Comparison of tilmicosin to gamithromycin for on arrival treatment of bovine respiratory disease in feeder steers

A trial was conducted in a commercial feedlot in western Canada using fall-placed feedlot calves at moderate risk of bovine respiratory disease (BRD) to compare the efficacy of gamithromycin to tilmicosin for metaphylactic treatment of BRD. First-pull treatment rates for BRD were significantly lower (P=0.01) in calves in the gamithromycin group than in the tilmicosin group. There were no other significant differences in health or performance between the two groups. The 6.6 percentage point difference in treatment rates for BRD equated to a net advantage of $0.03 CAN/head for those calves given gamithromycin as a metaphylactic drug on arrival compared to metaphylactic treatment with tilmicosin. Drug cost and disease risk should be carefully evaluated in each feedlot and group of incoming cattle to determine the most cost-effective metaphylaxis protocol.