ANALYTICAL DETERMINATION OF THE DISTRIBUTION OF FLUMETHRIN ON THE BODY-SURFACE OF CATTLE FOLLOWING TOPICAL POUR-ON APPLICATION

By means of chemical analysis, the distribution behaviour of flumethrin was determined in the hair coat of cattle following topical pour-on application. Flumethrin was applied at 1 mg active ingredient (a.i.) kg-1 body weight along the backline of cattle. It was demonstrated that this compound could be recovered from all hair samples taken on Day 1 following application from dorsal, lateral. ventral and distal body regions in concentrations ranging from 670 to 1-mu-g a.i. g-1 hair, depending on the distance from the site of application. On Days 3, 5 and 10 after treatment, the corresponding concentrations were 125.0-1.5, 2'3.0-1.0, and 44.0-0.9-mu-g a.i. g-1 hair, respectively. When correlating these values to the body surface of cattle, it is evident that on all sample days and body regions, a concentration of more than 0.01-mu-g a.i. cm-2 body surface was present. This amount of active substance is sufficient for effective acaricidal action, as shown by laboratory and field data.