Comparison of ivermectin, oxfendazole and levamisole for use as anthelmintics during the periparturient period in sheep.

Ewes synchronised with progestin impregnated sponges to reduce the spread of lambing were treated during the periparturient period with anthelmintic. The suppression of nematode egg output in faeces was measured in ewes given ivermectin either by subcutaneous injection or orally, or oxfendazole or levamisole orally. Ivermectin and oxfendazole reduced the output of eggs in the faeces of the ewes significantly (P less than 0.05) and the period of suppressed egg output was extended when ivermectin was given by subcutaneous injection. Plasma pepsinogen activity was estimated as a measure of abomasal damage. Pepsinogen values were significantly (P less than 0.001) lower in those animals treated with ivermectin by subcutaneous injection than in control animals. Levamisole showed a poorer response in terms of the output of eggs in faeces than either ivermectin or oxfendazole.