University of Arkansas, Fayetteville Division of Agriculture


Bovine respiratory disease (BRD) is the most prevalent and devastating disease in U.S. feedlot cattle. This study evaluated the use of isoflupredone acetate in the treatment of BRD. Crossbred male beef calves (n = 192; body weight = 221 ± 3.9 kg) were acquired in two blocks from regional auction markets and transported to the University of Arkansas Stocker and Receiving Cattle Unit. Calves were observed daily for signs of respiratory illness. Antibiotic treatment was administered if calves displayed signs of respiratory illness and rectal temperature was ≥40 °C. Calves (n = 72) requiring antibiotic treatment were assigned randomly to either treatment 1 (florfenicol) or treatment 2 (florfenicol plus isoflupredone acetate). Treatment efficacy was determined by rechecking the rectal temperature of treated cattle 48 hours post treatment. Blood was collected (at treatment and recheck) via jugular venipuncture to evaluate complete blood count. Weights were recorded on days 0, 14, 28, 45, and 46. No difference existed for medical cost (P = 0.54) or temperature at recheck (P = 0.43). Upon recheck, neutrophils were higher and lymphocytes were lower in calves that received isoflupredone acetate (P ≤ 0.04). No difference existed in overall white blood cell count at recheck (P = 0.67). Calves that received isoflupredone acetate tended to exhibit greater (P = 0.09) average daily gain (ADG) between days 14 and 28 of the study. Results indicate that using isoflupredone acetate as ancillary therapy in the treatment of BRD did not have a positive effect on overall ADG or medical costs.