Cattle

Cattle (*Bos taurus*) are large, domesticated hoofed mammals, part of the Bovinae subfamily and the most widespread species of the genus *Bos*. They are kept as livestock for meat, dairy, and leather, and are also used as draft animals to pull carts and farm tools. In Hinduism, cattle are considered sacred, and killing them is illegal in certain areas of the Indian subcontinent. Some small breeds, like the miniature Zebu, are kept as pets.

The word "cattle" originally referred to movable personal property, especially livestock, and comes from the Anglo-Norman *catel*, related to "chattel" and "capital." "Cow" derives from Old English *cū*, tracing back to the Proto-Indo-European root *gʷṓws*. In older English, "cattle" could mean any livestock, as opposed to wild animals like deer.

Cattle are artiodactyls, walking on two toes (the third and fourth digits). Like all bovids, they can have unbranched horns that are not shed annually. Coat color varies by breed, including black, white, red/brown, and spotted patterns. Bulls are larger than cows of the same breed—for example, British Hereford cows weigh 600–800 kg, while bulls weigh 1,000–1,200 kg. The largest breed, the Chianina, can reach 1.8 m at the shoulder and weigh up to 1,280 kg. Domestic cattle naturally live 25–30 years, but beef cattle are slaughtered at about 18 months, and dairy cows at around five years.

Cattle are ruminants with a specialized digestive system for processing tough plant material like grass. They rely on symbiotic microorganisms—bacteria (e.g., *Fibrobacter succinogenes*), fungi (e.g., *Neocallimastix*), and protozoa (e.g., *Eudiplodinium maggie*)—that produce cellulases to break down cellulose. The stomach has four compartments: the rumen (largest, housing most microbes), the reticulum (smallest, called the "honeycomb"), the omasum (absorbs water and nutrients), and the abomasum (similar to a human stomach). Cattle regurgitate and re-chew their food, swallowing it first into the rumen, then bringing it back to the mouth to grind with molars before swallowing again.

A cow’s gestation lasts about nine months, with a roughly 52:48 male-to-female birth ratio. The udder has two pairs of teats. Artificial insemination is common on farms, allowing selection from many bulls, and estrus can be induced. Copulation is brief, lasting seconds with a single pelvic thrust. Cows seek secluded spots for calving. Semi-wild Highland heifers first give birth at 2–3 years, timing births with food quality. The average calving interval is 391 days, with 5% calf mortality in the first year. Beef calves suckle about five times daily, peaking at 6 am, 11:30 am, and 7 pm, and stay with their mothers until weaning at 8–11 months. Both heifers and bull calves are equally attached to their mothers early on.

Taurine cattle are widespread in Europe, temperate Asia, the Americas, and Australia. Zebus are mainly in India and tropical Asia, the Americas, and Australia. Sanga cattle are primarily in sub-Saharan Africa. These types, sometimes considered separate species or subspecies, include over 1,000 recognized breeds. About 10,500 years ago, taurine cattle were domesticated from wild aurochs in central Anatolia, the Levant, and western Iran. A separate domestication in the Indian subcontinent gave rise to zebu. By 2022, there were over 940 million cattle worldwide. Cattle farming accounts for about 7% of global greenhouse gas emissions. They were among the first domesticated animals to have their genome fully mapped.