AS-364 April 1967
Summary
Fattening cattle fed a ration of ground yellow corn, soybean meal and minerals may develop a vitamin A deficiency. Symptoms of this deficiency are depressed rate of gain, lowered resistance to heat stress, edema, stiffness, depressed appetite and inability to see in subdued light.
A supplemental level of 20, 000 I.U. of vitamin A per head daily in winter and ^	30,000 I.U. per head daily in summer is the
f recommended level of feeding for typical cattle. Under stress conditions higher supplemental levels may be justified.

Research has indicated that cattle grazing good pasture obtained no measurable benefits from supplemental vitamin A except for higher liver stores.
Cattle fed both vitamin A and alfalfa meal gained more rapidly than those fed either one alone, but, neither vitamin A nor alfalfa completely replaced the effect of the other.
Orally administered vitamin A and injected vitamin A produced similar effects. Levels of either 4 million I.U. or of 6 million I.U. injected initially gave more nearly optimal reserves after 210 days in the feedlot than did a level of 1 million I.U. injected initially.
W. Perry, W. M. Beeson, W. H. Smith and M. T. Mohler, Department of Animal Sciences
Levels of Supplemental Vitamin A
Research was conducted to determine the optimum level of supplemental vitamin A for fattening beef cattle confined to drylot in summer and winter. The complete mixed rations were 8 parts ground ear corn to 1 part soybean meal, fortified with 0.7 percent steamed bonemeal and 0.3 percent salt with cobalt (1 ounce cobalt carbonate per 100 pounds salt). Free choice minerals of 2 parts bonemeal to 1 part loose salt, plus loose salt in another compartment of the mineral box were available. The analysis of the ration was: 11.6 percent crude protein; 0.21 percent calcium; 0.34 percent phosphorus; and 1.0 milligram carotene per pound.
Results showed that the optimum level of supplemental vitamin A appeared to be near 30,000 I.U. per day for summer feeding, and near 20, 000 I.U. per day for winter feeding.
Certain of the vitamin A deficiency symptoms were more severe during the hot summer months. Animals on the control diets fed no supplemental vitamin A appeared to be quite uncomfortable during the hot weather as indicated by varying degrees of panting. In
addition, difference in feed consumption between the control and vitamin A-supplemented
lots was greatest during the hot weather. Deficient cattle gave indication of night blindness as evidenced by running into objects in the early morning hours.
Beef Section • Animal Sciences Department Cooperative Extension Service, PURDUE UNIVERSITY, Lafayette, Indiana
The Role of Vitamin A in the Nutrition of Fattening Beef Cattle
Beef  Nutrition