Comparative effects of diazinon and malathion in Najdi sheep.

The comparative effects of diazinon and malathion on Najdi sheep were described in sheep allotted as untreated controls, diazinon-treated at 25 mg/kg/d or 50 mg/kg/d, and malathion-treated at 25 mg/kg/d or 50 mg/kg/d. Although serum cholinesterase (ChE) activity was reduced, neither significant clinical signs nor severe pathological changes were produced in sheep dosed orally with 25 or 50 mg diazinon/kg/d for 21 d. Both oral dose levels of malathion were lethal to sheep between 1 and 6 d and caused, prior to death, hyperexcitability, tremors, clonic convulsions, salivation, nasal discharge, incoordination of movement, paresis of the limbs and recumbency. Lesions were widespread congestion and hemorrhage, patchy pulmonary cyanosis, gastroenteritis and hepatonephropathy. These changes were accompanied by increases in the activities of serum SDH and AST, in the concentrations of urea, triglyceride and cholesterol, and decreases in ChE activity and in RBC, PCV and Hb values.