Feeds for beef cattle vary widely in quality, palatability, and essential nutrient content (see Nutrition: Cattle: Mean Nutrient Content of Feeds Commonly Used in Beef Cattle Diets a). To be most effective, any supplement must be patterned to fit the kind and quality of roughage available. Chemical analyses of roughages are very useful to determine their nutrient deficiencies and adequacies. Under certain systems of management, beef cattle are wintered as economically as possible on low-quality roughages and thus may not receive the recommended nutrients for optimal performance. Low-quality roughages, such as cereal straw, especially if cut and fed to pregnant heifers during the prolonged period of very cold weather in northern climates during winter, may result in outbreaks of highly fatal abomasal impaction. This can be prevented by ensuring that adequate amounts of grain are fed to meet the energy and protein requirements of pregnant heifers during colder weather. This may be acceptable if no serious deficiency signs develop and if the cattle can make up for poor winter gains on abundant, high-quality summer pasture. However, when maximal performance is desired (cows nursing calves, rapid growth of calves, steers and heifers on full feed), nutrient requirements should be met (see Nutrition: Cattle: Nutrient Requirements of Pregnant Replacement Beef Cows a through see Nutrition: Cattle: Nutrient Requirements of Growing Beef Bulls a).
Feeding and nutritional management for 3 systems of beef production are discussed separately. (see Health-Management Interaction: Cattle.)
The Breeding Herd
In many areas, producers follow a spring calving program (February to May in the USA), depending on the available feed, growth of early pasture, and prevailing climate. Fall calving has become more prevalent, particularly in the south. Wintering the lactating cow presents a much greater nutritional problem than does wintering the pregnant, nonlactating cow. Spring-born calves commonly are weaned at 6–8 mo, and their dams bred again while on pasture. Heifers may be bred to calve first as 2-yr-olds (24–27 mo) if good winter feeding is practiced to ensure maximal development and prevent high death loss of dam or calf at parturition. Heifers of British breeds should weigh at least 600–650 lb (275–300 kg) at breeding time (exotic crossbreds should be heavier) and should be fed well thereafter to allow for continued growth, good milk production, and prompt rebreeding.
Mature cows have greater body reserves and lower nutrient requirements than heifers; therefore, they can be wintered on rations of poorer quality. Usually, they are fed hay, fodder, silage, or dry grass free choice. Their ration should provide a minimum of 8% total or crude protein in the dry matter; if it does not, then 1–2 lb (0.5–1 kg) of a 20–30% protein supplement or its equivalent should be fed daily. A mineral mix and salt should be provided.
Mature beef cows may lose >150 lb (67 kg) of body wt from fall until after calving in the spring. Although this weight loss is not desirable, it may not impair reproductive performance in mature cows if spring and summer pastures are adequate. Under most profitable systems of management, a mature beef cow should maintain her weight from fall to fall. Lactation requires more nutrients than gestation. However, feeding beef cows more than is necessary for satisfactory production, such as is frequently done in purebred herds and show herds, is also undesirable. Large accumulations of body fat may lead to lowered conception rates, difficult calving, a lower calf crop, and a shorter life span for the cow.
Often a system of “creep feeding” is practiced in which suckling calves are allowed access to a grain mixture in a self-feeder in an enclosure. A creep-feed mixture might consist of 6 parts shelled corn, 3 parts wheat bran, and 1 part protein supplement (preferably pelleted). The mixture should be rather large particles to prevent dustiness. A commercial 12–14% protein creep feed may be used as an alternative.
Growing bull calves and yearlings should receive ~2 lb (1 kg) of protein supplement, 3–5 lb (1.5–2 kg) of grain, and good-quality roughage. Mature bulls commonly are wintered in the same manner as the cow herd, with a greater feed allowance during the late winter. In highly fitted show bulls, a gradual reduction in the ration and much exercise are needed before they will be in suitable shape and condition for pasture breeding. Breeding stock should have adequate nutrients in their ration and be gaining weight before and during the breeding season. Deficiency of several nutrients, especially carotene, phosphorus, energy, and protein, reduces fertility. These nutrients should be present in adequate amounts in the ration at least 6–8 wk before breeding.
It is common practice to feed calves and yearlings to make moderate gains in winter, with faster and less expensive gains on summer pasture. Such cattle may be sold as feeders in the spring or finished out in dry lot the following fall. The cost of winter gain on harvested feeds invariably is higher than summer gain on pasture; hence, it is advisable to winter cattle so as to make the greatest possible gains on pasture. To maintain good health, weanling calves should gain >1 lb (0.5 kg)/day. Two pounds (1 kg) of grain plus 1–2 lb (0.5–1 kg) of protein supplement are recommended in addition to nonlegume roughage. If legume roughage is fed, no protein supplement is needed. Older cattle, particularly if they enter the winter in fleshy condition, may do well just to maintain their weight. A free-choice mineral mixture and trace mineralized salt should be supplied. Limited amounts of grain fed to yearling cattle on pasture during the late summer may increase their market value.
This phase of beef production consists of full feeding of grain with limited amounts of roughage until market weight and finish are reached. Older cattle may reach finish on pasture alone (or with only a few pounds of grain/day) or after 60–90 days in the feedlot on high-grain rations to improve market grade and to remove any yellow tinges from their body fat (due to stored carotene from pasture forage). Weanling calves commonly are shipped directly to the feedlot and fed finishing rations for 100–150 days; yearlings require ~150 days, and older steers 100–125 days. Grain consumption of cattle on full-feed is ~2–2.5 lb/100 lb (1 kg/45 kg) body wt. Roughage consumption usually is limited to about one-fourth to one-third of the total concentrate consumption after cattle are on full-feed. Cattle consume ~3% of their body wt/day when self-fed mixed rations. For calves, ~1.5–2 lb (<1 kg) of a 33% protein supplement is required daily for best gains and market grades when nonlegume roughage is fed.
The grain (concentrate) allowance for finishing cattle should be increased gradually over 2–3 wk from the time they are started on a finishing program to get them on full feed. Feeding too much grain to finishing cattle too rapidly can lead to lactic acidosis or founder (see Diseases of the Ruminant Forestomach: Subacute Ruminal Acidosis). Self-fed, total mixed rations should contain >50% roughage as cattle are started on feed.
Corn or sorghum silages are very palatable, and cattle of lower grade may be finished principally on silage supplemented with protein and minerals. Alfalfa or grass silage is relatively high in protein, carotene, and minerals but is lacking in available energy. Alfalfa hay is an excellent roughage but may cause bloat in calves if fed as the only feed. Grains for finishing cattle have about the same relative value as indicated by their total digestible nutrient content. Plant-source proteins are equal in value and can be replaced in part by feeding supplements containing urea. For optimal performance, undegraded intake protein, also known as “bypass protein,” should be provided (see Nutrition: Cattle: Protein). Supplements should be fortified with minerals, vitamins, and desired feed additives. A small amount of molasses (1 lb [0.5 kg]/head/day) may improve rations that contain low-quality roughages, such as corn cobs, weathered hays, or cottonseed hulls.
Last full review/revision July 2011 by Thomas H. Herdt, DVM, MS, DACVN, DACVIM; Tilden Wayne Perry, BEd, BS, MS, PhD