Digestion Coefficients and Nitrogen Retention of Young Dairy Calves as Affected by Antibiotics and Advancing Age

Abstract

Eleven Holstein bull calves were used to study the effect of the antibiotics, chlortetracycline and bacitracin, and of advancing age on the digestibility of feed and the nitrogen retention of dairy calves. Four calves were used as controls, four received chlortetracycline and three received bacitracin. Both antibiotics were fed orally at the rate of 40 mg. per 100 lb. body weight per day from 3 days of age throughout the experiment. Fecal and urinary collections were made when the calves were 7 and 16 weeks old. There was no effect on the digestibility of dry matter, ether extract, crude fiber or nitrogen-free extract. Chlortetracycline increased both the apparent protein digestibility and nitrogen retention (P<0.05). At 16 weeks as compared with 7 weeks apparent protein digestibility (P<0.10) and nitrogen retention (P<0.05) were also increased. Copyright © . .