Congenital cerebello-cerebral cortical degeneration in a calf.

Among neurodegenerative disorders affecting neurons in the central nervous system of domestic animals is a distinct entity known as multisystem neuronal degeneration which is often associated with significant cerebellar involvement. Occurrence of such a multisystem neuronal degeneration has extremely been uncommon in the bovine species. A female Shorthorn calf clinically presented with progressive ataxic signs that had lasted since birth until her euthanasia at 4.5 months of age. Confirmed histopathologically, the cerebellum exhibited severe and mild cortical degeneration: the former was present in grossly atrophied anterior vermis and flocculonodular lobe, which demonstrated total and subtotal loss of Purkinje and granule cells, respectively; the latter, in grossly normal posterior vermis which displayed varying degrees of Purkinje cell loss, while preserving granule cells. Concurrent with these cerebellar cortical lesions were shrinkage of a few neurons in the olivary nuclei of the medulla oblongata and focal cerebral cortical degeneration comprising neuronal red cell change in the left parietal lobe. This congenital progressive neurodegenerative disorder manifesting as combined cerebellar and cerebral cortical degeneration was regarded as a new variant of multisystem neuronal degeneration in the bovine species, most likely giving rise to a functional impairment of the feedback circuit between the cerebellar and cerebral cortex. This neurodegenerative disorder should be subclassified on clinical and neuropathologic grounds as a descriptive term congenital cerebello-cerebral cortical degeneration.