Effect of wet weather on lameness in dairy cattle.

The incidence of lameness in cows recorded by five veterinary practices over one year and one practice over four years was plotted with rainfall and potential soil moisture deficit. Correlation coefficients calculated between lameness, rainfall and potential soil moisture deficit over two-week periods showed the incidence of lameness in summer to be significantly related to the potential soil moisture deficit in the same two-week period and rainfall in the previous two-week period. Differences in patterns of lameness incidence among practices and years were also partly explained by differences in rainfall and potential soil moisture deficit; however, these effects were small compared with those of other factors that affect lameness incidence such as herd size, age and stage of lactation.