CHARACTERIZATION OF FENVALERATE RESIDUES IN DAIRY-CATTLE AND POULTRY

The chemical nature and magnitude of [C-14]fenvalerate residues in the milk, egg, fat, liver, kidney, and muscle tissues in dairy cows and laying hens were examined after extended periods of oral exposure. Dosing levels represented 2 to greater than 100 times the maximum dietary burden. Rapid absorption and distribution of the unchanged fenvalerate residues in the milk (primarily in the cream fraction), egg yolk, body fat, and muscle tissues were observed. Extensive degradation/metabolism of [C-14]-fenvalerate (labeled with C-14 at the chlorophenyl and/or phenoxyphenyl moiety) was observed in the liver and kidney tissues. Tissue residues were also shown to dissipate rapidly from the test animals when treated diets were replaced with uncontaminated feeds. The overall metabolic pathway of fenvalerate, mainly via ester cleavage, is consistent among dairy cow, laying hen, and other laboratory animals.