A macrolide antibiotic; active against macrolide-susceptible strains of M. haemolytica, P. multocida, and E. coli (MICs = 4, 4, and 128 µM, respectively), as well as a hyperpermeable strain of E. coli (MIC = 2 µM); inhibits bacterial protein synthesis (IC50 = 0.36 µM); increases serum CK, CK-MB, and MDA levels in mice, indicating cardiotoxicity