Safety trial of a bovine respiratory syncytial virus vaccine in feedlot calves

During 1985, 4 separate groups of steer calves (total number = 422) were observed for 28 days after arrival at a feedlot. 213 calves had been vaccinated with 2 ml of modified-live bovine respiratory syncytial virus vaccine before arrival. A booster vaccination was given 2 weeks later. 209 calves were unvaccinated. No adverse local or systemic reactions were seen in the vaccinated calves. No statistical differences were seen in morbidity and mortality rates, average sick days and average daily weight gain between the vaccinated and control calves.