Cattle - biology.

Cattle - biology. I INTRODUCTION Cattle, common term for the domesticated herbivorous mammals that constitute the genus Bos, of the family Bovidae, and that are of great importance to humans because of the meat, milk, leather, glue, gelatin, and other items of commerce they yield. Modern cattle are divided into two species: B. taurus, which originated in Europe and includes most modern breeds of dairy and beef cattle, and B. indicus, which originated in India and is characterized by a hump at the withers. The latter are now widespread in Africa and Asia, with lesser numbers imported to North America (primarily in the southern United States), Central America, and northern and central South America. The general characteristics of cattle can be provided through their classification. They belong to the order Artiodactyla (even-toed, hoofed mammals) and the suborder Ruminantia (four-compartmented stomachs and a decreased number of teeth, with the upper incisors missing). Like others of the family Bovidae, they have paired, hollow, unbranched horns that do not shed. Other Bovidae that are so closely related to true cattle that they can still interbreed include the anoa, bison, gaur, Indian and African buffalo, and yak. II DOMESTICATION AND MODERN BREEDS European cattle probably are descended from the wild cattle, B. primigenius, of Europe and were first domesticated in southeastern Europe about 8,500 years ago. The zebu, or Brahman, cattle, B. indicus, were domesticated in southern Asia about the same time or a little later. Early records indicate that cattle were used for draft, milk, sacrifice, and, in some instances, for meat and sport. Some of these early uses have continued in modified forms into the present, such as in bullfighting, as in sacrificing animals for religious purposes, and as in considering cows sacred. The concept and formulation of modern breeds of cattle began in the midregions of England, in northern Europe, and on the Channel Islands during the mid-1800s, and most modern breeds were formed in the latter half of that century. Cattle with similar characteristics, however, were present in these areas even before the concept of breeds became dominant. Today about 274 important recognized breeds exist, and many other varieties and types that could be described have not attained breed status. Thus, new breeds continue to evolve, such as the Brangus, Santa Gertrudis, Charbray, Beef Master, and Braford. III DAIRY CATTLE Dairy cattle are those breeds that have been developed primarily to produce milk. The achievements of careful breeding have been remarkable. For example, in the United States at the beginning of the 21st century, the average dairy cow produced about 6,640 kg (about 14,640 lb) of milk and approximately 242 kg (approximately 534 lb) of butterfat. Individual high-performance cows could produce more than four times this average amount. In North America the major breeds of dairy cattle are the Holstein-Friesian, Ayrshire, Brown Swiss, Guernsey, and Jersey. The ancestors of these animals were imported from Europe, where similar cattle exist today. The Holstein-Friesian came from Holland and adjacent areas, the Ayrshire from Scotland, the Jersey and the Guernsey from the Channel Islands off the coast of England, and the Brown Swiss from Switzerland. Among the major dairy breeds of B. indicus found primarily in India are the Gir, Hariana, Red Sindhi, Sahiwal, and Tharparker. The major breeds show distinctive characteristics that may be used for identification. The Holstein-Friesian is the largest; a mature cow weighs at least 675 kg (1,500 lb). It is followed in size by the Brown Swiss, Ayrshire, and Guernsey. The Jersey is the smallest, with mature cows weighing 450 kg (1,000 lb). Breeds also differ in color. The Holstein is black and white, although some animals may be red and white; the Brown Swiss varies from a very light grayish-brown to dark brown; and the Ayrshire can be red, brown, or mahogany with white. The Guernsey is fawn, with white markings and a yellow skin, and the Jersey may vary from a light gray to a very dark fawn, usually solid in color but sometimes with white spots. Breeds also differ with respect to volume of milk produced and milk composition. Holstein-Friesians produce the largest volume, averaging 7,890 kg (17,400 lb), followed by the Brown Swiss, Ayrshire, Guernsey, and Jersey. Milk from the Jersey contains the highest concentration of fat (5 percent), however, followed by that of the Guernsey, Brown Swiss, Ayrshire, and the Holstein (3.61 percent). See also Dairy Farming. IV BEEF CATTLE Beef cattle have been bred and selected primarily for the production of meat, and many breeds have been developed or adapted for special conditions. The major breeds of registered beef cattle in North America, listed in order of numbers, are Angus, Hereford, Polled Hereford, Charolais, Shorthorn, Santa Gertrudis, Brahman, Brangus, and Red Angus. In recent years, several "exotic" breeds also have been imported, including the Simmental, Gelbvieh, Fleckvieh, Limousin, Maine-Anjou, and Chianina. These later arrivals have been used primarily for crossing with the major American breeds to increase the size and milking ability of the crossbred offspring for commercial production. Herefords are characterized by a red coat color and a white face. Polled Herefords have the same characteristics, but they are hornless (polled). Angus are solid black in color and are polled; the Charolais are white or cream-colored; and the Shorthorn may be red, white, or roan (a mixture of red and white). The Brahman is usually white in color, with large droopy ears, and a large dewlap. The Santa Gertrudis was developed in Texas from crossbreeding the Brahman and Shorthorn breeds, followed by selection and inbreeding to fix characteristics. These cattle were selected and adapted to the arid region where they originated and have been used successfully in other areas with similar climatic conditions. The recent importation and crossbreeding with the "exotic" breeds may result in the establishment of new breeds in North America in the near future. The various breeds of beef cattle also differ in mature size, growth rate, gestation length, and birth weight. Limited data indicate, however, that strains within the breeds may differ as much as the different breeds in many of these characteristics. See also Meatpacking Industry. V DUAL-PURPOSE BREEDS Dual-purpose breeds are breeds that have been selected for both meat and milk production. They include the Milking Shorthorn, Red Dane, Red Polled, and Pinzgauer. Many of the animals classified as either dairy or beef breed, particularly those of continental Europe, could alternatively be classified as dual-purpose breeds. VI DISTRIBUTION Cattle are widely distributed throughout the world. The total world cattle population is estimated to be more than 1.4 billion head, with about 35 percent in Asia, 23 percent in South America, 17 percent in Africa, 12 percent in North and Central America, 10 percent in Europe, and 3 percent in Oceania. The leading countries are, in decreasing order, India, Brazil, China, the United States, Argentina, and Sudan. Beef cattle used for breeding in the United States are estimated at about 34 million head, and the leading states are Texas, Missouri, Oklahoma, South Dakota, Nebraska, Kansas, Montana, Iowa, Colorado, and California. Dairy cattle in the United States are estimated to number 9.2 million head; the leading states are California, Wisconsin, New York, Pennsylvania, Minnesota, Texas, Idaho, New Mexico, Ohio, and Iowa. See also Animal Husbandry; Branding; Diseases of Animals. Contributed By: Perry Thomas Cupps Microsoft ® Encarta ® 2009. © 1993-2008 Microsoft Corporation. All rights reserved.