Sheep Flystrike: Prevention, Detection and Treatment

Blowfly strike is one of the most painful and distressing conditions affecting sheep worldwide. Effective prevention and early detection are critical to preventing unnecessary suffering.

Key Facts

Blowfly strike causes maggot infestation of living sheep tissue, typically beginning around the breech
An estimated 80% of UK sheep farms experience at least one flystrike case annually
Affected sheep can die within 48-72 hours if untreated — maggots can penetrate through to underlying tissue
The smell of soiled wool and wounds attracts blowflies — dagginess management is a key preventive measure
Insecticide treatments (organophosphates and synthetic pyrethroids) provide 8-16 weeks of protection
Breeding for reduced dag scoring and breech wrinkle has produced flystrike-resistant lines without mulesing
Electronic monitoring systems can detect the behavioural changes of flystruck sheep before visual detection

Welfare Considerations

Flystrike causes one of the most severe welfare states encountered in farm animal practice. The rapid progression from initial strike to deep tissue infestation, accompanied by toxin absorption from maggot secretions, causes a constellation of pain, systemic illness and distress that can be fatal within days. The welfare imperative is therefore on prevention and early detection. Regular visual inspection of high-risk areas — breech, wounds, feet — particularly during warm, humid weather when fly populations peak, is the most critical management practice. Preventive insecticide treatment in high-risk periods and selective breeding for traits that reduce flystrike susceptibility offer systemic solutions. The pain and distress of advanced flystrike makes rapid euthanasia of severely affected animals sometimes the most welfare-positive response.

What You Can Do

Inspect sheep daily during warm weather — pay particular attention to the breech and any wounds
Apply appropriate preventive insecticide treatments during high-risk periods according to veterinary guidance
Breed for reduced dag scoring and breech wrinkle as long-term structural prevention without mulesing
Act immediately on any detected flystrike — early treatment prevents escalation to life-threatening infestation