Association between lameness risk assessment and lameness and foot lesion prevalence on dairy farms in Alberta, Canada.

Lameness is a detrimental health and welfare concern of dairy cattle with high prevalence in North American herds. As a practical and farm-specific approach toward its mitigation in Alberta, Canada, a score-based lameness risk assessment questionnaire (RAQ) was developed for veterinarians to conduct with their clients; however, its accuracy in identifying risk for lameness and hoof lesions has not been evaluated. Our objectives were to (1) provide an update on prevalence of lameness and hoof lesions in Alberta freestall herds, (2) validate the RAQ by determining the association between RAQ scores and the prevalence of herd lameness and herd lesions, and (3) determine the association between presence of common hoof lesions and lameness. For the first 2 objectives, 65 Alberta dairy farms were visited between March and October 2018 to collect a completed RAQ, hoof trimming records from their hoof trimmer, and video footage of the entire lactating herd. For the third objective, 10 participant herds were visited twice between November 2013 and June 2014 to take video footage of the entire lactating herd and collect hoof trimming records from their hoof trimmer within 48 h after video footage collection. Median herd-level lameness prevalence was 20% (range = 2-56%), infectious lesion prevalence was 10% (range = 0-49%), and noninfectious lesion prevalence was 15% (range = 2-39%). Of cows that were lame, 93% had a lesion, whereas 21% of cows with a lesion were lame. Cows with an infectious and noninfectious lesion were, respectively, 1.5 and 3.1 times more likely to be lame than cows with no lesion. Total RAQ score and herd lameness prevalence were correlated (r = 0.26) and noninfectious RAQ score and noninfectious lesion prevalence were correlated (r = 0.45), whereas infectious RAQ score and infectious lesion prevalence were not. Cow-level mixed logistic regression models indicated no associations between any of the RAQ scores and presence of lameness or a hoof lesion. Lameness prevalence in Alberta remains high, indicative of a low adoption rate of mitigation strategies by producers. Improvement of the RAQ could allow for better reflection of lameness and lesions on farm and can be achieved through further risk factor analysis within the RAQ, which may result in removal or addition of questions as well as the adjustment of scores based on risk factors' strength of association with lameness and lesions.