Risk factors of lameness in sows in England.

Lameness in pigs is a major welfare concern and one of the most commonly reported reasons for premature culling of breeding sows. In this study, the prevalence of lameness in sows was estimated using data from 76 pig breeding units in England and risk factors associated with the occurrence of lameness were examined. The prevalence of lameness in sows was 4.5% (farm median 5.0%, range 0-40%), with at least one lame sow being observed at 54% of the 76 farms. Relative risk (RR) of lameness was determined by multivariable Poisson regression analysis. Farms with high producing sows had a lower rate of lame sows than farms with a medium level of production (P=0.01). However, medium levels of production on a farm were associated with higher levels of lameness than farms having the lowest level of production (P=0.02). Farms where the stockman had responsibility for more sows resulted in an increased risk of lameness (P=0.0062). When indoor units were considered, the area of the pen and younger sows (two parities or less) had higher risk of lameness (P=0.001 and P=0.026 respectively). An increased awareness of the risk factors behind lameness is essential in farm management and can be useful when designing housing areas as well as developing future prevention plans for lameness.