Newborn calves are often bright, alert and responsive but sensory stimuli like auditory or tactile impulses induced myoclonic jerking of the whole body, including intermittent extensor spasm, hyperaesthesia and nystagmus.
Diagnosis is based on histopathology, where vacuolation of the central nervous system is characteristic of this disease. Either the white or grey matter or both parts of the brain may be affected. Hypomyelinogenesis is also a feature of this disease.
A differential diagnosis would include other congenital myopathies such as muscular dystonia, arthrogryposis multiplex, neuropathic hydrocephalus, progressive degenerative myeloencephalopathy and spinal muscular atrophy.
As this is an hereditary disease, euthanasia is usually required. Most calves do not survive due to the severity of the condition.
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