Ovine neuroaxonal dystrophy in New Zealand

A condition of neuroaxonal dystrophy of Coopworth sheep is described. This was characterised clinically by progressive ataxia from weaning with collapse of hindquarters and ultimately death. One per cent to 10% of the lamb flock on three commerical farms were affected over several years. Histopathological features were bilateral spheroid formation in specific brain stem nuclei and in the dorsal horn (especially in and about Clarke's column) along the length of the spinal cord. The condition appears virtually identical to that recorded earlier in Californian Suffolk sheep and that seen previously in the Romney, Perendale and Coopworth breeds in New Zealand. The cause was undetermined but it is suggested there may be an inherited component, as has been postulated in the Suffolks.