Providing newborn calves with high concentrations of neutralizing antibodies through colostrum is a key management strategy for the reduction of respiratory disease caused by BVDV, BHV-1, BRSV, and PI3 in young calves. When maternally-derived immunity decays, calves become susceptible to acute viral infection and disease. Duration of maternally-derived immunity is dependent on the amount of neutralizing antibodies absorbed from colostrum. Feeding a commercial colostrum replacer is an alternative to provide passive immunity to neonatal calves when availability of maternal colostrum is compromised. The ability of colostrum replacers to provide neonatal calves with an adequate concentration and duration of specific virus-neutralizing antibodies against common respiratory viruses has not been described. The objective of this study was to compare the total serum concentration and duration of BVDV, BHV-1, BRSV and PI3 virus neutralizing antibodies in calves fed maternal colostrum (MC) or a commercial colostrum replacer (CR) at birth.