Neuraxial oedema of Hereford calves with and without hypomyelinogenesis.

The clinical and pathological features of 11 Hereford calves with neuraxial oedema with and without hypomyelinogenesis are described. Calves were affected at birth, recumbent and showed intermittent extensor spasm and hyperaesthesia. Nystagmus was noted in six cases. Pathologically, vacuolation of the central nervous system was seen in all cases. In two calves of horned Hereford stock this was restricted to white matter areas, while in the remaining calves of polled Hereford origin it was distributed in both white and grey matter. Hypomyelinogenesis was also a feature of this latter group of calves.