The vitamin A requirement for cattle can be met by pro-vitamin A carotene in feeds or vitamin A supplements, or combination of the two.
Vitamin A is needed for normal growth and development including fetal growth, spermatogenesis, and for maintenance of skeletal tissue and epithelia tissue.
Vitamin A also increases disease resistance and has stimulatory effects on cell-mediated immunity.
Cattle store vitamin A and carotene in the liver and in body fat during times of abundant intake from pasture and other feeds. These storage reserves, if sufficiently large, may rely upon for several months of time in reducing or completely covering the needs of cattle for vitamin A.
Growing and finishing steers and heifers fed for several months require about 2200 IU of vitamin A per kg of dry ration; pregnant heifers and cows about 2500 IU and lactating cows and breeding bulls about 3900 IU.
Vitamin A requirement for cattle
