An epidemiological study of winter dysentery in fifteen herds in France.

Winter dysentery is a highly contagious disease of cattle seen most often during the winter months. In the course of an epidemiological study, the management, production, hygiene and previous diseases in 15 herds were characterized by 32 variables. Each herd was then visited twice a week for 8 weeks and 8 to 10 cows were clinically examined during each visit. Winter dysentery occurred in half of the herds during the survey. All data were analysed by classical statistical methods and by multivariate analysis. Mild or severe disease provoked nasal discharge and was associated with significant economic loss. Winter dysentery outbreaks appeared to be associated with small farms in which the area available per cow is either too small or too large, the presence of coronavirus in the faeces and variations in the temperature of the stable and of the drinking water.