Bos taurus
aurochs
(Also: domesticated cattle)

Like most domestic animals, Bos taurus (domestic cow) is currently found throughout much of the world. The wild ancestors of cows were native to northern Africa, Europe, and southern Asia. (Nowak, 1997)

Domestic cows are common and can be found throughout the world. Cattle are born and raised on rangelands. Rangelands are unfertilized, uncultured, and not irrigated. Also, they must contain adequate areas for grazing.

Domestic cows are large, sturdy animals. Weight ranges from 147 kilograms to 1363 kilograms, and height from 49-52 inches. The body is covered in short hair, the color of which varies from black through white, reddish brown, and brown. Domestic cows have short necks with dewlaps hanging below the chin. They have two hollow horns and a long tufted tail. They can be used as working animals for plowing and moving heavy loads. Domestic cows have no upper incisors, instead they have a thick layer called the dental pad. The jaws are designed for the circular grinding motion used to crush coarse vegetation. (Rath 1998; Walker et al. 1975 Reprogen 1997) (Rath, 1998; Reprogen, 1997; Walker et al., 1975)

Maximum lifespan in domestic cows may exceed 20 years. However, lifespan is often limited by human culling. (Nowak, 1997)

Cow herds are structured according to a dominance hierarchy. Each individual must yield to those above it in the hierarchy. Calves adopt their mother's status in the hierarchy. Females are often protective of their young and chase anything that threatens them. Females also share parental care within the group. Dominant males maintain this status until defeated by younger males in challenges. (Hindsaw 1993; Walker et al. 1975) (Hinshaw, 1993; Walker et al., 1975)

Cows communicate via chemical signals, touch, visual cues, and sounds. They perceive their environment primarily using the same set of senses.

Domestic cows feed on grasses, stems, and other herbaceous plant material. An average cow can consume about 70kg of grass in an 8 hour day. Cows twist grasses around the tongue and cut them with their lower teeth. Domestic cows are ruminants. Ruminants have a special system of digestion which allows for the breakdown of the relatively indigestible plant material which they consume. Cows have a four chambered stomach including a rumen, reticulum, omasum, and abomasum. Grass passes through the rumen where it is mixed with specialized bacteria. From the rumen it moves to the reticulum, where it is broken down further. The partly digested food, known as cud, is regurgitated and chewed. It is then swallowed and moves into the omasum and abomasum, where digestive enzymes break it down further and nutrients are absorbed. The process of digestion takes 70-100 hours, one of the slowest passage rates of all animals. This method of digestion permits ruminants to obtain the most nutrients possible from these plant materials.

(Rath 1998; Hindsaw 1993; Walker et al. 1975) (Hinshaw, 1993; Rath, 1998; Walker et al., 1975)

The wild ancestors of domestic cows were likely preyed on by large carnivores such as wolves, lions, humans, and bears. The majority of predation would have been on calves or sick and elderly individuals. Currently cows are sometimes preyed on by large, wild carnivores but the vast majority of predation is by humans. Their large size and herding behavior would have provided protection against predators.

Cows modify environments through grazing. In areas where their population numbers are artificially increased by humans, they can severely impact natural systems, causing erosion, introduction of non-native grasses and herbaceous plants, destruction of riparian habitats, and overgrazing.

A negative aspect of domestic cattle husbandry is the transmissible spongiform encephalopathy, Bovine Spongiform Encephalopathy, better known as Mad Cow Disease. An outbreak in British cattle has caused international concern and resulted in multiple human infections. Mad Cow Disease is a fatal degenerative brain disease, which is caused by a protein known as a prion. In humans, the equivalent of bovine spongiform encephalopaty is Creutzfeldt-Jakob Disease ("CJD"), which causes a rapid dementia, and neurological damage leading to death. The disease is now believed to be linked to eating beef from infected cows. This disease has killed many people in Europe, therefore causing a ban on all importation of British beef by European countries.

In addition, range cattle are responsible for the transmission of diseases to native wildlife and rapid, and sometimes irreversible, damage to natural ecosystems.

(Brown 1996) (Brown, March 1996)

Domestic cows are used widely by humans for a variety of purposes. Cows are used primarily for dairy products (milk, cheese, etc.) and meat. They are also used for things such as medicines, glue, soap, and leather. Males are used for pulling large loads or for plowing the soil because of their large size and strength. The dung is a good source of fertilizer and fuel. Cows are also often important culturally and as a form of currency. (Rath 1993; Hindsaw 1998; Encyclopedia Britannica Online 2000) ("Britannica.com", 1999-2000; Hinshaw, 1993; Nowak, 1997; Rath, 1998)

There is some interest in conserving rapidly disappearing rare breeds and breeds that may have desirable qualities, such as Texas longhorn cattle and a number of older European breeds. However, as a species, cattle are not threatened.

A Holstein's spots are like a fingerprint or snowflake. No two cows have exactly the same pattern of spots. (Schmitt 1995) (Schmitt, August 1995)

Zebu cattle, which originated in India, are sometimes known as a separate species, Bos indicus. However, current taxonomy recognizes zebu cattle as only a type of Bos taurus. Zebu cattle are characterized by a hump over the shoulder, drooping ears, and large dewlaps. They are well-adapted to arid, tropical climates and are especially resistant to the effects of heat, parasitic insects, and ticks. (Nowak, 1997)