Cow (Bos taurus): Cattle Facts, Breeds, Diet and Lifespan

What is a cow?

In everyday English, “cow” is used for any domestic cattle, but strictly it means an adult female that has given birth. The male is a bull, a castrated male is a steer or bullock, and a young female is a heifer. The full set of terms, including ox and calf, is explained in What is the difference between a cow and a bull?.

Cattle belong to the family Bovidae, the same family as the American bison, the African buffalo, goats, sheep and antelopes. Within the genus Bos, close relatives include the yak, the gaur and the banteng, and cattle can interbreed with several of them.

Scientists still debate how to classify the two main types of cattle. Humpless taurine cattle of Europe, western Asia and temperate regions are Bos taurus taurus, and humped zebu cattle of South Asia and the tropics are either a subspecies, Bos taurus indicus, or a separate species, Bos indicus. A third, mixed type called sanga is common in sub-Saharan Africa.

Domestication: from aurochs to cattle

All cattle descend from the aurochs (Bos primigenius), a huge wild ox that once ranged from western Europe and North Africa to India and East Asia. Aurochs bulls stood up to about 1.8 m (5 ft 11 in) at the shoulder and carried forward-curving horns up to 80 cm (31 in) long. The last known aurochs, a cow, died in Jaktorów Forest in Poland in 1627.

Archaeology and genetics show that taurine cattle were domesticated roughly 10,500 years ago in the Near East, in an area covering central Anatolia, the northern Levant and western Iran. Mitochondrial DNA suggests the founding herd may have been surprisingly small, possibly only about 80 animals. Zebu cattle came from a separate domestication of the Indian aurochs in what is now Pakistan. Since then, people have moved cattle almost everywhere, mixing the two lines in many regions.

Over the centuries, farmers shaped cattle into more than 1,000 recognized breeds. Some are bred mainly for milk, some for beef, some for draft work and some for all three.

Appearance and well-known breeds

Cattle are heavy, barrel-bodied animals with a broad head, a wet muzzle, a long tail ending in a tuft called the switch, and cloven hooves: each foot rests on two toes, the third and fourth digits. Coats can be black, white, red, brown, gray or cream, either solid or patched. Both sexes can grow horns, which are permanent and never shed, but naturally hornless (polled) breeds exist and many farm animals are dehorned when young.

Zebu cattle have a fatty hump over the shoulders, a loose fold of skin (dewlap) under the neck and often drooping ears. These features help them cope with heat, and zebu breeds also tend to resist ticks better than taurine cattle.

Some familiar breeds:

• Holstein-Friesian: the black-and-white dairy cow, the most common dairy breed in Europe and North America and the highest milk producer.
• Jersey: a small, fawn dairy breed from the Channel Islands, known for rich, creamy milk.
• Aberdeen Angus: a naturally hornless Scottish beef breed, black or red.
• Hereford: an English beef breed, red with a white face.
• Highland: a shaggy, long-horned Scottish breed that thrives in cold, wet hills.
• Chianina: a white Italian breed and the tallest and heaviest cattle in the world.
• Brahman: an American beef breed built from zebu cattle, common in hot regions.

How big is a cow?

Size depends heavily on breed and sex. The smallest breed, India’s zebu-type Vechur, averages about 87 cm (34 in) at the shoulder and around 130 kg (290 lb). At the other end, mature Chianina bulls can stand 1.8 m (5 ft 11 in) tall and often exceed 1,600 kg (3,500 lb).

Bulls are usually about the same height as cows of their breed but much heavier, with thicker bones and a massive, muscular neck. More detail, including the heaviest cattle on record, is in How much does a cow weigh?.

What do cows eat?

Cattle are herbivores that graze mainly on grasses and clover, wrapping their long, rough tongue around plants and tearing them off. Like other ruminants, they have no upper front teeth; instead they press plants against a hard dental pad on the upper jaw. Given a choice, grazing cattle have been found to prefer a mix of roughly 70% clover and 30% grass. On farms they also eat hay, silage and grain.

The key to their diet is the stomach, a single organ divided into four compartments: the rumen, reticulum, omasum and abomasum. Microbes in the huge rumen break down cellulose, the tough material in plant cell walls that the cow cannot digest by itself. Cattle swallow food quickly, then later bring it back up as cud to chew again, spending many hours a day ruminating. The whole process is explained in How many stomachs does a cow have?.

Fermentation in the rumen produces methane, which cattle release mostly by belching. A single cow can give off around 100 kg (220 lb) of methane a year, which is why cattle farming accounts for a noticeable share of global greenhouse gas emissions.

Senses and intelligence

Vision is the main sense of cattle. Their eyes sit on the sides of the head, giving a panoramic field of view of about 330 degrees, but only a narrow band of 30–50 degrees where both eyes overlap for judging depth. Like most mammals, cattle are dichromats: they see blues and yellows but cannot tell red from green, which is why a bullfighter’s red cape is not what makes a bull charge (see Do bulls hate red?).

Smell matters in social life: cattle can tell when other cattle are stressed from chemical signals in their urine. Studies show that cattle remember the locations of food for weeks, recognize individual herd mates and people, and that calves prefer their own mother’s calls to those of other cows.

Herd behavior and social life

Cattle are strongly social herd animals and become stressed when kept alone. Within a herd they form a dominance hierarchy, with older and larger animals usually at the top. Most disputes are settled by threats, head-pushing and displacement rather than real fights, which keeps injuries rare. Herd mates also lick and groom each other, usually lower-ranking animals grooming higher-ranking ones.

A cow sleeps only about 4 hours a day in total, and she lies down to sleep deeply. Cattle spend much of the rest of the day grazing and lying down to chew the cud.

Reproduction and calves

Heifers usually first calve at about 2 years old on farms, often a little later in hardy hill breeds. Pregnancy lasts about nine months, close to 283 days on average, and a cow normally has one calf. Slightly more bull calves than heifer calves are born, at a ratio of roughly 52 to 48. A heifer born as the twin of a bull calf is usually infertile, a condition called a freemartin.

Before giving birth, a cow often seeks a quiet, secluded spot. A newborn calf typically weighs 25–45 kg (55–100 lb), depending on breed, and can stand within an hour or so. Under natural conditions, calves suckle several times a day and stay with their mothers until weaning at about 8–11 months. On dairy farms, calves are usually separated from their mothers soon after birth so the milk can be collected, a practice that welfare groups criticize.

Young bulls become fertile at around 7 months of age, but most male cattle on farms are castrated. Many dairy farms now use artificial insemination instead of keeping a bull.

Lifespan

Cattle can live about 15–20 years under good conditions, and some live past 25; animals in sanctuaries often reach their late teens or twenties. The famous Irish cow Big Bertha died in 1993 aged 48 years and 9 months, which Guinness World Records listed as the oldest cow ever recorded. Farm cattle live much shorter lives: beef animals usually go to slaughter at around 18 months, and dairy cows at about five years. The details are in How long do cows live?.

Cows and people

Cattle have shaped human history. The English word “cattle” comes from the same root as “capital” and “chattel,” because herds once meant wealth, and cattle are still used as currency and bride wealth in parts of Africa. Oxen pulled plows across Europe and Asia for thousands of years and still work in many countries today.

In Hinduism the cow is sacred, and killing cattle is illegal in several Indian states and in Nepal. The bull appears as the sign of Taurus in the Western zodiac and the ox is one of the twelve animals of the Chinese zodiac.

Today about a quarter of the world’s meat comes from cattle, and cow’s milk is the basis of butter, cheese and yogurt. An average Holstein cow in the United States produces about 10,000 kg (22,000 lb) of milk a year. Cattle also raise environmental questions: grazing and feed crops use large areas of land, and the methane from rumen fermentation contributes to climate change.

Myths and facts

• “Cows sleep standing up.” False. Cattle can doze on their feet, but they lie down for deep sleep.
• “Only bulls have horns.” False. Horns depend on breed, not sex; in horned breeds, cows have horns too.
• “Red makes bulls angry.” False. Cattle cannot tell red from green; bulls react to movement.
• “Cows have four stomachs.” Not quite. They have one stomach with four compartments.