Rotavirus infections in calves in dairy herds.

Neonatal calf diarrhoea was studied in 115 calves of one dairy herd from January 1976 to June 1977. Two syndromes could be distinguished: a mild and short lasting 'early diarrhoea' within the first three days of life and a usually more severe 'late diarrhoea' from the fourth to the 14th day of life. The latter type of diarrhoea occurred almost exclusively during the first half of the year. Thirty-four out of 45 calves with late diarrhoea excreted rotaviruses, whereas only one of 34 calves with early diarrhoea excreted virus. In addition, rotavirus excretion was found in 11 calves that either remained healthy or had recovered from diarrhoea before virus was first detected. Similar findings were obtained in the spring of 1978 but in addition bovine coronavirus was recovered from four calves with late diarrhoea and from three healthy calves. One faecal sample obtained from a calf with diarrhoea on day 2 yielded K99+ Escherichia coli. Nearly all cows excreted rotavirus-specific antibodies in their colostrum but no relationship was found between the initial colostral antibody titre against rotavirus and the development of rotavirus-associated diarrhoea in the calf.