Longevity of breeding sows in relation to leg weakness symptoms at six months of age

The objective of this study was to evaluate the influence of leg weakness s ymptoms measured early in life (at 6 months of age) on the longevity of the sows, i.e. the age at culling due to locomotory problems in a Danish pig h erd. One hundred and eighty-seven gilts at 6 months of age were selected ac cording to different let: weakness symptoms and were followed until culling and judged for leg weakness once in every gestation using a scale from I ( normal) to 4 (severe changes). Age at culling, and the main and secondary r easons for culling were recorded. The influence of leg weakness symptoms on longevity was evaluated by survival analysis. Though only 12% of the gilts showed a stiff locomotion half of the sows had suffered from this and near ly one third had been distinctly lame at some time in their life, Buck-knee d forelegs, upright pasterns, legs turned out, standing under position and swaying hindquarters were associated with stiff locomotion or lameness, whe reas weak pasterns on hind legs and splayed digits on forelegs were associa ted with brisk movement (freedom from locomotor problems). The following le g weakness symptoms at the gilt stage were found to have significant negati ve effects on longevity: buck-kneed forelegs, swaying hindquarters, and sta nding under position on hind legs.