Tulathromycin A (CP 472295) is a macrolide antibiotic.

Antibacterial:1 microg/ml (MIC90 for Pasteurella multocida)

145 calves were inoculated by two highly pathogenic strains of M. bovis (with minimum inhibitory concentration values for tulathromycin of 1 and >64 μg/ml). Four days after inoculation, calves with clinical BRD were treated subcutaneously with saline or tulathromycin (2.5 mg/kg). Compared with saline, BRD-related withdrawals, peak rectal temperatures, and lung lesion scores were significantly lower for tulathromycin-treated calves (P < .01). Tulathromycin was highly effective in the treatment of BRD due to M. bovis in calves regardless of the minimum inhibitory concentration of the challenge strain (1 or >64 μg/ml). The MIC90 for tulathromycin were 1 μg/ml for Pasteurella multocida (bovine), 2 μg/ml for Mannheimia (Pasteurella) haemolytica, and 2 μg/ml for Pasteurella multocida (porcine) and ranged from 4-16 μg/ml for Actinobacillus pleuropneumoniae and from 0.5-4 μg/ml for Histophilus somni (Haemophilus somnus).

Each study randomly allocated 250 calves to receive tulathromycin at 2.5 mg/kg and 250 calves to receive either florfenicol at 40 mg/kg or tilmicosin at 10 mg/kg on arrival at the feedlot. Calves were housed by treatment group in pens with 50 calves/pen. The treatment groups were physiologic saline (n=160) given SC at 0.02 ml/kg, tulathromycin (n=20) given SC at 2.5 mg/kg, and tilmicosin (n = 320) given SC at 10 mg/kg.