The Can-Vet Back Rubbing Solution cattle insecticide is formulated for use with beef, lactating and non-lactating dairy cattle. The ready-to-use formula is made for back-rubbing devices to easily protect your herd from gnats, horn flies, black flies and face flies. This back rub insecticide lasts up to three weeks, and one back rub device can protect 35 to 45 cows. Ontario Class 4 pesticide. Flammable. If irritation occurs, discontinue use.