Résumé
The plasma and fecal concentrations of eprinomectin were determined in cattle following topical administration at adose rate of 0.5 mg kg21. The maximum plasma concentrations of 12.24 ng ml21 occurred 2 d after administration, and eprinomectinremained detectable in plasma 29 d after administration (0.10 ng ml21). The maximum dung concentration of 350 ng g21 wasobserved 3 d after administration and thereafter for at least 29 d (4 ng g21). The amount of drug recovered in dung during thisperiod was 20.50% 6 4.31% of the total administered dose. The effects of eprinomectin against the nontarget dung-feeding DipteraNeomyia cornicina was assessed under laboratory conditions. Feces voided by cattle treated with eprinomectin were associatedwith high larval mortality during the first 12 d after treatment, with null emergence until day 7. The no-observed-effect concentrationfor N. cornicina was estimated to be close to 7 6 5 ng g21.