Horn flies (Haematobia irritans) are the most economically damaging cattle parasite in North America, with individual cattle receiving 200–4,000 bites daily during peak season. Blood loss, pain, and behavioural disruption — including bunching, increased movement, and reduced grazing time — directly compromise welfare. Economic losses exceed $1 billion annually in the US from production impacts. Control methods include insecticide ear tags, pour-on products, back rubbers, and biological controls. Insecticide resistance is widespread across pyrethroid and organophosphate classes, limiting management options. Integrated pest management combining multiple control tactics reduces resistance pressure. Genetic selection for fly resistance and the use of dung beetles as biocontrol agents represent welfare-positive, sustainability-compatible approaches.