Some Physiological Effects of Extending the Colostrum Feeding Period of Dairy Calves

Abstract

An expt. designed to study some of the physiol. effects of extending the colostrum feeding period was carried out on 36 dairy calves. In substantiation of the reports of others it was found that calves are born with low reserves of vitamin A but with ascorbic acid reserves considerably above that of later life, as measured by the level of these constituents in the blood plasma. Blood plasma vitamin A increases rapidly following the ingestion of colostrum. In the calves receiving no other supplement, in this expt., the av. increase amounted to 12.4 [gamma] per 100 ml. plasma in the first 3 days. This increase resulted from an average intake of 99,614 Units of vitamin A from colostrum during the first 3 days. When the period of colostrum feeding was extended to 7 days the blood-plasma vitamin A continued to increase, reaching a peak on the 7th day. The levels reached on the 7th day averaged 18.9 [gamma] per 100 ml. plasma, which was 6.8 y above that of 7-day-old calves which had received colostrum for 3 days. Calves which received colostrum for 7 days had blood-plasma vitamin A values which averaged almost identically the same at 21 days of age as that of those which received colostrum for 3 days plus a 10,000 I. U. vitamin A capsule daily for the first 21 days. None of the variations in feeding procedure employed in this expt. appreciably influenced the level of ascorbic acid in the blood plasma. None of the calves receiving colostrum for 7 days showed any signs of digestive disturbance during the period of colostrum feeding. Wt. records indicate more rapid gains in calves receiving additional colostrum. The economy of using the colostrum not nursed by the calf for calf feeding purposes is pointed out.