Value of Chlortetracycline and Sulfamethazine for Conditioning Feeder Cattle after Transit

Five experiments were conducted to study the effect of daily administration of 350 mg chlortetracycline or 350 mg sulfamethazine alone or in combination or of administering 10 mg diethylstilbestrol, upon the 28-day performance of newly-arrived feeder cattle. In two of the three experiments, in which chlortetracycline alone, its use improved rate of gain. In four of the five experiments a combination of chlortetracycline and sulfamethazine resulted in a significant increase in gain over control cattle administered neither, but the combination was superior to chlortetracycline alone in only one out of three comparisons. The feeding of 10 mg diethylstilbestrol alone or in combination with chlortetracycline and sulfamethazine was without significant effect upon rate of gain.