Mild to severe scouring could be produced in colostrum-deprived calves with tissue culture adapted rota virus and faecal material from field cases of calf diarrhoea. The faeces of experimentally infected calves contained rotavirus for at least 3 days. Pathogenic bacteria were present in one calf only and this calf also showed the most severe gastroenteritis. Eight calves were vaccinated with a live rota viral calf diarrhoea vaccine and subsequently challenged with infective rota virus. Mild scouring was observed after vaccination, but the calves remained normal after challenge. Rotavirus particles were detectable in the faeces for a few days after vaccination and challenge.