Prevalence and risk factors for skin lesions on legs of dairy cattle housed in freestalls in Norway.

Appropriate indoor housing facilities for dairy cattle promote improved animal welfare. Skin alterations are an indicator of dysfunctional housing. The purpose was to determine the relationship between different housing design and skin lesions, hence providing farmers more insight into how to reduce the occurrence of lesions. A cross-sectional study was conducted on 2,335 animals in 232 Norwegian freestall-housed dairy cattle from September 2006 to June 2007. A model was established to investigate risk factors related to the presence of lesions including hair loss, swelling, and wounds on the legs of dairy cattle. Separate models were developed to investigate risk factors related to the presence of knee and hock lesions. Previously described risk factors were included in the models, together with a questionnaire addressing the attitude of the farmer toward the animals. Mean (+/- SD) prevalence for hock lesions was 60.5 +/- 21.2% with a median value of 64%. The prevalence for knee lesions was 35.3 +/- 25.7% with a median of 30%. Cows in herds with a soft freestall base had an odds ratio (OR) for knee and hock lesions of 0.22 (0.06 to 0.73) and 0.62 (0.48 to 0.80), respectively, compared with those in herds with a harder freestall base, such as concrete and compact rubber mats. There was an increased risk of hock lesions when the length in the lying area in a double-row freestall was >250 cm (OR = 2.96; 1.02 to 8.60) compared with </=250 cm, and when the length of the lying area against a wall was >260 cm (OR = 2.11; 1.53 to 2.90) compared with < or =260 cm. The risk for knee lesions increased if a row against a wall was >270 cm (OR = 1.72; 1.09 to 2.72) compared with < or =270 cm. Hock lesions were associated with lame cows (OR = 5.76; 1.14 to 29.18) versus nonlame cows, and with cows in their second or higher parity (OR = 1.27; 1.06 to 1.52) versus cows in their first parity. Knee lesions were associated with farmers' negative attitudes toward animals in pain (OR = 3.28; 1.79 to 6.03) versus those with positive attitudes; cows in the beginning of their lactation (OR = 1.84; 1.24 to 2.74) versus those at the end of their lactation; and tall animals (OR = 1.27; 1.00 to 1.61) versus shorter animals. These results show that freestall design is important with respect to skin lesions as are the characteristics of individual animals and the farmer.