Livestock

Sheep Blowfly Strike Prevention: Welfare Priorities 2026

Blowfly strike is one of the most significant and preventable welfare emergencies in sheep farming, caused by blowfly larvae feeding on living tissue and requiring urgent preventive action.

Key Facts

Blowfly strike kills an estimated 1% of UK sheep annually and affects up to 80% of flocks
The primary species responsible is Lucilia sericata, the green bottle fly
Strike most commonly starts around the breech, tail and wounds but can spread across the body
Affected sheep suffer extreme pain and distress from larval tissue destruction

Welfare Considerations

Blowfly strike causes severe pain and distress and is rapidly fatal without treatment. Prevention is far more humane than treatment and includes using preventive insecticides, dagging to remove soiled wool, breeding for tighter-skinned breeds, and monitoring flock risk factors. Faecal soiling from worm burdens dramatically increases strike risk.

What You Can Do

Apply preventive insecticide treatments such as organophosphates or pour-on products at appropriate times
Dag or trim wool around the breech before the main fly season
Maintain effective worm control to reduce faecal soiling that attracts blowflies
Check sheep at least twice daily during high-risk weather conditions in summer