Subclinical laminitis in dairy cows: use of severity of hoof lesions to rank and evaluate herds.

Thirteen high-yielding Holstein herds in Ohio were ranked according to the prevalence and severity of lesions associated with subclinical laminitis (pododermatitis aseptica diffusa). One hundred and seventy-three first lactation cows, most of them in their first 100 days of lactation, and 30 pregnant heifers were assessed. The lesions evaluated were yellow waxy discoloration of the sole, haemorrhage of the sole, separation of the white line, and erosion of the heel. Each herd consisted of more than 100 lactating cows and all the herds were producing over 8500 kg of milk per cow on a rolling herd average basis. The lactating cows were housed in cubicles and maintained in concrete yards. The lesions associated with subclinical laminitis were prevalent among the 13 herds, but when each category of lesion was considered independently, significant differences in prevalence and severity were detected among the herds. These differences suggest that it may be possible to make changes in herd management which may influence the prevalence of lesions.