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The effect of overgrown claws on behavior and claw lesions of sows in farrowing crates
This study evaluated the relationship between overgrown rear claws and other types of claw lesions (CL), and their effect on behavior of sows in farrowing crates. The study used 24 multiparous sows (mean parity 4.7), 13 with overgrown (OG) rear claws (68±12.6mm) and 11 controls (48±5.2mm). All front and hind weight bearing claws were examined for CL on the day of transfer to the farrowing crate (d110 of gestation) once the sows were lying down. CL were scored according to severity using a 4-point scale. A total lesion score for the front and hind feet and overall total lesion score were calculated. Behavioral measurements focused on the period prior to farrowing and 1wk later. Twenty sows (13 control and 9 OG sows) were video recorded for approximately 12 h before farrowing to capture postural behavior for 6 h prior to the birth of the first piglet. An index of the proportion of time spent in different postures was calculated by sampling sow postural behavior every 10 min. Lying-down behavior and sow behavior while standing at feeding were directly observed during 3 feeding events within a week of farrowing, commencing approximately 10 min prior to feed delivery and terminating once the sows resumed lying. For the behaviors while standing, the average number of bouts/min was calculated. Data were analyzed using the Kruskal Wallis test in PROC NPAR1WAY of SAS. There was no difference (P > 0.05) between treatments in the lesion scores of the front claws on d110. Sows on the OG treatment had higher scores in the hind claws for cracks in the wall (P < 0.05), cork screw dew claws (P < 0.05) and higher total hind feet lesion score (P < 0.05) on d110. There was no difference between treatments in the time sows spent in the different postures prior to farrowing (P >0.05). One week after farrowing sows on the OG treatment spent less time standing (P < 0.05) and feeding (P < 0.01) and slipped (P < 0.05) and shifted their weight (P < 0.05) between the hind feet more frequently than control sows. Sows on the OG treatment also made more attempts to stand up (P < 0.01) and had a shorter latency to lie-down (P < 0.01) after feeding. Overgrowth of the hind claws was associated with increased scores for other types of claw lesions, with an increase in slipping and weight shifting and disruptions to feeding and lying/standing behavior in the farrowing crate.
Keywords: Lactating sows, lying-down behavior, overgrown claws, postural behavior