Comparison of treatment protocols for bovine respiratory disease in high-risk, newly received beef calves

This research evaluated the effects of different antibiotic treatment protocols on performance, morbidity, antibiotic usage, and cost in high-risk, newly received beef calves. Crossbred male calves (n = 176; BW = 232 ± 1.6 kg) were stratified by BW and castration status and assigned randomly to 1 of 2 treatments in a randomized complete block design. Calves were administered either 2.5 mg/kg of BW of tulathromycin (TUL, Draxxin, Zoetis, Florham Park, NJ) with a 7-d post-metaphylactic treatment or 10 mg/kg of BW of tilmicosin (TIL, Micotil, Elanco Animal Health, Greenfield, IN) with a 1-d post-metaphylactic treatment. Clinical attitude scores [0 (normal) to 4 (moribund)] were assigned daily to assess morbidity and when ≥ 1, and if rectal temperature exceeded 40°C, an antibiotic was administered per preplanned protocol. Calves that received TUL on d 0 received ceftiofur with a 7-d post-treatment interval, and those that received TIL received enrofloxacin with a 3-d post-treatment interval. A final antibiotic was administered to calves that were pulled a second time and met the treatment criteria. Percentage morbidity was greater for the first treatment, the second treatment, and relapse in TIL compared with TUL (P < 0.0001). Initial antibiotic cost was greater in calves administered TUL compared with TIL (P < 0.0001). Both first- and second-treatment antibiotic costs were greater in TIL compared with TUL (P ≤ 0.0003). However, there were no differences across treatments in overall antibiotic cost (P = 0.51), exclusive of labor or chute charges. Metaphylactic treatment protocols did not affect growth performance, but differences were found in the percentage of calves treated for clinical bovine respiratory disease and in number of antibiotics used.