Antibiotics in Dairy Cattle Nutrition. V. Comparative Effects of Streptomycin and Aureomycin on the Growth and Well-Being of Young Dairy Calves

Abstract

Summary This experiment was initiated to compare the effects of streptomycin with aureomycin on the growth and well-being of young dairy calves. Thirty-six calves were divided into four groups with nine calves each. Calves in one group received 30 mg. aureomycin daily for each 100 lb. of calf weight, a second group received 30 mg. of streptomycin, a third group received 90 mg. of streptomycin, and a fourth received no antibiotic and served as a control. All calves were started on the experiment at birth and continued until 16 weeks of age. Both levels of streptomyem appeared to produce a slight growth stimulation, especially during the first few weeks of life, but this stimulation was not statistically significant nor so great as the stimulation obtained with aureomycin. The calves receiving aureomycin grew at a significantly faster rate than the control calves. Both streptomycin and aureomycin appeared to reduce the incidence of calf infection; however, aureomycin appeared to be slightly the more effective of the two. Also, both streptomycin and aureomycin-fed calves required less TDN and digestible protein per pound of gain than the control calves. The aureomycin-fed calves made more efficient gains than those fed streptomycin. In general, there was no difference between the two levels of streptomycin in regard to rate of weight gain, incidence of disease, or feed efficiency.