Zerofen 2.5% Dosage and administration Assess bodyweight as accurately as possible before calculating the dosage. Shake container before use. Sheep Give as an oral drench at the rate of 5 mg fenbendazole per kg bodyweight (1 ml per 5 kg bodyweight). Sheep Bodyweight Dose Up to 15 kg  3 ml 16–25 kg  5 ml 26–35 kg  7 ml 36–50 kg 10 ml 51–65 kg 13 ml 66–75 kg 15 ml Over 75 kg give 2 ml per 10 kg.   Cattle Give as an oral drench at the rate of 7.5 mg fenbendazole per kg bodyweight (3 ml per 10 kg bodyweight). Cattle Bodyweight Dose  50 kg  15 ml 100 kg  30 ml 150 kg  45 ml 200 kg  60 ml 250 kg  75 ml 300 kg  90 ml 350 kg 105 ml Over 350 kg give 15 ml per 50 kg.