25/11/2021
Although all mammals produce milk to nourish their young, the cow is predominantly used throughout the world to produce milk and milk products for human consumption. Other animals used to a lesser extent for this purpose include sheep, goats, camels, buffaloes, yaks, reindeer, horses and donkeys.[57]
All these animals have been domesticated over the centuries, being bred for such desirable characteristics as fecundity, productivity, docility and the ability to thrive under the prevailing conditions. Whereas in the past, cattle had multiple functions, modern dairy cow breeding has resulted in specialised Holstein Friesian-type animals that produce large quantities of milk economically. Artificial insemination is widely available to allow farmers to select for the particular traits that suit their circumstances.[58]
Whereas in the past, cows were kept in small herds on family farms, grazing pastures and being fed hay in winter, nowadays there is a trend towards larger herds, more intensive systems, the feeding of silage and "zero grazing", a system where grass is cut and brought to the cow, which is housed year-round.[59]
In many communities, milk production is only part of the purpose of keeping an animal which may also be used as a beast of burden or to draw a plough, or for the production of fibre, meat and leather, with the dung being used for fuel or for the improvement of soil fertility. Sheep and goats may be favoured for dairy production in climates and conditions that do not suit dairy cows.[57]
Meat
Hereford cow
The Hereford is a hardy breed of beef cattle, now raised in many countries around the world.
Main articles: Meat industry, Cattle, Sheep farming, Pig farming, and Cuniculture
Meat, mainly from farmed animals, is a major source of dietary protein around the world, averaging about 8% of man's energy intake. The actual types eaten depend on local preferences, availability, cost and other factors, with cattle, sheep, pigs and goats being the main species involved. Cattle generally produce a single offspring annually which takes more than a year to mature; sheep and goats often have twins and these are ready for slaughter in less than a year; pigs are more prolific, producing more than one litter of up to about 11[60] piglets each year.[61] Horses, donkeys, deer, buffalo, llamas, alpacas, guanacos and vicunas are farmed for meat in various regions. Some desirable traits of animals raised for meat include fecundity, hardiness, fast growth rate, ease of management and high food conversion efficiency. About half of the world's meat is produced from animals grazing on open ranges or on enclosed pastures, the other half being produced intensively in various factory-farming systems; these are mostly cows, pigs or poultry, and often reared indoors, typically at high densities.[62]
Poultry
Battery hens
Battery hens, Brazil
Main article: Poultry farming
Poultry, kept for their eggs and for their meat, include chickens, turkeys, geese and ducks. The great majority of laying birds used for egg production are chickens. Methods for keeping layers range from free-range systems, where the birds can roam as they will but are housed at night for their own protection, through semi-intensive systems where they are housed in barns and have perches, litter and some freedom of movement, to intensive systems where they are kept in cages. The battery cages are arranged in long rows in multiple tiers, with external feeders, drinkers, and egg collection facilities. This is the most labour saving and economical method of egg production but has been criticised on animal welfare grounds as the birds are unable to exhibit their normal behaviours.[63]
In the developed world, the majority of the poultry reared for meat is raised indoors in big sheds, with automated equipment under environmentally controlled conditions. Chickens raised in this way are known as broilers, and genetic improvements have meant that they can be grown to slaughter weight within six or seven weeks of hatching. Newly hatched chicks are restricted to a small area and given supplementary heating. Litter on the floor absorbs the droppings and the area occupied is expanded as they grow. Feed and water is supplied automatically and the lighting is controlled. The birds may be harvested on several occasions or the whole shed may be cleared at one time.[64]
A similar rearing system is usually used for turkeys, which are less hardy than chickens, but they take longer to grow and are often moved on to separate fattening units to finish.[65] Ducks are particularly popular in Asia and Australia and can be killed at seven weeks under commercial conditions.[66]
Aquaculture
Freshwater fish farm
Freshwater fish farming, France
Main article: Aquaculture
Aquaculture has been defined as "the farming of aquatic organisms including fish, molluscs, crustaceans and aquatic plants and implies some form of intervention in the rearing process to enhance production, such as regular stocking, feeding, protection from predators, etc. Farming also implies individual or corporate ownership of the stock being cultivated."[67] In practice it can take place in the sea or in freshwater, and be extensive or intensive. Whole bays, lakes or ponds may be devoted to aquaculture, or the farmed animal may be retained in cages (fish), artificial reefs, racks or strings (shellfish). Fish and prawns can be cultivated in rice paddies, either arriving naturally or being introduced, and both crops can be harvested together.[68]
Fish hatcheries provide larval and juvenile fish, crustaceans and shellfish, for use in aquaculture systems. When large enough these are transferred to growing-on tanks and sold to fish farms to reach harvest size. Some species that are commonly raised in hatcheries include shrimps, prawns, salmon, tilapia, oysters and scallops. Similar facilities can be used to raise species with conservation needs to be released into the wild, or game fish for restocking waterways. Important aspects of husbandry at these early stages include selection of breeding stock, control of water quality and nutrition. In the wild, there is a massive amount of mortality at the nursery stage; farmers seek to minimise this while at the same time maximising growth rates.[69]
Insects
Crickets
Crickets being raised for human consumption, Thailand
Further information: Beekeeping, Entomophagy, Insect farming, and Sericulture
Bees have been kept in hives since at least the First Dynasty of Egypt, five thousand years ago,[70] and man had been harvesting honey from the wild long before that. Fixed comb hives are used in many parts of the world and are made from any locally available material.[71] In more advanced economies, where modern strains of domestic bee have been selected for docility and productiveness, various designs of hive are used which enable the combs to be removed for processing and extraction of honey. Quite apart from the honey and wax they produce, honey bees are important pollinators of crops and wild plants, and in many places hives are transported around the countryside to assist in pollination.[72]
Sericulture, the rearing of silkworms, was first adopted by the Chinese during the Shang dynasty.[73] The only species farmed commercially is the domesticated silkmoth. When it spins its cocoon, each larva produces an exceedingly long, slender thread of silk. The larvae feed on mulberry leaves and in Europe, only one generation is normally raised each year as this is a deciduous tree. In China, Korea and Japan however, two generations are normal, and in the tropics, multiple generations are expected. Most production of silk occurs in the Far East, with a synthetic diet being used to rear the silkworms in Japan.[74]
Insects form part of the human diet in many cultures.[75] In Thailand, crickets are farmed for this purpose in the north of the country, and palm weevil larvae in the south. The crickets are kept in pens, boxes or drawers and fed on commercial pelleted poultry food, while the palm weevil larvae live on cabbage palm and sago palm trees, which limits their production to areas where these trees grow.[76] Another delicacy of this region is the bamboo caterpillar, and the best rearing and harvesting techniques in semi-natural habitats are being studied.[76]
Effects
Environmental impact
Main articles: Environmental impact of livestock and Environmental impact of meat production
Cattle
Livestock production requires large areas of land.
Animal husbandry has a significant impact on the world environment. Being a part of the animal–industrial complex, animal agriculture is the primary driver of climate change, ocean acidification, biodiversity loss, and of the crossing of almost every other planetary boundary, in addition to killing more than 60 billion non-human land animals annually.[77] It is responsible for somewhere between 20 and 33% of the fresh water usage in the world,[78] and livestock, and the production of feed for them, occupy about a third of the earth's ice-free land.[79] Livestock production is a contributing factor in species extinction, desertification,[80] and habitat destruction.[81] Animal agriculture contributes to species extinction in various ways and is the primary driver of the Holocene extinction.[82][83][84][85][86] Habitat is destroyed by clearing forests and converting land to grow feed crops and for animal grazing, while predators and herbivores are frequently targeted and hunted because of a perceived threat to livestock profits; for example, animal husbandry is responsible for up to 91% of the deforestation in the Amazon region.[87] In addition, livestock produce greenhouse gases. Cows produce some 570 million cubic metres of methane per day,[88] that accounts for from 35 to 40% of the overall methane emissions of the planet.[89] Livestock is responsible for 65% of all human-related emissions of the powerful and long-lived greenhouse gas nitrous oxide.[89]
As a result, ways of mitigating animal husbandry's environmental impact are being studied. Strategies include using biogas from manure,[90] genetic selection,[91][92] immunization, rumen defaunation, outcompetition of methanogenic archaea with acetogens,[93] introduction of methanotrophic bacteria into the rumen,[94][95] diet modification and grazing management, among others.[96][97][98] A diet change (with Asparagopsis taxiformis) allowed for a reduction of up to 99% of methane production in an experimental study with three ruminants.[99][100]
Animal welfare
Main article: Animal welfare
Since the 18th century, people have become increasingly concerned about the welfare of farm animals. Possible measures of welfare include longevity, behavior, physiology, reproduction, freedom from disease, and freedom from immunosuppression. Standards and laws for animal welfare have been created worldwide, broadly in line with the most widely held position in the western world, a form of utilitarianism: that it is morally acceptable for humans to use non-human animals, provided that no unnecessary suffering is caused, and that the benefits to humans outweigh the costs to the livestock. An opposing view is that animals have rights, should not be regarded as property, are not necessary to use, and should never be used by humans.[101][102][103][104][105] Live export of animals has risen to meet increased global demand for livestock such as in the Middle East. Animal rights activists have objected to long-distance transport of animals; one result was the banning of live exports from New Zealand in 2003.[106]
David Nibert, professor of sociology at Wittenberg University, posits that, based on contemporary scholarship by ethologists and biologists about the sentience and intelligence of other animals, "we can assume that, for the most part, the other animals' experience of capture, enslavement, use, and slaying was one of suffering and violence." Much of this involved direct physical violence, but also structural violence as their systemic oppression and enslavement "resulted in their inability to meet their basic needs, the loss of self-determination, and the loss of opportunity to live in a natural way." He says that the remains of domesticated animals from thousands of years ago found during archeological excavations revealed numerous bone pathologies, which provide evidence of extreme suffering:
Excavations from 8500 BCE revealed bone deformities in enslaved goats and cows and provided "some indication of stress, presumably due to the conditions in which these early domestic animals were kept." Remains of sheep and goats from the early Bronze Age show a marked decrease in bone thickness, reflecting calcium deficiencies "resulting from the combined effects of poor nutrition and intensive milking."[107]
In culture
Cartoon of John Bull giving his breeches to save his bacon
Opening of the budget; – or – John Bull giving his breeches to save his bacon[note 1] by James Gillray (d. 1815)
Since the 18th century, the farmer John Bull has represented English national identity, first in John Arbuthnot's political satires, and soon afterwards in cartoons by James Gillray and others including John Tenniel. He likes food, beer, dogs, horses, and country sports; he is practical and down to earth, and anti-intellectual.[108]
Farm animals are widespread in books and songs for children; the reality of animal husbandry is often distorted, softened, or idealized, giving children an almost entirely fictitious account of farm life. The books often depict happy animals free to roam in attractive countryside, a picture completely at odds with the realities of the impersonal, mechanized activities involved in modern intensive farming.[109]
Illustration of dressed pigs
Dressed pigs in Beatrix Potter's 1913 The Tale of Pigling Bland
Pigs, for example, appear in several of Beatrix Potter's "little books", as Piglet in A.A. Milne's Winnie the Pooh stories, and somewhat more darkly (with a hint of animals going to slaughter) as Babe in Dick King-Smith's The Sheep-Pig, and as Wilbur in E. B. White's Charlotte's Web.[110] Pigs tend to be "bearers of cheerfulness, good humour and innocence". 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.[109] The children's song "Old MacDonald Had a Farm" describes a farmer named MacDonald and the various animals he keeps, celebrating the noises they each make.[111]
Many urban children experience animal husbandry for the first time at a petting farm; in Britain, some five million people a year visit a farm of some kind. This presents some risk of infection, especially if children handle animals and then fail to wash their hands; a strain of E. coli infected 93 people who had visited a British interactive farm in an outbreak in 2009.[112] Historic farms such as those in the United States offer farmstays and "a carefully curated version of farming to those willing to pay for it",[113] sometimes giving visitors a romanticised image of a pastoral idyll from an unspecified time in the pre-industrial past.