2  Domestication of Farm Animals

This chapter contains lots of quantitative data - such as carcass weights and dressing percentages. They give you an idea of the sizes involved.  It is worth remembering the approximations but not the details.  The details change with different sources.

2.1 Origins of beef

Beef - more than one species. In the developed countries, beef is mostly produced from cattle of the genus Bos.  However, there are several other genera  which will interbreed with Bos to produce fertile, beefy offspring: Bison;  Poephagus, the yak; Bibos, the gaurs; Bubalus, the Indian buffalo; Sunda; and Syncerus, the African buffalo.

In Canada, our interest is in the main evolutionary steps from Bos primigenius (wild cattle of ancient Europe, now extinct), to Bos longifrons (the first domesticated cattle leaving fossils found in archaeological excavations), to Bos taurus (modern cattle).

In the tropics, there may have been another sequence, from Bos nomadicus (wild ancestors)  to Bos indicus (current heat-resistant cattle).  B. indicus, which may have been derived from B. nomadicus, is now recognized by the following features: a prominent shoulder hump of muscle supported by dorsal spines of the vertebrae, a long face with drooping ears, upright horns, small brow ridges, a prominent dewlap, slender legs, and uniform colouration (white, grey or black).

Sketch of Bos primigenius - the Aurochs (plural aurochsen) - a butcher's nightmare - vicious horns and tough meat.


Migrations and mixing.  In North America, cattle were introduced by Spanish settlers to the Southwest USA, giving rise to breeds such as the Texas Longhorn.  But in the north, the cattle were mainly derived from primitive breeds brought by French and British settlers.  Bos primigenius genes were probably carried by the Spanish cattle while the primitive northern breeds were probably a mixture of B. primigenius and B. longifrons.  In early settlements, the primary importance of cattle was their ability to pull a plough or a cart, and they were not normally slaughtered until the end of their working life. Improved British breeds of cattle developed in the late 1700s and 1800s were imported into North America to form the basic Shorthorn, Angus, and Hereford stock.  Between 1905 and 1920, Bos indicus (Brahman cattle from India) was introduced into the southern USA for its heat tolerance.  The most recent phase of beef breed development in North America has been a re-introduction of Continental European beef breeds with rapid early growth and a large mature frame size - animals preserved as draft animals where steam engines were scarce. The large size of some of these breeds suggests they may contain genes derived from Bos primigenius. There is renewed interest in early maturing breeds, such as Angus, because of their ability to produce fine-grained, tender beef.  Whether or not these features will survive the current selection practices in favour of rapid early growth and a large mature frame remains to be seen.

Bison. The bison (Bison bison), known as the buffalo in American folklore, was nearly hunted to extinction but now is protected and ranched. Ranch bison is sold commercially. The traditional prime parts were the tongue and the hump, but steaks and burgers are now the main commodity. Bulls can reach a massive size, around 1,000 kg live weight, but commercial meat is from smaller animals.  After being on a finishing ration to a slaughter age of 14 to 15 months, carcasses weigh around 276 and 248 kg for bulls and cows, respectively. Dressing percentages (defined in LAB 1) are about 60%, but the carcasses are light in the hindquarter. Bison meat is dark, but this does not show after cooking. Treating bison carcasses like those of beef animals, cooler shrink losses are slightly higher than those for beef, probably because of the lighter fat cover and larger area of exposed muscles. However, shrink losses from bison carcasses may be improved by blast cooling. The saleable yield of meat trimmed to retail standards is around 78% of cold carcass weight. Shear values measuring the toughness of the meat tend to have a wider range than those of beef but may be generally improved by electrical stimulation (which prevents cold-shortening, defined in LEC 13). The ultimate pH (defined in LEC 12) of bison meat is within a typical range for red meat (say pH 5.4 to 5.7). The main marketing feature of bison meat is that it tends to have a lower fat content than beef.

Buffalo.  African buffalo (Syncerus caffer) come in several sizes, ranging from the dwarf forest buffalo of West and Central Africa to the heavy Cape buffalo of South Africa. For bulls and cows, respectively, carcass weights of 380 and 326 kg have been recorded, with dressing percentages up to about 50%. 

Yak. The domesticated yak of China and Mongolia is Poephagus (also known as Bos grunniens). The wild yak may be called Bos mutus. The domesticated yak of Asia is smaller (maximum around 550 kg live weight for bulls and 350 kg for cows) than the wild yak. Yak hair is long and shaggy and is underlain by fine wool. The tail is a long brush, which is unusual for bovines. Yak meat is of secondary importance. Milk and hide products are more important.

2.2 Origins of pork

Species of pigs. Fossil pig skeletons have been found in geological deposits dating back to the Pliocene period in Europe and Asia.  Domestic pigs of Europe and North America appear to be a mixture of two original species of wild pig: Sus scrofa, the wild boar of Europe found north of the Alps, and S. vittatus, the wild pig now only found wild in the Malay Peninsula.  Wild pigs of the same genus (Sus) but of different species to domestic pigs are found in India and Ceylon (S. cristatus).  The domestic pigs now found in China are usually considered to be S. vittatus.  Whether or not S. scrofa and S. vittatus should be considered as separate species is a difficult question because transitional races are now widespread, thus demonstrating the obvious point that the hybrids are fertile.  The scientific distinction between S. scrofa and S. vittatus is based on the shape of the lacrimal bone in the skull (located round the orbit of the eye and supporting the tear duct from the eye to the nose).  Several different subspecies of wild swine are recognised: Sus scrofa scrofa, Europe; S. s. meridionalis, Mediterranean; S. s. barbarus, North Africa; S. s. attila, Eastern Asia; and  S. s. palustris, found in the archaeological excavations of Swiss Neolithic lake dwellings.

Early evidence of pork consumption. In the bone heaps around the eating areas of prehistoric peoples are found the remains of three types of pigs: bones of wild pigs obtained from hunting, bones of large pigs probably put out to forage, and bones of small pigs probably kept in confined or covered areas.  Remains of domesticated pigs are not found before Neolithic times (the agricultural revolution when man became a settled farmer) and, since pigs are difficult to control (they do not easily form herds like the ruminants), the nomadic farmers of earlier times probably did not have any pigs.  Tribal conflict between settled farmers and warlike nomads may explain why domestic pigs, the invention of the settled farmer, were first prohibited by some religions.  Another factor is the existence of parasites such as the pork tapeworm and trichinella (described in LAB 3).

Because of their rooting habits when foraging, pigs probably produced a dramatic change in the local ecology by reducing woodland undergrowth and allowing grass to grow.  Before the invention of ploughing, pigs may have been driven over seeded ground to embed the seeds.  Pigs may be used to hunt for underground mushrooms (truffles) or to retrieve game, and these habits might have been important to primitive farmers.

Breeds of pigs  In medieval times, herded pigs had a long snout and legs. Around the year 1800, Chinese pigs were introduced into Europe and combined with Sus scrofa.  This resulted in a dramatic phenotypic change as pigs became thick-set in shape, smaller in size and laid down fat earlier in life.

Early development of pig breeds was influenced by factors such as ease of taming, socially structured behaviour, large numbers of offspring at relatively short intervals, early rapid growth and maturation, and longevity.  In the 1800s, the ability of pigs to store large amounts of fat was considered a desirable feature because, before the widespread use of fossil fuel energy for industrial machines, ordinary people expended large amounts of energy in their daily work.  The high caloric content of fat and the high fat content of pork once provided important food energy.  Nowadays, however, there is intensive selection against fatness and in favour of lean muscle development. For the gourmet, however, nothing comes close to fat pork from an old-fashioned pig, especially if it is properly conditioned.

3.3 Origins of lamb

There are many different wild species and domestic breeds of sheep in five main groups;
(1), the moufflon from Mediterranean countries;
(2), urial from southern Russia;
(3), argali from the Himalayas;
(4), bighorn from Canada and eastern Russia; and
(5), domestic sheep, Ovis aries.

Sheep were domesticated at an early stage in the transition from nomad to settled farmer. Goats probably were domesticated before sheep, but the domestication of sheep precedes that of cattle and pigs.  Numerous characteristics have been changed by domestication.  Many wild types of sheep have a wool-hair mixture and, in hot climates, certain species are almost naked.  Wool bearing sheep probably were derived from animals originating in cold or mountain conditions. Domestic sheep show a range from very short to very long tails, but all wild types have short tails.  Some sheep deposit fat in their tails. The lop-eared characteristic is not found in wild sheep and was produced very early during domestication. A convex nose is a striking feature of many breeds of sheep and is associated with a decrease in length of the jaws, which is a common feature in many other domesticated animals such as the pig and dog.  Wild sheep often wield an array of elaborately shaped horns.  During domestication the number has been reduced to a single pair, or horns have been lost altogether (polled). Animals kept in arid, rocky conditions derive an advantage from long legs, while smaller sheep are better for winter housing in colder climates.

3.4 Origin of chicken

The domestic chicken is descended from the Red Jungle Fowl, Gallus gallus. Chicken is used as a generic term in some countries whereas, in others, chickens are categorised by age and type. In France, for example, the age range is from young poussin to the poule, an old fowl. Similarly, in North America, although different breeds usually become anonymous after slaughter, a series of carcass types is defined by age and size.

Rock Cornish are 4 to 5 weeks of age, their carcasses weigh less than about 0.8 kg, and they may be males or females.

Broilers or fryers are about 5 to 8 weeks of age, have carcass weights from  0.8 to 1.8 kg, and may be males or females.

Roasters are males or females older than 9 weeks with carcasses over 1.8 kg.

Capons are castrated males over 9 weeks of age and with carcasses over 1.8 kg. Surgical castration is difficult (because the male gonads are inside the body cavity near the kidneys, as described in LAB 4) and has been replaced by hormonal castration in most countries.

Chicken carcasses with tender meat may be identified by their soft, pliable and smooth‑textured skin, and by their flexible sternal cartilage. Chickens such as roosters and mature hens producing relatively tough meat are identified by their greater age, coarse skin, and stiff sternal cartilage. Several features may be used as a guide to the age of a chicken. Young birds have unwrinkled combs with sharp points. In older birds, the comb becomes wrinkled with blunt points. The plumage becomes worn and faded in older birds, unless the birds have just moulted. With age, the subcutaneous fat becomes darker and lumped under the main feather tracts, and the pelvic bones become less pliable. Old chickens have large scales which are rough and slightly raised and their oil sac becomes enlarged and hardened. Older male chickens develop long spurs.

3.4 Origin of ducks

Study hint.  The scientific names for the species of the wild ducks are for the hunters and bird-watchers! No need to learn them.

Wild versus domestic ducks. Ducks, geese and swans are grouped together in the Order Anseriformes. Ducks comprise the Family Anatidae. Ducks are poor walkers but good swimmers, which means their legs are set far back in the body and are well muscled. Ducks are hunted extensively for their meat. The main types are the surface-feeding ducks such as the wild mallard (Anas platyrhynchos),  teal and widgeon (Mareca americana); the diving ducks such as the redhead (Aythya americana), canvasback (Aythya valisineria) and ring-necked duck (Aythya collaris); the sea ducks, which seldom provide meat with a pleasant taste; stiff-tailed ducks such as the ruddy duck (Oxyura jamaicensis); and the mergansers, whose meat is seldom palatable.


Thus, wild ducks produce meat with a wide range from delectable to unpalatable. How much of the range is hereditary and how much is nutritional? Breed differences in the taste of poultry meat are slight to undetectable, so I would join most others in supposing that the range in palatability of duck meat is largely nutritional. Thus, the unpopular taste of meat from sea ducks and mergansers reflects what the ducks have been feeding on. At the other end of the range, the canvasback is rated very highly for the taste of its meat, but is instantly disqualified if it has been feeding on rotting salmon.  Probably one of the key features of this dietary effect relates to the digestion of fats and oils in the bird’s diet. Fats and oils are formed from triglyceride - three fatty acids bonded to a glycerol backbone like the three arms of a capital letter E. As the triglyceride is digested and moved around the body to be deposited in the duck’s own fat, nothing happens to the structure of the fatty acids, they just get uncoupled and recoupled to a glycerol backbone. Thus, a fatty acid with an unpleasant taste from rotting salmon can move, unchanged, from the edge of the sea to the edge of your plate (details in LEC 19). 

Two types of ducks have been domesticated and are extensively farmed, these are worth knowing.  The mallard (Anas platyrhynchos) and the Muscovy duck (Cairina moschata). The Muscovy may be identified by its claws (it is able to perch) and a red caruncle or knob between the beak and the eyes. Breast meat from female Muscovies may be tougher, drier and stronger in taste than that from males. The main changes produced by domestication have been to increase growth rates and reduce the colouration of feathers. Carcass conformation is often not much different from a muscular wild duck. Apart from numerous duck breeds of layers and ornamentals, there are many meat breeds around the world. The top ratings might be the Aylesbury in England; the Rouen, Nantes and Barbary in France; and the Long Island in the USA. But this would probably be argued by fanciers of other breeds such as the Blue Swedish, Crested, Pekin, and Black Cayuga. The muscular Muscovy is the winner if meat yield and leanness are the main criteria.

In Canada, ducks are separated into a broiler-fryer category, less than 8 weeks of age, weighing 1.8 to 2.8 kg, either males or females; as distinct from the larger roaster, up to 16 weeks of age, either male or female. In Muscovies, the male is larger than the female. Youthfulness in ducks is detected by softness of the bill, sternal cartilage and trachea.

3.5 Origin of turkeys

History of the word - turkey. Originally, an English turkey-cock was a guinea fowl. Guinea fowl had been introduced from Africa and were a paradigm of showiness, as in Shakespeare’s Twelfth night, “Contemplation makes a rare turkey-cock of him.” With the exploration of North America, the name was applied to the ancestors of the birds we now call turkeys, Meleagris gallopavo.
 The geographical range of wild M. gallopavo is from southern Canada, through the eastern and southern USA, down to Mexico. After the Spanish invasion of Mexico, Mexican strains of M. gallopavo were introduced into Europe where they were gradually improved and assumed the English name of turkey. Thus, when the English and French settled farther north in North America, turkeys (M. gallopavo) were re-introduced as domestic birds which were smaller and more compact than their wild ancestors. Agricultural development then restricted the range of wild turkeys, although they are now successfully conserved in various national parks and protected areas.  In the old days, turkeys were eaten only on special occasions such as Christmas. But turkeys are now eaten every day, partly because of the invention of numerous processed turkey products, ranging from cooked breast meat slices to turkey sausage, and partly because customers have been introduced to a range of relatively small turkey cuts.

Further information

J. Clutton-Brock (1987). A Natural History of Domesticated Mammals. Cambridge University Press, and British Museum (Natural History).  Very scholarly - but easy to read.

L. Alderson. (1994). The Chance to Survive. Pilkington Press,  Yelvertoft, England.  Super pictures and compulsive reading for anyone who loves farm animals.


Bos primigenius.  Water colour of my imaginary butcher's nightmare.
Syncerus caffer. Water colour from the back of a truck in Kruger Park, South Africa.
Duck. Dendrocygna viduata on a farm pond in Brazil (local name Marreca-Piadeira).
Melagris gallopavo, Singhampton, Ontario.