Comparison of tulathromycin, tilmicosin, and gamithromycin for metaphylactic treatment of high-risk calves for control of bovine respiratory disease

Abstract

Cross-bred heifer calves (n = 579; initial bodyweight 404 ± 27.4 lb; 183.3 ± 12.4 kg) were utilized in a randomized, complete block design to compare 3 different antibiotics for control of bovine respiratory disease (BRD) in light-weight feeder heifers. Cattle originated from southeast Texas and were shipped approximately 700miles(1125 km) to the Clayton (New Mexico) Livestock Research Center. Heifers were randomly allocated off the truck into 30 pens, and administered 1 of 3 metaphylactic treatments at initial processing: 1) tulathromycin (TUL; 1.13 mg/lb (2.5 mg/kg)); 2) tilmicosin (TIL; 6 mg/lb (13.3 mg/kg)); or 3) gamithromycin (GAM; 2.72 mg/lb (6.0 mg/kg)). Heifers administered TUL had 0.29 lb (0.13 kg) greater (95% Cl = 2.27 to 2.46) average daily gain than cattle administered GAM. Cattle administered TUL had a lower (5.2%; 95% Cl = 1.2 to 9.1) morbidity rate than calves in the TIL (14.6%; 95% Cl = 6.7 to 22.5) and GAM (12.79%; 95% Cl = 7.7 to 17.9) groups. There were no differences in DM I or mortality in cattle between treatments.