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The effect of corrective claw trimming on gait analysis of sows
Problems with feet and legs are a continuous issue and major cause of early culling in sow herds. This is of great concern to producers, as demands for changes to sow housing and flooring are made. The objective of this study was to ascertain kinematic adaptations following corrective claw trimming of sows. In this study, 17 sows individually walked a semi-circular track (4 m diameter) immediately pre-, 1 h post-, and 48 h post-trimming. Pigs exited the track through a circular then straight chute (0.6 m wide) system, where they were video recorded. As sows moved perpendicularly to two synchronized cameras, they were simultaneously filmed on each side. The straight chute consisted of 2.4 m pre-recording distance, followed by 2.4 m recording frame, and 1.7 m post-recording distance. A third camera was positioned to film sows from the rear as they passed through the recording frame. Pigs were timed electronically, as they walked through the recording frame, and repetitions falling outside of a 10% deviation from the mean were eliminated. Each pig was walked until 5 useable repetitions were achieved. After the pre-video, claws were correctively trimmed to between 5 and 5.5 cm in length. Videos were analyzed using a two-dimensional kinematic software program (Kinovea) to assess duration of swing, stance, and breakover, in addition to two- and three-limb support phases. Stride duration, swing:stance ratio, stance as a percent of stride duration, and breakover as a percent of stride duration were also calculated. Data were analyzed using the PROC MIXED procedure of SAS. Analysis revealed a decrease (P < 0.05) in overall stride duration (1.0335, 1.0024, 0.9786 s for pre-, 1 h post-, and 48 h post-trimming, respectively). Decrease stride duration was also indicated by decreased swing time (P < 0.05; 0.4146, 0.4086, 0.3903 s for pre-, 1 h post-, and 48 h post-trimming, respectively) and breakover duration (0.1522, 0.1392, 0.1290 s for pre-, 1 h post-, and 48 h post-trimming, respectively). This data supports the practice of claw trimming to improve gait quality of the sow, which may influence sow longevity and culling rate.
Keywords: Sow, Swine, Gait Analysis, Locomotion