Residues of trichlorphon (neguvon) in milk after dermal application to cattle

The probability that trichlorphon may be used to control warbles in dairy cattle has raised the question of whether milk from treated animals will contain any harmful residues. Results from bioassays show that, when applied as a dermal wash at a maximum of 2 pints of 2% solution or 1 pint of 4% solution per animal, the level of insecticide present in the milk does not at any time exceed 0.4 p.p.m. and if more than 6 h. has elapsed after treatment, the level is generally about 0.1 p.p.m. It is considered that this level does not present a hazard to any consumer. The presence of open warble holes does not materially affect the amount of trichlorphon secreted in the milk.