IVOMEC Pour-On is a topically applied dewormer for the control of internal and external parasites in cattle. It's labeled for the control of gastrointestinal roundworms, lungworms, grubs, horn flies, sucking and biting lice, and sarcoptic mange mites. Ivomec Pour-On controls horn flies for up to 28 days after dosing. It works by interrupting nerve impulses in the parasite, thereby paralyzing and killing the parasite. Cattle must not be treated within 48 days of slaughter. Because a withdrawal time in milk has not been established, do not use in female dairy cattle of breeding age. Apply along the topline in a narrow strip from withers to tailhead. Dosage: 1 ml per 22 lbs of body weight.