Anthelmintic efficiency related to strategic control schemes for helminthiasis in sheep

A comparison was made of the effects on worm egg output from groups of sheep treated with either thiabendazole or levamisole at 3 dose rates in different weight categories of weaned lambs. Neither thiabendazole at 79.8 mg/kg nor levamisol at 12.8 mg/kg completely prevented worm egg output by treated sheep. Over all dose rates thiabendazole was significantly more effective than levamisole. The data indicated that dose rates may need to be increased for use in strategic control schemes for helminthiasis.