A comparison of florfenicol-flunixin meglumine versus tulathromycin for the treatment of undifferentiated fever in fall-placed feedlot calves.

The purpose of this study was to compare the efficacy of a new combination drug, florfenicol-flunixin meglumine, with tulathromycin for initial treatment of undifferentiated fever (UF) in fall-placed calves that received metaphylactic tilmicosin on arrival at the feedlot. No significant differences were observed in UF relapses between the two drugs. Calves treated with florfenicol-flunixin had a lower crude case fatality rate (P = .0447) than calves treated with tulathromycin but did not have a significantly lower respiratory disease and histophilosis case fatality rate (P = .12). Whether the new florfenicol-flunixin product is more cost-effective than tulathromycin for the treatment of UF in fall-placed feedlot calves will depend on how the new product is priced in the marketplace relative to tulathromycin.