Flumethrin distribution on cattle haircoat after pour-on application

Abstract

By means of chemical analysis, the distribution behaviour of flumethrin was determined in the haircoat of cattle following topical pour-on application. Flumethrin was applied at 1 mg active ingredient 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 µg 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, 23.0-1.0 and 44.0-0.9 µg 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 µg 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.