Dairy lameness in the South Island

Abstract

A study of 43 South Island dairy farms with a mean herd size of 718 cows used recorded treatments of all lame cases in the 2005-06 season to establish the annual and monthly incidence of lameness and the proportions of different lesions diagnosed as causing lameness. The mean annual incidence of lameness in the participant farms was 26.2%, with a range of 4.3-64.4%. The peak incidence of lameness was in summer months, from approximately 120 days after the start of calving. The respective proportions of lesions diagnosed as causing the treated lame cases were: white line disease, 57.7%; sole bruising, 7.9%; sole ulcer, 3.1%; sole penetration, 8.7%; hoof cracks, 3.7%; interdigital lesions, 9.2%; lesions above the hoof, 3.5%; and undetermined diagnoses, 6.3%. The annual incidence of lameness in this study was greater than previously reported for comparable pasture based systems in the North Island or Australia, and the timing of peak incidence of lameness reported contrasts with other New Zealand and international reports where peak incidence was within 90 days in milk. White line lesions made up a far greater proportion of total lameness lesions in this study compared to other studies of pasture-based systems. The greater annual walking distances that are a feature of large, pasture based herds in the South Island may be an influential factor in the results reported in this study.