Housing of pregnant sows in loose and confined systems--a field study. 2. Claw lesions: morphology, prevalence, location and relation to age.

A field study of 36 Norwegian sow herds was conducted over a 12 month period, 18 herds had loose housing of pregnant sows and 18 herds had confined (stalled or tethered) dry sows. Fifteen of the loose housing herds had partly slatted concrete floors while 3 herds had other kinds of flooring. The types of claw lesions that were observed in these herds are described. The most prevalent lesions on both loose sows and confined sows were side wall cracks, heel lesions, cracks in the white line and overgrown heels. The lateral hind claws were the most frequent location for lesions and they were more severe than at other sites. These lesions tended to show a bilateral occurrence. More than 96% of slaughtered loose sows and 80% of slaughtered confined sows had at least 1 lesion on the lateral hind claws. The prevalence of claw lesions showed no obvious age pattern. However the prevalence seemed to be lower for the first litter sows and increased slightly thereafter, especially in the confined herds.