Effects of Feeding Aureomycin to Dairy Calves

Abstract

Summary Calves fed hay, concentrate, and milks containing aureomycin hydrochloride in amounts equivalent to 45 mg. daily per 100 lb. body weight, from birth through 60 days of age, made average body weight gains of 50.0 lb., as compared with 45.8 lb. by control animals consuming the unsupplemented ration. Calves, previously fed aureomycin, that were continued from 61 through 120 days on a ration of alfalfa hay plus concentrate containing 50 p.p.m. of aureomycin hydrochloride, made average gains of 76.1 lb., as compared with 66.4 lb. by the control group. The differences in average body weight gains and feed intakes between the supplemented and the unsupplemented groups were not significant. Following removal of aureomycin from the diet of six calves at 61 days of age, the average body weight gain and hay consumption were significantly lower during the ensuing 30 days than for the six animals previously fed the unsupplemented ration. The effects of its removal from the diet at 121 days of age were variable. After aureomycin was removed from the diet, the responses of individual animals varied widely, ranging from cases in which gain rate, feed intake, and appearance were excellent, to some cases in which there were anorexia, reduced growth, excessive lachrymation, and development of diarrhea, rough coat, and thickened, scaly hide. Some animals with mild symptoms recovered within a period of a few days to a few weeks, and some severe cases had not recovered after 50 or 90 days.