Fortunately, the liver of cattle is capable of storing vitamin A for long periods and frequent supplementation is not necessary. A singular injection of one million international units (IU) of vitamin A provides sufficient vitamin for two months to four months in growing and breeding cattle.
"It is important to remember that vitamin A and A,D and E injections have been found – on very rare occasions – to cause a severe reaction to the vaccine," Selk said. "Producers should consult their veterinarian about the use of these products."
Because the daily requirements of beef cows range from 30,000 to 50,000 IU, depending on size, stage of production and level of milk production, supplements can be fortified with vitamin A to supply the minimum daily requirement.
"Depending on the quantity of range supplement being provided, vitamin A can be added to supplements at the rate of 5,000 to 10,000 IU per pound of feed," Selk said.
Anyone interested in obtaining additional information about vitamin and mineral needs for grazing cattle should consult the Oklahoma Cooperative Extension Service circular E-861, "Vitamin and Mineral Nutrition of Grazing Cattle," available through all OSU Cooperative Extension county offices or at http://osufacts.okstate.edu via the Internet.
Cattle and calves are the number one agricultural commodity produced in Oklahoma, accounting for 46 percent of total agricultural cash receipts and adding approximately $2 billion to the state economy, according to National Agricultural Statistics Service data. NASS data indicates Oklahoma is the nation's fifth-largest producer of cattle and calves, with the third-largest number of cattle operations in a state.
Source: Oklahoma State University Extension