was then used to develop the subsequent New or Dishley Leicester, which was hornless and had a square, meaty body with straight top lines, and these sheep were exported widely to contribute to numerous modern breeds. Under Bakewell's influence, English farmers began to breed cattle for use primarily as beef, crossing long-horned heifers with the Westmoreland bull to create the Dishley Longhorn. This era of improvement saw the semi-natural, unfertilized pastures managed by grazing and mowing, a strategy that shared many beneficial characteristics with natural habitats, including the promotion of biodiversity. However, this traditional system is declining in Europe today due to the intensification of agriculture, where mechanized and chemical methods are causing biodiversity to decline. The selective breeding of the 18th century laid the groundwork for the massive productivity increases seen in the modern era, where a typical broiler chicken at eight weeks old in 2007 was 4.8 times as heavy as a bird of similar age in 1957, and the average milk yield of a dairy cow in the United States nearly doubled in the thirty years to 2007.
The Extensive and Intensive Divide
Traditionally, animal husbandry was part of the subsistence farmer's way of life, producing not only food but also fuel, fertilizer, clothing, transport, and draught power, with the killing of the animal for food being a secondary consideration. In the traditional system of transhumance, people and livestock moved seasonally between fixed summer and winter pastures, with summer pastures located in the mountains and winter pastures in the valleys. At the other extreme, in the more developed parts of the world, animals are often intensively managed, with dairy cows kept in zero-grazing conditions where all forage is brought to them, and beef cattle kept in high-density feedlots. Pigs may be housed in climate-controlled buildings and never go outdoors, while poultry may be reared in barns and kept in cages as laying birds under lighting-controlled conditions. In between these two extremes are semi-intensive, often family-run farms where livestock graze outside for much of the year, and silage or hay is made to cover the times when grass stops growing. Extensively reared animals may subsist entirely on forage, but more intensively kept livestock require energy and protein-rich foods in addition, derived from cereals, fats, oils, and sugar-rich foods. Pigs and poultry, being non-ruminants, cannot digest the cellulose in grass and are fed entirely on cereals and other high-energy foodstuffs, with ingredients that can be grown on the farm or bought in the form of pelleted or cubed compound foodstuffs specially formulated for different classes of livestock.
The Hidden Costs of Production
Animal husbandry has a significant impact on the world environment, driving climate change, ocean acidification, and biodiversity loss while killing 60 billion animals annually. Since 1950, meat production has tripled, whereas the production of dairy products doubled and that of eggs almost increased fourfold, with meat consumption nearly doubling worldwide. Developing countries have seen a surge in meat consumption, particularly of monogastric livestock, and animal husbandry uses between 20 and 33 percent of the world's fresh water. Livestock and the production of feed for them occupy about a third of the Earth's ice-free land, and some 70 percent of the agricultural land and 30 percent of Earth's land surface is involved directly or indirectly in animal husbandry. Habitat is destroyed by clearing forests and converting land to grow feed crops and for grazing, with animal husbandry causing up to 91 percent of the deforestation in the Amazon region. Cows produce some 570 million cubic metres of methane per day, accounting for 35 to 40 percent of the overall methane emissions of the planet, and livestock production is responsible for 65 percent of all human-related emissions of nitrous oxide. The primary driver of the Holocene extinction, animal husbandry kills 60 billion animals annually and contributes to species extinction, desertification, and habitat destruction.
The Welfare and Cultural Paradox
Since the 18th century, people have become increasingly concerned about the welfare of farm animals, with standards and laws created worldwide based on a form of utilitarianism that it is morally acceptable to use non-human animals provided no unnecessary suffering is caused. An opposing view holds that animals have rights, should not be regarded as property, and should never be used by humans, leading to the banning of live exports from New Zealand in 2003 as a result of objections to long-distance transport. The reality of animal husbandry is often distorted, softened, or idealized in books and songs for children, giving them an almost entirely fictitious account of farm life that is completely at odds with the impersonal, mechanized activities involved in modern intensive farming. Pigs appear in several of Beatrix Potter's little books and as Piglet in A.A. Milne's Winnie the Pooh stories, yet they are also depicted somewhat more darkly as Babe in Dick King-Smith's The Sheep-Pig and as Wilbur in E.B. White's Charlotte's Web. Many of these books are completely anthropomorphic, dressing farm animals in clothes and having them walk on two legs, live in houses, and perform human activities. Many urban children experience animal husbandry for the first time at a petting farm, but this presents some risk of infection, as a strain of E. coli infected 93 people who had visited a British interactive farm in an outbreak in 2009, highlighting the gap between the romanticized image of farming and its biological realities.
The Global Spectrum of Livestock
There is no single universally agreed definition of which species are livestock, but widely agreed types include cattle for beef and dairy, sheep, goats, pigs, and poultry, while various other species such as horses, buffalo, and the South American camelids like the alpaca and llama are sometimes considered livestock. In some parts of the world, livestock includes species such as fish in aquaculture, micro-livestock such as rabbits and rodents like guinea pigs, as well as insects from honey bees to crickets raised for human consumption. Bees have been kept in hives since at least the First Dynasty of Egypt, five thousand years ago, and fixed comb hives are used in many parts of the world, while in more advanced economies, modern strains of domestic bee have been selected for docility and productiveness. Sericulture, the rearing of silkworms, was first adopted by the Chinese during the Shang dynasty, with the only species farmed commercially being the domesticated silkmoth, which produces an exceedingly long, slender thread of silk when it spins its cocoon. In Thailand, crickets are farmed for human consumption in the north of the country, and palm weevil larvae in the south, while the bamboo caterpillar is another delicacy of this region. Fish and prawns can be cultivated in rice paddies, either arriving naturally or being introduced, and both crops can be harvested together, demonstrating the diverse and often unexpected ways in which animals are integrated into human food systems.