Purdue University Agricultural Experiment Station Lafayette, Indiana
Mimeo AS-297 November 15, 1961 Final
LEVELS OF SUPPLEMENTAL VITAMIN A WITH AND WITHOUT SUN-CURED ALFALFA MEAL FOR FATTENING STEER CALVES 1/
W. M. Beeson, T. W. Perry, M. T. Mohler and W. H. Smith Department of Animal Science
Summary
Steer calves fed on a ration without alfalfa showed a highly significant increase in daily gain (20%) from an intake of 10, 000 IU of vitamin A per head, daily (Table 1). Steers fed 20, 000 IU of vitamin A per day (Lot 3) gained significantly more than those fed 10, 000 IU per day. Higher levels --30,000, 40, 000 and 50, 000 IU of vitamin A did not improve the performance of the steers over the 20, 000 IU intake. All levels of vitamin A fed resulted in an improvement inefficiency of feed conversion of from 7 to lO.percent.
When sun-cured alfalfa pellets made up 10 percent of the ration, a supplemental level of 10, 000 IU of vitamin A resulted in a highly significant increase in rate of gain, but higher supplemental levels were without effect. An improvement in feed efficiency of from 4 to 7.5 percent resulted from vitamin A supplementation of the alfalfa containing ration. Apparently the cattle were able to convert a portion of their vitamin A requirement from the alfalfa. The rations containing no alfalfa contributed from 15.6 to 18.1 milligrams °f carotene per animal daily, whereas the rations containing 10 percent of alfalfa contributed from 42.0 to 46.5 milligrams of carotene, per animal, daily.
Blood plasma levels of vitamin A were significantly increased by all levels of vitamin A supplementation when compared 10 the controls (Table 3). Fortification with
vitamin A decreased the carotene plasma levels.
Substituting sun-cured alfalfa pellets for 10 percent of corn cobs increased the daily gain 9 percent. When the corn cob ration was fortified with 20, 000 IU of vitamin A (Lot 3) per steer daily, the addition of 10 percent sun-cured alfalfa pellets (Lot 9) did not significantly effect daily gain.
Stilbestrol caused no significant change in daily gain (control, 1.97 lb; diethyl-stil-bestrol, 2. 00 lb) when the ration was not fortified with synthetic vitamin A. However, improvement in daily gain was highly significant when stilbestrol was used in conjunction with vitamin A supplementation. There was no correlation between the different levels of synthetic vitamin A fed and the response to stilbestrol.
Very definite outward symptoms of vitamin A deficiency were observed in cattle fed no supplemental vitamin A. Night blindness was quite apparent when such cattle were driven in the early morning hours. Looseness in the shoulders, enlargement of the brisket and partial paralysis of the hind quarters were observed in the deficient animals.
At the time of sale, cattle from Lots 1 and 7 (no supplemental vitamin A) sold for less than the cattle fed supplemental vitamin A (Table 5). However, the level of vitamin A fed had no consistent effect on either dressing percentage or carcass grade. The inclusion of 10 percent sun-cured alfalfa had a much greater
IT This research was supported in part by a grant-in-aid from Hoffmann-La Roche, Inc., Nutley"10, New Jersey. Vitamin A palmitate (Rovimix A-325) was supplied by the same company.