Effect of rubber flooring on group-housed sows' gait and claw and skin lesions

This study evaluated the influence of floor type on sow welfare in terms of lameness, claw lesions, and skin lesions. In a 2 x 3 factorial design, we have investigated the effect of rubber coverings on concrete floors and the effect of 3 levels of dietary zinc supplementation on locomotion and claw and skin lesions in group-housed sows. Six groups of 21 +/- 4 hybrid sows were monitored during 3 successive reproductive cycles. The sows were group housed from d 28 after insemination (d 0) until 1 wk before expected farrowing date (d 108) in pens with either exposed concrete floors or concrete floors covered with rubber in part of the lying area and the fully slatted area. During each reproductive cycle, locomotion and skin lesions were assessed 4 times (d 28, 50, 108, and 140) and claw lesions were assessed twice (d 50 and 140). Results are given as least squares means +/- SE. Locomotion and claw scores were given in millimeters, on analog scales of 150 and 160 mm, respectively. Here, we report on the effect of floor type, which did not interact with dietary zinc concentration (P > 0.10 for all variables). At move to group (d 28) and mid gestation (d 50), no differences between floor treatments were seen in locomotion (P > 0.10). At the end of gestation (d 108), sows housed on rubber flooring scored 9.9 +/- 4.1 mm better on gait (P < 0.001). Regarding claw disorders, both parameters "heel overgrowth and erosion" (difference of 4.6 +/- 1.8 mm; P = 0.01) and "heel-sole crack" (difference of 3.1 +/- 1.5 mm; P = 0.04) scores were better for sows on rubber flooring at mid gestation (d 50). However, sows on rubber flooring scored worse for "vertical cracks in the wall horn" (difference of 3.4 +/- 1.7 mm; P = 0.04). At the end of lactation (d 140), both "white line" (difference of 2.9 +/- 1 mm; P = 0.02) and "claw length" (difference of 4.7 +/- 1.4 mm; P < 0.001) had better scores on rubber flooring. No differences for skin lesions were observed between floor treatments. The improved scores for gait toward the end of gestation and some types of claw disorders at mid gestation suggest that rubber flooring in group housing has a beneficial effect on the overall leg health of sows. The documented increase in vertical cracks in the wall horn at d 50 requires further investigation.