Research Progress Report 160
		  December, 1964

Oral Vitamin A, Vitamin E or Vitamin K and Injectable Vitamin A
for Growing Yearling Steers 1,2

T. W. Perry, W. M. Beeson, W. H. Smith and M. T. Mohler Department of Animal Sciences

Summary
Yearling steers which received 20,000 IU of vitamin A per head daily gained 10 percent more rapidly (2.15 vs 1.95 lb per day) than control animals fed no supplemental vitamin A, and 4 percent faster than those injected initially with 4 million units of vitamin A (2.06 lb per day), in 210 day feeding trial.
It should be pointed out that these cattle were started as yearlings and that yearlings tend to have a greater liver storage of vitamin A than is the case for younger cattle. Furthermore, the cattle were receiving 20, 000 IU of vitamin A per head daily before they were put on the experiment.
Plasma vitamin A levels held up very well in the control group through the April 7 bleeding. However, the final analysis taken on May 11 (203 days after the start of the experiment) showed a low value in the
case of the controls, whereas those fed vitamin A or those that had been injected had plasma levels of vitamin A well above the level encountered in typical vitamin A deficiencies.
During the greater part of trial, control animals grew as rapidly as the treated animals, and the blood plasma levels of the controls indicated not a critically low level of vitamin A. The decline in growth rate of the controls paralleled the decline in vitamin A blood plasma levels.
Apparently, the need for supplemental vitamin A during the feedlot period depends on a number of variables such as level of liver storage of the animal at the time it is put into the feedlot; age of the animal; length of the feedlot period; and environmental temperature.
The feeding of 200 mg. of vitamin E per day or 75 mg. of vitamin K per day, or both, was without apparent effect on the

1/ This research was supported in part by a research grant from Hoffmann-La-Roche, Inc., Nutley, New Jersey. Oral vitamins A, E and K and injectable A were furmsie by J. C. Bauernfeind and C . R. Adams, Hoffmann-LaRoche, Inc., Nutley, New Jersey.
2/ The Hereford cattle used in this research were furnished by the Norris Cattle Co., Havana, Illinois^ through the courtesy of G. A. Furgason and Stanley Butt.

PURDUE UNIVERSITY • Agricultural Experiment Station • Lafayette, Indiana