Ruminoreticulum bypass in goats and its possible effect on the ef®cacy of oxfendazole against resistant gastrointestinal parasites

Ruminoreticulum bypass was observed in 9±12-month old Angora goats using video-taped ̄uoroscopy. For experimental purposes, ruminoreticulum bypass was stimulated by yarding animals for 19±24 h before drenching, or by yarding and oral premedication with 2% cobalt sulphate solution. When bypass occurred, 50±100% of the drench was deposited in the abomasum. Ruminoreticulum bypass had no apparent effect on the faecal egg count reduction of benzimidazole resistant Ostertagia spp. following drenching with a standard dose of 5 mg/kg of oxfendazole, although the low frequency of bypass prevented any ®rm conclusions from being made. The importance of ruminoreticulum bypass to the ef®cacy of benzimidazole anthelmintics in goats may have been overemphasised. Published by Elsevier Science B.V.