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

An experiment designed to study some of the physiological 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 experiment, the average increase amounted to 12.4 micrograms per 100ml. plasma in the first 3 days. This increase resulted from an average intake of 99,614 International Units, of vitamin A from colostrum during the first 3 days. When the period of colostrum feeding was extended to 7 days the bloodplasma vitamin A continued to increase, reaching a peak on the seventh day. The levels reached on the 7th day averaged 18.9 micrograms per 100ml. plasma, which was 6.8 micrograms 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 experiment 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. Weight 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.