Sheep Flystrike: Prevention and Welfare

Flystrike (blowfly strike) is one of the most acutely painful conditions in sheep. Blowfly larvae burrow into living tissue, causing rapid and catastrophic tissue destruction.

Key Facts

Flystrike is caused primarily by Lucilia sericata (green bottle fly) and Calliphora species in Europe and Australia
Flies are attracted to moist, soiled, or wounded skin — particularly around the breech and tail
Larvae hatch within 12-24 hours and begin feeding on living tissue immediately
Affected sheep can die within 3-5 days if untreated, from toxemia and protein loss
Prevalence can reach 1-3% of flocks annually in high-risk regions and seasons
Prevention options include prophylactic insecticide treatments, crutching, and mulesing in Australia

Welfare Considerations

Flystrike causes intense suffering — larvae release proteolytic enzymes that liquefy living tissue, causing extreme pain and toxemia. Affected sheep show characteristic postures (twisting, biting at affected area), reduced grazing, and rapid deterioration. Detection requires regular inspection during the fly season (daily in high-risk periods). Treatment with insecticide, wound cleaning, and antibiotics is effective if caught early. Prevention using appropriate prophylactic products significantly reduces flock suffering during fly season.

What You Can Do

Inspect sheep at least daily during fly season, especially around the breech, tail, and any wounds
Apply preventive insecticide treatments (cyromazine, dicyclanil) at the start of fly season
Crutch (clip) wool from the breech area to reduce soiling and fly attraction
Treat struck sheep immediately with insecticide, wound treatment, and analgesic pain relief