Clinical and microbiological field studies in The Netherlands of diarrhoea in pigs at weaning.

A longitudinal study investigated the clinical signs and aspects of the aetiology of diarrhoea in pigs at weaning. Two litters of pigs were randomly selected from each of four Dutch herds with a history of diarrhoea after weaning. The pigs were inspected and faecal samples were collected daily. Before weaning, enterotoxigenic Escherichia coli was isolated from only two pigs but after weaning from all the pigs. Before and after weaning, rotaviruses were detected in almost all the pigs during one to four episodes. Rotavirus or enterotoxigenic E coli were generally detected when the pigs had diarrhoea; however, they were also encountered in normal faeces. In many faecal samples from pigs with diarrhoea no pathogenic agent was detected. In almost all the pigs after weaning, E coli types appeared and predominated transiently before they were superseded by another type. This study confirms the results of others in showing that rotaviruses and E coli are important in the aetiology of diarrhoea in pigs at weaning. However, diarrhoea after weaning is probably not caused by these two agents alone; other factors also probably contribute to the syndrome.