Presumptive organophosphate-induced delayed neurotoxicity in a paralyzed bull

A case of presumptive organophosphate-induced delayed neurotoxicity in a bull is described. All signs were referable to a focal cervical or diffuse spinal cord lesion. These included recumbency with severe symmetrical paresis of all 4 limbs, the hind limb involvement being greater than the forelimbs. CSF analysis was normal. The bull was killed and necropsied. There were no gross CNS lesions. Histopathologic finds are characterized and their resemblance to lesions observed in delayed neurotoxicity caused by organophosphate compounds is discussed. The bull had been treated with organophosphate insecticide (famphur) 43 days prior to the onset of signs.