Altosid IGR XRB for Horn Fly Control BolusesAltosid IGR XRB for Horn Fly Control 25 Boluses Break the horn fly life cycle at the source with (S) methoprene. This innovative bolus relies on the animal to deliver the active ingredient directly to the manurewhere horn flies lay their eggs. Once administered, the bolus settles in the cows rumen and gradually dissolves, providing consistent release of (S) methoprene for up to 195 days. By interrupting the development of horn fly pupae into biting