CATTLE

domesticated bovine farm animals that are raised for their meat or milk, for their hides, or for draft purposes. In the terminology used to describe the sex and age of cattle, the male is first a bull calf and if left intact becomes a bull; if castrated he becomes a steer and in about two or three years grows to an ox. The female is first a heifer calf, growing into a heifer and becoming a cow. Depending on the breed, mature bulls weigh 1,0004,000 pounds (4501,800 kg), and cows 8002,400 pounds. Males retained for beef production are usually castrated to make them more docile on the range or in feedlots; with males intended for use as working oxen or bullocks, castration is practiced to make them more tractable at work. All modern domestic cattle are believed to belong to the species Bos taurus (European breeds such as Shorthorn and Jersey) or Bos indicus (zebu breeds such as Brahman) or to be crosses of these two (such as Santa Gertrudis). Many contemporary breeds are of recent origin. The definition of a breed is difficult and inexplicit, although the term is commonly used and, in practice, well understood. It may be used generally to connote animals that have been selectively bred for a long time so as to possess distinctive identity in colour, size, conformation, and function, and these or other distinguishing characteristics are perpetuated in their progeny.