BULL

A bull is an intact (i.e., not castrated) adult male of the species Bos taurus (cattle). More muscular and aggressive than the female of the species, the cow, the bull has long been an important symbol in many cultures, and plays a significant role in both beef ranching and dairy farming, and in a variety of other cultural activities.

Bulls are much more muscular than cows, with thicker bones, larger feet, a very muscular neck, and a large, bony head with protective ridges over the eyes. These features assist bulls in fighting for domination over a herd, giving the winner superior access to cows for reproduction. The hair is generally shorter on the body, but on the neck and head there is often a “mane” of curlier, wooly hair. Bulls are usually about the same height as cows or a little taller, but because of the additional muscle and bone mass they often weigh far more. Most of the time, a bull has a hump on his shoulders. When a bull is full-grown, he can weigh as much as 2,000 pounds.

In horned cattle the horns of bulls tend to be thicker and somewhat shorter than those of cows, and in many breeds they curve outwards in a flat arc rather than upwards in a lyre shape. It is not true, as is commonly believed, bulls have horns and cows do not: the presence of horns depends on the breed, or in horned breeds on whether the horns have been disbudded (although in many breeds of sheep it is true that only the males have horns). Cattle that naturally do not have horns are referred to as polled, or muleys.

Castrated male cattle are physically similar to females in build and horn shape, although if allowed to reach maturity they may be considerably taller than either bulls or cows, with heavily muscled shoulders (but not necks).

Bulls become fertile at about seven months of age. Their fertility is closely related to the size of their testicles, and one simple test of fertility is to measure the circumference of the scrotum: a young bull is likely to be fertile once this reaches 28 centimetres (11 in); that of a fully adult bull may be over 40 centimetres (16 in).

Bulls have a fibro-elastic penis. Given the small amount of erectile tissue, there is little enlargement after erection. The penis is quite rigid when non-erect, and becomes even more rigid during erection. Protrusion is not affected much by erection, but more by relaxation of the retractor penis muscle and straightening of the sigmoid flexure. Bulls are occasionally affected by a condition known as “corkscrew penis”. The penis of a mature bull is about 3–4 cm in diameter, and 80–100 cm in length. The bull’s glans penis has a rounded and elongated shape.