Abstract #364

# 364
Understanding the association between hock and knee injuries on lameness in dairy cattle.
A. M. Armstrong*1, T. F. Duffield1, D. B. Haley1, D. F. Kelton1, 1Department of Population Medicine, Guelph, ON, Canada.

Injuries and lameness are both prevalent across the dairy industry, however, there is little research addressing the potential link between them, and whether one predisposes the other. The majority of lameness studies have focused on hoof lesions and attributed lameness to these lesions. Few studies have examined the proportion of lameness that can be attributed to injuries. The objective of this study is to determine the association between mild, moderate and severe hock and knee injuries with lameness in dairy cattle. This research is being conducted at the Livestock Research and Innovation Centre (LRIC), Elora, Canada from November 2017–2018. Working with the hoof trimmer at the LRIC, cows between 120 and 160 DIM, cows entering the lactating herd, and cows that are being examined as a follow-up to a previous lameness intervention, are being trimmed and scored for the presence of hoof lesions. Currently 136 cows have been enrolled in the study: 114 lactating cows, 5 dry cows, and 17 heifers. All cows at the LRIC are also being assessed weekly for lameness to identify and characterize hock and knee injuries. Hock injuries are being scored on a 4-point scale, 0–3; with 0 indicating no swelling and no hair loss; and 3 indicating major swelling (>2.5 cm), a bald area greater than the size of a 25 cent piece and a lesion on the bald area. Of the sampled cows, hock injury scores of 2 or greater were distributed as follows: 44% on right lateral, 15% on right point, 32% on left lateral, and 8% on left point. Lameness is being scored on a 5-point scale, with 1 being sound and 5 being severely lame. Twenty-six percent of cows had a lameness score of 3, 4% a score of 4, and 22% of cows have been treated for lameness. Lesions included digital dermatitis (3%), white line disease (2%), sole ulcers (1%), the remaining 16% were listed as treated with unknown causes. Based on preliminary analysis (Fisher’s exact test), cows with hock injury scores of 2 or 3 were 3.82 (95% CI: 1.55–10.1) times more likely to be lame than cows with a hock injury score of 0 and 1. The projected implications are to provide the industry with information on the association between hock injuries and lameness and what can be done to decrease their prevalence.

Key Words: lameness, hock injury, welfare