Summer flies cause significant and often underestimated welfare harm to cattle through direct biting, annoyance, and in severe cases strike and myiasis requiring urgent treatment.
The cumulative welfare impact of summer flies on cattle is substantial. Constant biting prevents normal resting and feeding behaviour, causes chronic low-level pain, and spreads infectious diseases. Fly myiasis in wounds causes acute severe pain. The welfare cost of inadequate fly control is often measured only in production terms rather than animal suffering terms, leading to under-investment in management.