TOXICITY OF METHOMYL FOLLOWING INTRAVENOUS ADMINISTRATION IN THE HORSE

Methomyl (S-methyl-N-((methylcarbamoyl)oxy)thioacetimidate) toxicity w as studied In horses using iv dosages from 0.01 to 3.0 mg/kg. Doses of 1-3 mg methomy l/kg produced increased GI motility and respirations, facial fasiculations, salivation, lacrimation and convulsions. The onl y effect at 0.5 mg/kg was increased Gl sounds in 1/4 horses. This exte nsively used crop insecticide had been associated with episodes of mor bidity and mortality and led to speculation that it was extremely pote nt to the horse. This was not supported by these clinical studies.