“Shaker ” Calf Syndrome: A Newly Recognized Inherited Neurodegenerative Disorder of Horned Hereford Calves

Abstract. The clinical and pathological features of a newly recognized, inherited neurodegenerative disorder in homed Hereford calves are described. The disorder is expressed in newborns by tremulous shaking of the head, body and tail, difficulty in rising, a wobbly spastic gait, and aphonia. Transient improvement is followed by deterioration and progressive spastic paraplegia. Generalized tremors can be induced easily by a variety of stimuli, and spinal reflexes may be exaggerated or depressed. The major pathological finding is an excessive accumulation of neurofilaments within neurons of the central, peripheral, and autonomic nervous systems. The involvement of multiple systems of neurons and the similarity with some forms of human motor neuron disease and spinocerebellar degeneration suggest that this unique bovine disease may serve as a suitable animal model for these human neurodegenerative disorders. Several inherited neurodegenerative diseases of cattle have been described in various breeds. Some diseases involve accumulations of storage products, as in man-nosidosis in purebred Angus333 53 GM- 1 gangliosidosis in inbred Friesians,”-19 and neuronal lipodystrophy in Beefma~ters.~ ~ Other diseases are distinguished by wide-spread focal swelling of axons, such as hereditar