Sheep Fly Strike Prevention and Welfare

Blowfly strike is one of the most painful and welfare-significant conditions affecting sheep. Prevention is far more effective than treatment of established cases.

Key Facts

Blowfly strike (myiasis) occurs when blowflies lay eggs on soiled or wounded fleece, with maggots hatching within hours
Lucilia sericata is the primary causative species in the UK and Australia
Affected sheep experience extreme pain, tissue destruction, and can die within days if untreated
Predisposing factors include damp fleece, dag (dung-soiled wool), skin wounds, and foot rot
Prevention methods include insecticide treatments, wool management, and genetic selection for resistance
Mulesing - surgical removal of breech skin - is controversial due to acute pain and animal welfare concerns
Alternative breech modification approaches and selective breeding offer paths away from mulesing

Welfare Considerations

Fly strike is one of the most acutely painful conditions in veterinary medicine. Maggots produce proteolytic enzymes that liquefy tissue, causing severe pain, shock, and rapid deterioration. Even mild cases cause intense discomfort for affected animals. The preventable nature of most cases makes strike welfare failures particularly significant - farmers who neglect prevention knowing the consequences create avoidable suffering at scale.

What You Can Do

Apply preventive insecticide treatments at appropriate times based on regional fly season forecasting
Keep sheep free of dag by managing nutrition to prevent scouring and dagging when needed
Check sheep daily during high-risk periods - early morning is most effective
Identify and treat any wounds, foot rot, or other conditions that predispose to strike
Consider breeding programs selecting for breech cover or bare breech traits that reduce strike risk
Have a treatment plan ready including wound wash, maggot removal protocol, and veterinary contact for severe cases
Report any suspected strike immediately and isolate affected animals for treatment