Spinal muscular atrophy in Braunvieh calves]

Clinical, neurophysiological and histopathological findings of sixteen cases of spinal muscular atrophy in calves are described. The first clinical signs usually were noticed at 2-6 weeks of age. The animals showed weakness in the hindquarters, trembling and ultimate recumbency. There was a marked muscular atrophy in all four extremities. In addition, secondary bronchopneumonia was evident in 11 cases. Histopathological lesions consisted of degenerative changes in the neurons of the ventral horns and the axons of the spinal cord as well as degeneration of nerve axons in the extremities. Neurophysiological measurements revealed spontaneous activity in the muscles of the limbs. The conditions is autosomal recessive. So far 11 bulls have been identified and excluded from breeding.