The plasma concentration profiles of oxfendazole (OFZ), fenbendazole (FBZ) and FBZ sulphone (FBZ.SO2) were measured followed intraruminal administration Of OFZ at 5 mg kg-1 to Merino weaners fed either dry forage or grazed on pasture lucerne clover. Plasma concentrations of OFZ and FBZ were significantly lower in sheep given the dry forage.