Cattle, name for the ruminant mammals of the genus Bos, and particularly those of the domesticated species, Bos taurus and B. indica. The term oxen, broadly used, refers also to closely related animals, such as the buffalo and the bison.
Narrowly used, ox refers to a mature castrated male used for draft purposes. In referring to domestic cattle a grown male is a bull, a grown female a cow, an infant a calf, and an animal between one and two years old a yearling. A female that has not given birth is a heifer; a castrated male is a steer.
Most cattle have unbranched horns consisting of a horny layer surrounding a bone extension of the skull; these horns, unlike those of deer, are not shed. Some cattle are naturally hornless. Western, or European, domestic cattle (Bos taurus) are thought to be descended mainly from the aurochs, a large European wild ox domesticated during the Stone Age, extinct since 1627. A smaller species, the Celtic shorthorn, was the most important domestic ox of the Stone Age and may also be involved in the ancestry of B. taurus. The zebu, or Indian ox, B. indica, is the humped domestic species of Asia and Africa. Several B. indica breeds have been developed in the United States into the Brahman breed. The yak, B. grunniens, and other cattle species, wild and domestic, exist in Asia. Domestic cattle were first brought to the Western Hemisphere by Columbus on his second voyage.
In various societies throughout history wealth has been measured in terms of cattle—cattle is related to capital and chattel, and pecuniary is derived from pecus [Lat.,=cattle]. Breeding for improvement of beef and dairy qualities, practiced by the Romans, was established on scientific principles in the middle of the 18th cent. by English livestock breeder Robert Bakewell (see animal husbandry; breeding). Important beef breeds include Angus, Hereford, Simmental, Charolais, Limousin, Gelbvieh, Brahman, and Shorthorn. Important crossbreeds include Brangus (Brahman x Angus) and Santa Gertrudis (Shorthorn x Brahman). Major dairy breeds include Holstein-Friesian, Jersey, Guernsey, Brown Swiss, Ayrshire, and Milking Shorthorn. The importance of dual-purpose breeds has declined.
Cattle are classified in the phylum Chordata, subphylum Vertebrata, class Mammalia, order Artiodactyla, family Bovidae.