Abstract #455

# 455
Association between hoof lesions and milk yield in dairy cows.
B. O. Omontese*1, R. Bellet-Elias1, A. M. Argüello1, G. D. Catandi1, R. Casagrande1, Z. Rodriguez1, R. S. Bisinotto2, G. Cramer1, 1Department of Veterinary Population Medicine, University of Minnesota, St. Paul, MN, 2Department of Large Animal Clinical Sciences, University of Florida, Gainesville, FL.

The objective of this study was to evaluate the association between specific hoof lesion (HL) and milk yield in dairy cows. Jerseys were enrolled at 20 ± 3 DIM (d20), evaluated for HL and body condition (BCS). At 120 ± 3 DIM (d120), cows were reexamined for HL and BCS. At the end of lactation, test day milk yield data for each cow was retrieved. According to HL category at d20, cows were grouped as healthy (n = 1,171), hemorrhage (n = 278), noninfectious (n = 103), and infectious HL (n = 34). To assess the relationship of HL development with milk yield, cows were grouped as healthy (no HL at d20 and d120; n = 308), cured (with HL at d20 and no HL at d120; n = 72), new (no HL at d20 but with HL at d120; n = 587), and chronic (with HL at d20 and d120; n = 208). Separate repeated measures linear mixed models were built using test day milk yield as outcome. Variables of interest offered to the model included the fixed effects of HL status, test day number (1–10+), interaction between HL status and test number, parity (1, 2, >3), BCS and calving season. A total of 1,584 cows comprising 13,655 test day milk yield records were used in the final analyses. Of all the HL diagnosed at d20, hemorrhage (69% of HL) was the most common, followed by other noninfectious HL (24%) and infectious HL (7%). Overall, the average test day milk yield was 20.8 kg (95% CI: 20.2 to 21.4 kg). Cows with HL at d20 had reduced milk yield beginning from the 3rd test day with the greatest losses of up to 1.78 kg (95% Confidence Interval (CI); −2.7 to −0.9 kg) by the eighth test day. Cows with noninfectious HL at d20 had reduced milk yield with the greatest losses of up to 4.7 kg at the eighth test day compared with healthy herdmates (95% Confidence Interval (CI); −6.3 to −3.1 kg). Cows that developed new HL produced more milk from the second to fifth test days compared with healthy cows with the greatest milk yield of 1.8 kg (95% CI: 0.9 to 2.8 kg) at the fourth test day of lactation. We conclude that having a lesion in early lactation has a negative impact on productivity and that higher milk production was risk factor for HL development.

Key Words: lameness, milk yield, Jersey