Claw horn lesions in mid-lactation primiparous dairy cows under pasture-based systems: Association with behavioral and metabolic changes around calving.

The objectives of this study were to describe the lying behavior of primiparous dairy cows under pasture-based systems during the pre- and postcalving period and characterize the association of lying behavior and analytes related to energy metabolism during this period with claw horn disruption lesion development later in lactation. Our convenience sample included 39 primiparous Holstein cows from 3 commercial farms that were assessed for body condition score (BCS; 5-point scale, 0.25-point increments) and had blood collected at wk -3, -2, -1, 1, 2, and 3 relative to calving date. Blood samples were assayed for nonesterified fatty acids, β-hydroxybutyrate (BHB), and cholesterol concentrations. Electronic data loggers (HOBO Pendant G Acceleration, Onset Computer Corporation, Bourne, MA) recorded lying behavior at 1-min intervals from 3 wk before calving to 3 wk after calving. Starting at 4 wk after calving and until 16 wk after calving, cows were examined for claw lesions at approximately 4-wk intervals. Sole lesions and white line lesions were scored on a 0 to 10 scale. Of the 39 primiparous cows, 19 cows scored 0 at all exams during the entire study period and 20 cows had at least 1 severe lesion (score ≥4) between 8 and 16 wk after calving. Time spent lying before calving averaged 10.3 ± 0.3 h/d, but declined to 7.3 ± 0.3 h/d after calving (least squares means ± standard error). At calving, we noted an increase in the number of lying bouts (12.9 ± 0.45 bouts/d) compared with the pre- and postcalving averages of 11.6 (±0.53) and 9.1 (±0.47) bouts, respectively. Cows that developed claw lesions later in mid lactation spent less time lying down than cows without lesions during wk 3 after calving compared with healthy cows (7.29 ± 0.22 vs. 8.51 ± 0.16 h/d). Lesion cows had fewer lying bouts per day, and these bouts were of longer duration than no-lesion cows after calving. Increased odds of lesion were found to be associated with shorter lying times and fewer number of lying bouts during wk 3 (odds ratio = 1.23). Nonesterified fatty acids (747 ± 58 vs. 990 ± 86.85 µmol/L) and BHB (0.77 ± 0.06 vs. 0.60 ± 0.04 mmol/L) concentrations during wk 1 were greater in cows that developed claw lesions relative to cows that did not develop lesions. The BHB concentrations also remained higher in wk 2 for cows that developed claw lesions (0.63 ± 0.04 vs. 0.46 ± 0.03 mmol/L) compared with cows that did not develop any lesions. Cows that developed lesions experienced greater losses in BCS from wk -3 to 3 than cows without lesions (0.74 ± 0.01 and 0.61 ± 0.01 BCS change, respectively). In summary, changes in lying behavior and energy metabolic status after calving were associated with claw horn disruption lesions in mid-lactation primiparous cows under pasture-based systems.