Safe-guard Medicated Dewormer For Beef Cattle (20% Protein Block. For the removal and control of lungworms, stomach worms and intestinal worms. Safe-Guard® (fenbendazole) 20% Protein Deworming Block (Medicated) is designed for deworming pastured cattle by feeding these medicated blocks for three (3) days only as the sole source of salt. It is essential to establish full cattle adaptation to supplemental block feeding prior to treating cattle with Safe-Guard® 20% Protein Deworming Block (Medicated). Treats 11 - 1,000 lb animals. Do not use in dairy cattle of breeding age. Cattle must not be slaughtered within 16 days following last treatment. Under conditions of continuous exposure to parasites, retreatment may be needed after 6 to 8 weeks. Contains 750 mg fenbendazole per lb.