The prevalence of lameness on New Zealand dairy farms: a comparison of farmer estimate and locomotion scoring.

Lameness is a significant welfare and economic issue in all dairy systems. However, there is only a limited amount of published data on the incidence and prevalence of lameness in the pasture-based systems used in New Zealand. One key area where knowledge is lacking is how well farmer perception of lameness matches that identified by more objective locomotion scoring. Previous studies of this topic have focussed on housed cows. Fifty-nine herds, 26 based in the South Island and 33 in the North Island, were surveyed. All farms were visited on one occasion at the expected peak time for lameness, and data were collected via a questionnaire which included details on farm size, and productivity as well as lameness. The latter included a farmer estimate of the number of lame cows which were currently on-farm and the number of lame cows there had been in the previous 12 months. Whole herd locomotion scoring, using the DairyCo 0-3 scale, was then used to estimate the prevalence of lameness in the herd. Farmers estimated that between 0 and 20% of their herd was lame (mean 2.2%), while locomotion scoring identified that between 1.2% and 36% of a herd was lame (mobility score ≥ 2; mean 8.1%). This finding indicated that, on a herd basis, only 27.3% (range 0-95%) of the cows with reduced mobility had been identified as such. There was no significant effect of herd size or geographical location on this percentage. The prevalence of lameness in this study was much lower than that reported in housed cattle, but the percentage of cows with reduced mobility recognised as lame was very similar. There is significant room for improvement in the detection of lameness on New Zealand farms, where routine mobility scoring, particularly at critical periods, could prove a valuable tool.