Elanco CyLence® Pour-OnCyLence Pour On, a pyrethroid insecticide, works to control horn flies, face flies, and biting and sucking lice on beef and dairy cattle, including lactating. Ready to use solution no mixing required. Can be used any time of year. Only a small amount of product is required per treatment. No meat or milk withdrawal requirements. Can be used on cattle of any age or size. Convenient, versatile and effective. Apply the required amount of product directly