Vitamins for Beef Cattle and Sheep
L. L. Wilson, J. B. Outhouse, H. H. Mayo, and K. G. MacDonald, Animal Sciences Department
Vitamins are organic chemical compounds which are nutritionally essential, but are required in very small amounts. Vitamins occur naturally in plant and animal products. However, there is a wide variation in the amount of each vitamin contained in different feeds. Vitamin activity of forages and grains may be reduced by weathering, handling, heating, or harvesting at advanced stages of maturity.
Vitamins A, D, E, and K are called (t "fat-soluble" vitamins because they are soluble and carried in fats. The B-complex and vitamin C are "water-soluble" and are soluble in water but not fats.
Different vitamins show deficiencies in different ways. Visual deficiency symptoms associated with different vitamins are not frequently found under farm situations. In practical feeding situations a lack of certain vitamins can result in reduced weight gains and feed efficiency, lowered resistance to disease, and lowered fertility in breeding stock before visual deficiency symptoms appear.
This publication presents some of the current facts on vitamin deficiencies, requirements, and supplementation for beef cattle and sheep. Although vitamins A, D, and E receive first consideration in beef cattle and sheep, all vitamins will be discussed.
Vitamin A
One of the chief functions of vitamin A is to maintain health of the soft, moist tissues; such as the mucous membranes of the respiratory system. Consequently, vitamin A helps prevent many respiratory illnesses such as pneumonia.
Deficiencies - Loss of appetite, rough haircoat, lowered weight gain and reduced feed efficiency are the deficiency symptoms that appear first and are most important in farm situations. More advanced symptoms are night blindness (inability to see well in poor light), swelling of legs and brisket, poor muscular coordination, watery eyes, infertility, abortions and weak or dead calves or lambs. A common deficiency symptom in breeding herds and flocks is lowered fertility and calving or lambing percent.
Vitamin A storage - Relatively large amounts of vitamin A can be stored in the liver and other tissues of beef cattle and sheep when they receive a surplus in their rations. The length of time required for an animal to suffer deficiency symptoms depends on the quantity stored in the, body. Since younger animals have a greater requirement in proportion to their weight, calves and lambs may show deficiencies in one to two months if a ration does not contain the required amount for the animal. Yearlings and mature animals
Beef Section • Animal Sciences Department Cooperative Extension Service, PURDUE UNIVERSITY, Lafayette, Indiana
Beef  Nutrition