Residues in tissues of sheep following oral dosing and tip spraying with³²p-labelled ronnel

Residues in milk, blood, urine, and faeces of cows after treatment with32P-labelled fenchlorphos “pour-on”

“…When administered either orally or dermally the compound kills ectoparasites such as cattle grubs, screw worms, and flies (McGregor & Bushland 1957;Hopkins & Knapp 1963;Graham et al 1959;Oehler et al 1970;Roberts 1959). Plapp & Casida (1958), Millar (1965), andMcDuffie (1966) found that fenchlorphos accumulated in the fatty tissues of animals treated with the insec• ticide. Millar (1965) showed that 2 days after a single oral dose of 50 mg/kg, the highest concentration of fenchlorphos in a sheep was 35 p.g/g in the perirenal fat, with somewhat less in the omental and subcutaneous fat.…”

“…Plapp & Casida (1958), Millar (1965), andMcDuffie (1966) found that fenchlorphos accumulated in the fatty tissues of animals treated with the insec• ticide. Millar (1965) showed that 2 days after a single oral dose of 50 mg/kg, the highest concentration of fenchlorphos in a sheep was 35 p.g/g in the perirenal fat, with somewhat less in the omental and subcutaneous fat. The biological half-life of fenchlorphos in subcutaneous fat was found to be about 5 days.…”