Toxicity of ethion in goats

Cholinesterase activities were measured in plasma and in red blood cells from 6 goats after iv injection of the organophosphorus insecticide ethion at 3 different dose levels--2 mg/kg, 5 mg/kg and 10 mg/kg. Plasma levels of ethion after injection were established. At 2 mg/kg no signs of toxicity were observed and the blood cholinesterase activity remained above 65% of the control value. After administration of the higher doses the goats showed signs of severe toxicity corresponding to increased parasympathetic stimulation. Cholinesterase activities in blood were reduced to approximately 10% of the control value for the 5 mg/kg group and to approximately 5% for the 10 mg/kg group. Reactivation of cholinesterase activity in blood cells and plasma by means of pralidoxime was very efficient during the first 24 hr after administration of ethion, but was insignificant after 72 hours.