Sheep Flystrike: Prevention Science and Best Practice

Flystrike prevention in sheep requires understanding fly biology and multi-modal prevention strategies. Science-based prevention dramatically reduces the incidence of this painful condition.

Key Facts

The blowfly strike season in the UK runs from April to October, with peak risk in warm, humid weather
Damp, soiled fleece and wounds are the primary sites for fly egg-laying
Preventive insecticide products have varying durations of action from 8 to 16 weeks
Crutching (removing wool from the breech area) reduces strike risk by 60-80%
Genetic selection for breech-wrinkle-free and plain-bodied sheep reduces susceptibility
The Flystrike Risk Forecasting System (UK) provides regional risk alerts based on weather modeling

Welfare Considerations

Flystrike prevention is a welfare imperative because the condition is both extremely painful and largely preventable. Every case of flystrike that occurs represents a failure of the prevention program to protect that individual animal. Systematic prevention through insecticide treatment timed to the fly season, combined with management practices that reduce fly attractiveness (crutching, wound management), prevents the vast majority of cases. Farmers who take prevention seriously prevent real, intense suffering across their flock.

What You Can Do

Use the Flystrike Risk Forecasting System to time preventive insecticide application optimally
Crutch ewes before the fly season to reduce soiling and fly attractiveness in the breech area
Apply preventive insecticide to all sheep before the peak risk period, covering the most vulnerable areas
Inspect sheep daily during high-risk periods — focus on the breech, back, and shoulders
Treat any wounds promptly to reduce their attractiveness to egg-laying flies
Consider genetic selection toward plain-bodied breeds less susceptible to flystrike in high-pressure areas