JustiFLY Liquid Feed Add Pack is a nutritional supplement containing the insect growth regulator diflubenzuron, formulated for mixing directly into liquid cattle feed. Once cattle consume the treated liquid feed, the active ingredient passes through the digestive tract and into the manure, where it works to prevent the development of horn fly, stable fly, house fly, and face fly larvae. The pack is intended for continuous feeding throughout fly season as part of a liquid feed program for beef and dairy cattle. It is added directly to a liquid feeder during tank charging, requiring no separate mixing equipment or animal handling. The product is formulated to leave no residue in treated animals and carries no associated withdrawal period. It is packaged as a dry additive pack designed for on-farm liquid feed systems.