Winter outbreaks of laminitis in dairy calves: aetiology and laboratory, radiological and pathological findings.

During the winter months of 1984 to 1989, outbreaks of laminitis occurred in up to 6 per cent of all the dairy calves aged four to six months on a dairy farm in a village in Israel. The clinical signs were reluctance to move, an arched back, overgrown hooves, supracoronary swelling and occasional walking on the carpus; most of the calves were unthrifty. Owing to the regular recurrence of the disease, the feeding and haematological, radiological and pathological changes in both the affected and normal calves at the farm, and in normal calves at another farm in the same village were studied. In the affected calves there were significant increases in serum protein concentration and in the activities of creatine phosphotinase and gamma-glutamyltransferase. Radiography showed dilated PIII vascular channels and some PIII rotation. Post mortem studies revealed haemorrhages in the laminar section of the hoof. The management of the farms differed in the protein level of the milk replacer and the 'starter' diet used during the first few months. The affected farm used feeds containing 18 per cent digestible protein whereas the unaffected farm used feeds containing 15.3 per cent digestible protein.