Beef cows kept for the production of feeder calves are usually maintained on pasture and roughages with required amounts of protein supplement and some grain being fed only to first-calf heifers or very heavy milking cows. Most beef cows tend to be overnourished and may become excessively fat and slow to conceive unless they happen to be exceptionally heavy milkers. Most pregnant cows go into the
winter in satisfactory condition and need to gain only enough to offset the weight of the fetus and related membranes. They can therefore utilize coarser roughages, having a total daily crude protein requirement of from 1.3 to 1.7 pounds (0.58 to 0.76 kilogram). Daily vitamin A supplement at the rate of 18,000 to 22,000 International Units per cow is advisable unless the roughages are of a green, leafy kind and the fall pasture has been of excellent quality. Feed requirements for bulls vary with age, condition, and activity, from 2.0 to 2.4 pounds of crude protein per day; from 25,000 to 40,000 International Units of vitamin A; and during breeding periods nearly the same energy intake as calves or short yearlings being finished for market, the main feeding requirement being to prevent their becoming excessively fat. All cattle require salt (sodium chloride) and a palatable source of both calcium and phosphorus, such as limestone and steamed bone meal. Most commercial salts carry trace minerals as relatively cheap insurance against deficiencies that occasionally exist in scattered locations. Beef cattle management
Beef production has become highly scientific and efficient because of the high cost of labour, land, feed, and money. Most brood-cow herds, which require a minimum of housing and equipment, are managed so as to reduce costs through pasture improvement and are typically found in relatively large areas and herds. Other aspects of management include performance testing for regular production of offspring that will gain rapidly and produce acceptable carcasses and the use of preventive medicine, feed additives, pregnancy checks, fertility testing of sires, artificial insemination of some purebred and commercial herds, protection against insects and parasites, both internal and external, adequate but not excessive feed intakes, and a minimum of handling. Calving of beef cows is arranged to occur in the spring months to take advantage of the large supplies of cheap and high-quality pasture forages. Fall calving is less common and occurs generally in regions where winters are moderate and supplies of pasture forage are available throughout the year. Calves are normally weaned at eight to ten months of age because beef cows produce very little milk past that stage and also because they need to be rested before dropping their next calf. Feeder calves sell by the pound, so that weight for age is even more important than conformation or shape. Consequently, crossbred cattle are used; their hybrid vigour results in greater breeding efficiency and milk production on the part of the dam, as well as greater birth weight, vigour, and gaining ability on the part of the offspring. The gestation period is 283 days, and the interval between estrus, or periods in which the dam is in heat, is 21 days. Cows should produce a living calf every 12 months. Pasture breeding, in which nature is allowed to take its course, calls for one mature bull for every 25 cows, whereas hand breeding, in which control is exercised by the breeder, requires half as many bulls. Artificial insemination permits one outstanding sire to produce thousands of calves annually. Diseases of beef and dairy cattle
Dairy cattle are susceptible to the same diseases as beef cattle. Many diseases and pests plague the cattle industries of the world, the more serious ones being prevalent in the humid and less developed countries. One of the more common diseases to be found in the developed countries is brucellosis, which has been controlled quite successfully through vaccination and testing. This disease produces undulant fever in humans through milk from infected cows. Leptospirosis, prevalent in warm-blooded animals and humans, is caused by a spirochete and results in fever, loss of weight, and abortion. Bovine tuberculosis has been largely eliminated; where it has not, it can infect other warm-blooded animals, including humans. Test and slaughter programs have proved effective. Rabies, caused by a specific virus that also can infect most warm-blooded animals, is usually transmitted through the bite of infected animals, either wild or domestic. Foot-and-mouth disease has been eliminated from most of North America, some Central American countries, Australia, and New Zealand. The rest of the world is still plagued by the disease, which attacks all cloven-footed animals. Humans are mildly susceptible to this organism. Successful vaccinations have been developed for blackleg, malignant edema, infectious bovine rhinotracheitis (or red nose), and several other diseases. Anaplasmosis, common to most tropical and semitropical regions, is spread by the bite of mosquitoes and flies. Anthrax, caused by a generally fatal bacterial infection, has been largely eliminated in the United States and western Europe. Rinderpest, once a common affliction, was caused by a specific virus that produced high fever and diarrhea; the disease was declared eradicated in 2011. An infectious fever sometimes called nagana, caused by the tsetse fly, attacks both cattle and horses and is prevalent in central and southern Africa as well as in the Philippines. Grass tetany and milk fever both result from metabolic disturbances. Bloat, caused by rapid gas formation in the rumen, or first compartment of the stomach, is sometimes fatal unless relieved. Pinkeye is an infectious inflammation of the eyes spread by flies or dust and is most serious in cattle having white pigmentation around one or both eyes. Mastitis, an inflammation of the udder, is caused by rough handling or by infection. Vibriosis, a venereal disease that causes abortion; pneumonia, an inflammation of the lungs; and shipping fever all cause serious losses and are difficult to control except through good management. Broad-spectrum antibiotics (antibiotics that are effective against various microorganisms), as well as powerful and specific pharmaceuticals, are effective and profitable means of keeping cattle herds healthy, though their overuse in livestock farming is an important factor in the rise of antibiotic-resistant bacteria. Vermifuges, which destroy or expel parasitic worms, and insecticides, which kill harmful insects, are also highly effective and much used.
