INDIVIDUAL COW RISK-FACTORS FOR CLINICAL LAMENESS IN LACTATING DAIRY-COWS

A case-control study investigating relationships between clinical lame ness and individual-cow (within herd) risk factors was performed in 17 Minnesota and Wisconsin dairy herds. Cases were defined as lactating cows found lame by either of two observers during farm visits in the s ummer of 1989 and spring of 1990 using a uniform scoring system. A sin gle control cow (matched by herd, season, parity, and stage of lactati on) was selected for each case at each visit. Assessments of body weig ht, body condition, dorsal claw angles, and limb lesions were made for each case and control animal. Conditional logistic regression analysi s revealed positive associations between prevalent clinical lameness a nd heavier body weight, lower body condition score, and shallower slop e of rear lateral claw angle. Lesions associated with clinical lamenes s included non-tarsal rear limb superficial swellings, abnormal hoof o vergrowth (including corkscrew claw), and limb lacerations. Superficia l tarsal swellings, intra-synovial tarsal swellings, and carpal swelli ngs were not associated with clinical lameness.