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The effect of corrective claw trimming on gait analysis of the sow
Lameness is a major cause of culling in sow herds. The objective of this study was to ascertain kinematic adaptations following corrective claw trimming of sows. In this study, 52 sows individually walked a semi-circular (4 m diameter) then straight chute (0.6 m wide) system pre, 1 h post and 48 h post trimming (PRE, POST1, POST48, respectively). Sows were video recorded simultaneously they passed through the straight chute and moved perpendicularly between two synchronized cameras. The straight chute consisted of 2.4 m each of pre-recording and recording distance, followed by 1.7 m post-recording distance. Sows were electronically timed walking through the recording frame, which each sow repeated until 5 useable repetitions, falling within a 10% deviation of the mean time were achieved. After the pre-trimming videography, claws were correctively trimmed to ~5.5 cm away from coronary band, then videoed at 1 and 48 h post-trimming. Videos were analyzed using a two-dimensional kinematic software program (Kinovea) to assess duration of swing, stance, breakover, stride length, and three-limb support phase. Stride duration and velocity, swing:stance ratio, and both stance and breakover, as percentages of stride duration, were calculated. Data were analyzed using the PROC MIXED procedure of SAS (P < 0.05 significant). Analysis revealed a decrease in overall stride duration (Front: 1.04, 1.02, 0.98; Rear: 1.14, 1.11, 1.07 s for PRE, POST1, respectively; P < 0.0001) and breakover (Front: 0.12, 0.11, 0.10; Rear: 0.14, 0.12, 0.11 s for PRE, POST1, and POST48, respectively; P < 0.0001). Stride length decreased in the front limbs (106.5, 103.7, 104.5 cm for PRE, POST1, and POST48, respectively; P < 0.05) and velocity increased (Front: 104.8, 105.1, 109.7; Rear: 93.2, 95.2, 101.3 cm/s for PRE, POST1, POST48, respectively; P < 0.0001). Three-limb support phase decreased (Front: 47, 46, 42; Rear: 49, 46, 42% for PRE, POST1, and POST48, respectively; P < 0.0001). Breakover as a percent of stride duration decreased (Front: 12, 11, 10; Rear: 12, 11, 10% for PRE, POST1, and POST48, respectively; P < 0.001). This data supports the practice of claw trimming to improve gait efficiency of the sow, which may influence sow longevity and culling rate.
Keywords: claw trimming, lameness, sows