Mass medication in reducing shipping fever-bovine respiratory disease complex in highly stressed calves.

One thousand and eighty-five newly received, stressed calves were used in studies to determine the effectiveness of certain mass medication procedures for reducing morbidity from shipping fever-bovine respiratory disease complex. In two experiments, im injections of oxytetracycline at 11 mg/kg body wt for 3 successive days reduced treatment days/calf purchased 21 (P less then .05) and 31% (P less than .05). Oral administration of 150 mg of sulfadimethoxine/kg body wt reduced treatment days/calf purchased 20 (P less than .05) and 54% (P less than .05) in the same two experiments. When sulfadimethoxine followed oxytetracycline on the third injection day an 81% reduction in treatment days/calf purchased was obtained, indicating an additive effect of the two drugs. The use of long acting oxytetracycline and sustained release sulfadimethoxine at the time of processing resulted in a 90% reduction in treatment days/calf purchased (P less than .01) and required only one handling of the calves for mass medication purposes.