Abstract #W7

# W7
Epidemiology of lameness during the dry period.
R. R. Daros*1, H. K. Eriksson1, D. M. Weary1, M. A. G. von Keyserlingk1, 1Animal Welfare Program, Faculty of Land and Food systems, University of British Columbia, Vancouver, BC, Canada.

Lameness during the dry period of dairy cows has received little attention in dairy research. The aim of this study was to describe: 1) lameness incidence and cure rates during the dry period, and 2) the risk factors for the onset and cure of lameness during this period. We followed 455 dairy cows on 6 freestall dairy farms in British Columbia, Canada. Cows were gait scored (1 to 5) weekly for 8 wk before calving. Body condition score (<3.0 = thin, 3.0 to 3.5 = good, > 3.5 = fat) was assessed 1 wk after enrolment. Parity was retrieved from farm records. Onset of lameness and lameness cure rate were assessed based on changes in gait scores over the study period. Cows were considered lame when gait score was ≥4, or when scored 3 on 2 consecutive assessments. Likewise, cows were considered sound when gait was ≤2 for 2 consecutive scorings. Approximately 45% of cows were hoof-trimmed before enrolment (mean ± SD = 20 ± 12 d before). Two multilevel logistic regression models using farm as random effect were fitted to assess risk factors for: 1) lameness onset (becoming lame vs remaining sound) and, 2) lameness cure (curing lameness vs remaining lame). Lameness Incidence rate was 8.2 cases/wk and cure rate was 7.1 cases/wk; cumulatively these cases resulted in 50% of cows becoming lame and 36% of cows curing from lameness during the dry period. We noted an interaction between parity and hoof-trimming; multiparous cows had higher odds (OR: 4.7; 95% CI: 1.4 – 17.2; P = 0.02) of becoming lame if they were trimmed, while primiparous cows showed the opposite pattern (OR: 0.2; 95% CI: 0.1 – 0.7; P = 0.02). Multiparous cows had lower odds (OR: 0.3; 95% CI: 0.1 – 0.9; P = 0.04) of being cured compared with primiparous cows, and thin cows had lower odds (OR: 0.2; 95% CI: 0.1 – 0.9; P = 0.04) of being cured compared with cows in good body condition. In conclusion, the lameness incidence was high during the dry period. Hoof-trimming in the weeks before dry-off was associated with reduced odds of becoming lame during the dry period for primiparous cows but not for multiparous cows.

Key Words: hoof-trimming, cure rate, incidence rate