AiM-A Abamectin VetCaps are scientifically developed gelatin capsules designed to be used exclusively with the VetGun. Each AiM-A capsule contains an abamectin formula (a macrocyclic lactone in the avermectin family), and is an Environmental Protection Agency (EPA)-registered insecticide for use on beef cattle and non-lactating dairy cattle. AiM-A (abamectin) VetCaps can be used in rotation with AiM-L VetCaps (lambda-cyhalothrin) as an effective in-season "rotation program" to combat horn flies resistance.