Inactivated scours vaccines for immunization and protection of bovine animals from disease caused by infection with bovine rotavirus and bovine coronavirus, which comprise and effective amount of at least one inactivated viral strain are described. Polyvalent inactivated vaccines further comprising an effective amount of an antigenic component which is protective against one or more additional pathogenic organisms or viruses are also disclosed. Said vaccines are prepared from one or more strains of rota- and coronavirus, C. perfringens Type C bacteria and E. coli bacteria, and combinations thereof. Preferably, a polyvalent inactivated vaccine is provided for parenteral administration. Passive immunity is achieved in neonatal calves via immunization of pregnant cows prior to birth.