EFFECT OF VITAMINS A AND E, CAROTENE AND DEHYDRATED ALFALFA PELLETS ON THE PERFORMANCE OF BEEF STEERS
Research Progress Report 13 April 1962
W. M. Beeson, T. W. Perry, W. H. Smith, M. T. Mohler and Lois Reitz Department of Animal Sciences 1/
Summary
Supplementing the ration with either 12, 500 or 25, 000 I. U. of vitamin A per steer daily caused a 5. 7 and 8.7 percent increase in daily gain and 4.7 and 7.1 percent improvement in feed efficiency, respectively (Table 1). Response to vitamin A fortification has not been as marked as usual because to date the steers have not been depleted of their original vitamin A stores (see blood data in Table 3). No clinical symptoms of vitamin A deficiency have been noted.
Fortification of the diet with 50, 000
I.U. of beta-carotene resulted in essentially the same improvement in gain and feed efficiency as 12, 500 I. U. of vitamin A.
These data support the present conversion factor (National Research Council Bulletin on Beef, No. 579) that beta-carotene has 25 percent the activity of vitamin A or the ratio is 4 to 1.
Vitamin E fed at the rate of 40 I. U. per steer daily had no effect on gain or feed conversion when fed singly (Lots 5 & 11) or in combination with 12, 500 I. U. of vitamin A (Lots 6 & 12).
Feeding 0.5 pound of dehydrated alfalfa pellets resulted in no significant effect on
gain or feed efficiency of steer calves, and there was no interaction between alfalfa pellets, vitamin A, beta-carotene and vitamin E.
Blood plasma levels of vitamin A were significantly (P<0.01) increased by supplementing with either 12, 500 or 25, 000 I. U. of vitamin A. Vitamin E caused no significant change in vitamin A or carotene blood levels. Feeding 0.5 pound of dehydrated alfalfa pellets resulted in a significant (P<0.01) increase in carotene values, but "DeHy" alfalfa pellets had no effect on vitamin A blood levels. No clinical symptoms of vitamin A have been detected.
Based on 3 years research at Purdue, recommendations for fortification of cattle rations with biologically active vitamin A are as follows:
1.	Growing and fattening rations--20, 000 I. U. vitamin A per steer or heifer daily.
2.	Growing and fattening during summer months (hot weather)--30, 000 I.U. of vitamin A per steer or heifer daily.
3.	Breeding stock--30, 000 I. U. of vitamin A per animal daily.
1/ This research was supported in part by a research grant from Hoffmann-La Roche Inc., Nutley, N.J. Carotene, vitamin A and vitamin E were furnished through the courtesy of J. C. Bauernfeind and C. R. Adams, Hoffmann-La Roche Inc., Nutley, N.J.
PURDUE UNIVERSITY • Agricultural Experiment Station • Lafayette, Indiana