Sheep Blowfly Strike Prevention and Management

Blowfly strike in sheep causes intense suffering and is a leading welfare problem in UK sheep farming. Prevention through shearing, dagging, and insecticide application is far preferable to treatment.

Key Facts

Blowfly strike kills around 80,000 sheep annually in the UK, with many more suffering before treatment
Lucilia sericata (greenbottle fly) is responsible for the majority of UK sheep blowfly strikes
The primary risk factors are soiled fleece around the tail (dagginess), wounds, and foot rot lesions
Maggots can penetrate the skin within hours of egg hatching, causing severe tissue damage
Preventive treatments including diazinon, cypermethrin, and dicyclanil have different efficacy and withdrawal periods
Earlier shearing and regular dagging (removing soiled wool) significantly reduce strike incidence

Welfare Considerations

Sheep blowfly strike causes intense, prolonged suffering as maggots consume living tissue. The smell of affected animals and the speed of tissue destruction mean advanced cases involve extreme welfare compromise. Yet this suffering is largely preventable — the combination of timely shearing, dagging, and preventive insecticide application can dramatically reduce strike incidence on managed flocks. Stockmanship quality is directly correlated with blowfly welfare outcomes.

What You Can Do

Shear sheep before the main blowfly season begins — typically April to June in the UK
Dag sheep regularly throughout the year, particularly those prone to loose faeces
Apply preventive blowfly treatments at appropriate timing based on local forecast services
Inspect sheep at least twice daily in high-risk weather conditions (warm, humid, thundery)
Treat any struck sheep immediately — remove maggots, clean wounds, and apply appropriate insecticide
Consult your vet or AHDB guidance on appropriate blowfly prevention products for your flock