Rapid Communication: Use of pressure mat gait analysis in measuring pain following normal parturition in dairy cows.

Research investigating the pain of normal parturition is lacking as there are few objective methods for measuring pain. The objective of this research was to describe the gait of cows following eutocia using pressure mat gait analysis; and if meloxicam alters the gait of cows. Twenty Holstein cows within 26 h of unassisted calving were enrolled into the study. Treatment groups included: 1) postpartum cows administered meloxicam (MEL; n = 10); and 2) postpartum cows administered placebo (PLBO; n = 10). Meloxicam was administered by oral bolus at 1 mg/kg within 26 h of calving. Placebo cows were given an oral bolus of dry whey powder within 26 h of calving. A commercially available floor mat-based pressure/force measurement system was used to compare ambulation between treatment groups. Cows were walked across the mat before treatment administration, and 2, 4, 6, 8, 12, 24, 48, and 72 h posttreatment. The percent of total force, percent total contact pressure, and percent total impulse of the rear limbs were calculated. Outcome measures were statistically analyzed using repeated measures, with the cow serving as the experimental unit. Cows in the MEL group placed 48.9% (95% CI: 47.4% to 50.5%) of total force on the rear limbs compared to 46.3% (95% CI: 44.7% to 47.9%) in PLBO cows (P = 0.02). Total impulse on their rear limbs for the MEL cows was 50.5% (95% CI: 48.6% to 52.4%) compared to 46.7% (95% CI: 44.8% to 48.7%) for the PLBO cows (P = 0.01). No differences in contact pressure of the rear limbs were observed (P = 0.27). The PLBO cows had a longer gait 101.3 cm (95% CI: 95.9% to 106.6 cm) vs. 90.8 cm (95% CI: 85.4% to 96.1 cm) (P = 0.03). These findings show meloxicam-treated cows have altered weight distribution to the rear limbs as measured by pressure mat gait analysis, suggesting meloxicam may effectively treat postpartum pain.