swine

swine, name for any of the cloven-hoofed mammals of the family Suidae, native to the Old World. A swine has a rather long, mobile snout, a heavy, relatively short-legged body, a thick, bristly hide, and a small tail. The name swine is applied mainly to domestic animals, which are also known as hogs. Sometimes these are called pigs, a term which in the United States is more correctly reserved for the young animals. Boar is a term for a male domestic swine suitable for breeding, but the term wild boar is used for the common wild swine, Sus scrofa, of Eurasia and N Africa. There are no true swine native to the New World, although a similar, related animal, the peccary, is found in the deserts and rain forests of parts of N and S America. The wild hogs found in parts of the United States are descendants of the European wild boar, introduced for sport hunting, or hybrid offspring of escaped domestic hogs.

The wild boar may reach a height of 3 ft (90 cm) and a length of 5 ft (150 cm). It has 9-in. (30-cm) tusks and a fierce disposition. Now rare in Europe, it is still common in parts of Asia. The wild boar was domesticated in N Europe c.1500 B.C., and it is believed that modern domesticated hogs are descended chiefly from this European boar, with some admixture of Sus indica, a smaller Asian species domesticated in China c.3000 B.C. Hogs were introduced into the Americas by Columbus on his second voyage in 1493; in 1609 hogs were shipped to the Jamestown colony from England.

Economic Importance

Swine are valuable for their flesh, prepared as ham, bacon, and pork, and for their fat (lard); they also provide many other products, e.g., leather for gloves, footballs, and other articles, and bristles for brushes. Hogs are commonly grouped as meat-type or lard-type, with the former dominating the U.S. farms. Hogs are raised in nearly all parts of the United States, but the corn belt of the Midwest is the chief hog-raising area, with Iowa by far the leading hog-producing state.

A great majority of U.S. hog production has moved from open pens to enclosed, mechanized facilities. The trend is toward huge, factorylike hog farms where swine are born and bred inside structures that feed, water, and dispose of wastes while controlling ambient temperature. Though hogs will eat almost any food, modern swine feed is nutritionally balanced to produce rapid and healthy growth. Based on a mix of corn and soybeans, the feed is supplemented by minerals, vitamins, and antibiotics. The giant modern farms produce enormous amounts of hog waste; this has become of increasing concern as a potential source of water pollution.

Diseases of Swine

Hogs are probably susceptible to a greater number of diseases than any other domestic animal. Respiratory and parasitic ailments are major problems, particularly with limited exercise and lack of sunlight. With an estimated 65% to 85% of U.S. herds exposed to swine pneumonia viruses, drugs are increasingly important to the hog industry. Some swine diseases are transmissible to humans. Among them are brucellosis, trichinosis, and cysticercosis. The last two are supposedly the basis of the first food sanitation codes.

Classification

Swine are classified in the phylum Chordata, subphylum Vertebrata, class Mammalia, order Artiodactyla, family Suidae.

Bibliography

See J. Blakely, The Science of Animal Husbandry (3d ed. 1982); O. Schell, Modern Meat (1984).