Agenesis of corpus callosum in calves.

Agenesis of the corpus callosum is a rare brain defect in cattle, and was described in two calves. It was characterized by the total absence of the corpus callosum, septum pellucidum and hippocampal commissure. Fornices were present but separated. Both calves also had moderate internal hydrocephalus, micrencephaly and a CSF-filled cyst in the longitudinal fissure dorsal to the thalamus. Clinical signs were not specific. Etiology and pathogenesis are unknown. No evidence of inflammation or inheritance was found as cause of the defect.