BOVINE TOLERANCE FOR MALATHION: AN EXPERIMENT IN RELATION TO A CASE REPORT

Three purebred Shorthorn cattle were tested for susceptibility to malathion toxicity. They were subjects of a case report in which symptoms had been interpreted as organophosphate poisoning following the recommended pesticidal treatment for lice. Animals were experimentally overdosed with a malathion spray at three-week intervals. Individual treatments exceeded 20 times and cumulative treatments 50 times the recommended dose. No clinical symptoms could be detected at any time during or after treatment. A depression of approximately 20-30 per cent in blood cholinesterase was the only subclinical effect of toxicity observed. Variations in body weight remained within the range expected for mature animals on a maintenance diet.