uraMectin Paste Horse Wormer (1.87% Ivermectin) controls bots, large strongyles, small bloodworms, ascarids (roundworms), threadworms, pinworms, hairworms, lungworms, and large mouth stomach worms. Ivermectin wormer is proven safe for pregnant mares, breeding stallions, and any age foal. Each syringe will worm up to a 1250 lb. horse. Syringes are adjustable in 250 lb. increments.