A multifocal symmetrical necrotising encephalomyelopathy in Angus calves.

Abstract

To define a neurological disorder in Angus calves. Clinical and pathological examinations were performed on affected Angus calves from a herd experiencing 1% annual mortality from neurological disease. Angus calves developed ataxia, nystagmus, strabismus, muscular tremors, opisthotonus, bruxism, hyperaesthesia, tetanic spasms and episodic convulsions at 2 to 6 weeks of age. Death occurred 4 to 7 days after the onset of clinical signs. GROSS PATHOLOGY: Bilaterally symmetrical, yellow-grey foci were present in the medulla oblongata. Symmetrical degenerative lesions affected the dorsal vagal motor, lateral cuneate and olivary nuclei in the medulla oblongata and sometimes the spinal cord, substantia nigra and cerebellar peduncles. Malacia was characterised by spongiosis of the neuropile, vascular hyperplasia, infiltration of gitter cells, spheroid formation and delayed degeneration of neurones. Angus calves may develop a multifocal symmetrical necrotising encephalomyelopathy.