Lameness accounts for 25% of the culling reasons for sows, but the current evaluation method is mainly through observation. Therefore, the accuracy of detecting lameness varies greatly. The use of force plates has been used to detect lameness in cattle, and this study tries to determine whether force plates can be used for sows as well. The objectives were i)to develop a scale to measure weight distribution per limb ii)to validate the use of force plates for measuring lameness in sows and iii)to determine the effect of analgesics on weight distribution in lame sows.

Results were calculated by measuring the percent of body weight on each limb, measuring the ratio of weight between left and right limbs, and recording the frequency and amplitude of weight shifting between left and right limbs. Weight shifting frequency was found to be significantly different between lame and sound sows in front legs (score 0:22.5 ± 1.64, score 1: 24.77 ± 1.86, score 2: 33.3 ± 1.94, P<0.001), and hind legs (score 0: 20.4 ±1.80, score 1: 21.89 ± 2.04, score 2: 31.3 ± 2.13, P<0.001). The lameness score was measured by observing gait: 0 being normal strides, and 4 being no movement due to lameness. The ratio of body weight distributed between rear legs was also significant with a decreased ratio with increasing lameness score (score 0: 0.72 [0.67-0.76], score 1: 0.71 [0.66-0.75], score 2: 0.62 [0.57-0.68], P<0.05).

Overall, it was found that there was more variation in weight distribution, and increased weight shifting in the lame sows. While force plates seem to be able to detect lameness the precision and thresholds need to be studied further. As well, the force plates cannot detect gait disorders, so it is recommended to still use visual observations.