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Evaluation of three lameness detection strategies on the odds of cure in dairy cows
The high prevalence of lameness in US freestall dairy herds is both an animal welfare and an economic concern. To achieve a low prevalence of lameness, strategies to lower incidence need to be combined with methods to decrease duration. This requires methods to detect and treat lameness. The objective of this study was to evaluate the impact of three lameness detection strategies on the odds of cure. A trial was conducted from June to August 2015 on a dairy farm in Minnesota. Three pens of cows were randomized to different lameness detection strategies. The strategies were: 1) locomotion scoring using a 3-point scale (VLS), 2) headlock scoring by observing leg posture and weight-bearing while cows were restrained (HS), and 3) casual observation at unspecified times (farm’s current strategy), serving as the control group (C). Cows newly detected as lame by the different strategies were evaluated in a hoof trimming chute and treated for the cause of lameness. All groups were locomotion scored for lameness once per week (LS) as cows exited the parlor. The weekly LS were used as the outcome measure to assess odds of cure. Cows that began non-lame as defined by LS and who were subsequently diagnosed as lame by LS were included in the analysis. The scores from the LS system showed a high degree of week-to-week variability. Logistic regression models were constructed for the odds of cure at 3 wk (n=486) and 6 wk (n=290) following lame diagnosis. At the 3 wk follow-up, 176 individuals (36.2%) remained lame. Primiparous cows had higher odds of recovering than multiparous cows (OR: 1.79 CI: 1.20 – 2.67). Days in milk at enrollment were negatively associated with odds of cure (P = 0.03). There was no significant association between detection strategy and odds of cure at 3 wk. At the 6 wk follow-up, 125 individuals (43.1%) remained lame. Primiparous cows had higher odds of recovering than multiparous cows (OR: 2.71 CI: 1.62 – 4.53). The odds of cure were higher in the VLS group compared to the C group (OR: 2.15 CI: 1.12 – 4.12). The week-to-week variability in individual cow LS identified a limitation of the LS system, as this variation is inconsistent with the pathology of lameness. These results show that the odds of cure improved when the VLS active detection protocol was implemented.
Keywords: Dairy, lameness, locomotion scoring