Blowfly Strike in Sheep: Prevention and Emergency Welfare
Blowfly strike (myiasis) is one of the most severe acute welfare emergencies in sheep farming, caused by fly larvae eating into living tissue, requiring urgent intervention.
Key Facts
- Lucilia sericata (greenbottle) is the primary blowfly causing strike in the UK
- Eggs are laid on soiled or damaged fleece; larvae hatch and burrow into skin within hours
- Affected sheep experience intense pain and rapid deterioration if untreated
- Clipping soiled wool, removing larvae, and topical insecticide treatment saves lives
- Prevention through insecticide application, shearing, and daggings removal is essential
Welfare Considerations
Blowfly strike represents one of the most acute welfare crises possible in sheep management. The rapid escalation from egg-laying to larval penetration means welfare deterioration can occur within 12-24 hours. Affected sheep show behavioral indicators of extreme pain including separation, restlessness, and continuous biting at affected areas. Tissue damage can be extensive, with larvae penetrating deeply into muscle. Emergency treatment requires removing all larvae, cleaning wounds, applying insecticide, and providing veterinary care including antibiotics and pain management. Prevention through routine monitoring, prompt dagging, timely shearing, and insecticide application is far superior to treatment.
What You Can Do
- Check sheep at least daily during the fly season (April-October)
- Remove soiled wool (daggings) from around the tail as part of routine management
- Apply preventive insecticide treatment at the start of the fly season
- Act immediately when strike is detected — every hour delay worsens welfare
- Euthanize severely affected animals when treatment would cause more suffering than it relieves