EFFICACY OF ABAMECTIN AGAINST ECTOPARASITES OF CATTLE

Four trials, using 48 European breed cattle, were conducted to evaluat e the efficacy of abamectin against the louse species Linognathus vitu li, Haematopinus eurysternus and Damalinia bovis and against the mange mites Sarcoptes scabiei var bovis and Psoroptes ovis. Animals were al located by restricted randomisation based on parasite counts to treatm ent with abamectin at a dose of 200 mug/kg given subcutaneously or to an untreated control group. Ectoparasites were counted before treatmen t and at weekly intervals thereafter for eight weeks. L vituli, H eury sternus and S scabiei var bovis were eliminated (P<0.05) by day 7 afte r abamectin treatment. An efficacy of more than 99 per cent was record ed against P ovis mange mites. The biting louse D bovis was not contro lled. Abamectin treatment increased the weight gain of cattle infested with ectoparasites.