Sheep Flystrike Prevention: A High-Stakes Welfare Challenge in Wool Production

Flystrike — the infestation of living sheep with blowfly larvae — causes extreme suffering and rapid death, and its prevention is one of the most demanding welfare responsibilities in sheep farming worldwide.

Key Facts

Flystrike occurs when blowflies (particularly Lucilia sericalis in the UK) lay eggs in moist, soiled, or wounded wool, and the hatching larvae consume living tissue
Affected sheep can die within days from toxaemia and secondary infection if not treated promptly
Clinical signs include restlessness, biting at wool, a characteristic odour, and dark stained fleece patches — often missed until advanced
Around 80% of UK flystrike cases affect the breech (around the tail and hindquarters), where faecal soiling provides ideal conditions for fly strike
Preventive approaches include dagging (removing soiled wool), chemical preventives (organophosphates and dicyclanil), and careful monitoring during high-risk periods
Mulesing — removing skin folds around the breech — is practised in Australia as a permanent prevention method but is highly painful and increasingly rejected internationally
Climate change is extending the flystrike season in the UK and other cool climates, increasing the risk burden on sheep farmers

Welfare Considerations

Flystrike causes some of the most intense and rapid suffering of any livestock disease. Larvae consume living flesh within hours of hatching, causing wounds that can be extensive before discovery. The psychological and physical suffering of an affected animal — being consumed alive — is extreme. Prevention is far preferable to treatment, but prevention requires vigilant daily monitoring during summer months, knowledge of risk factors, and willingness to use effective preventive treatments. The scale of the problem — hundreds of thousands of UK sheep affected annually — makes flystrike one of the highest-priority welfare challenges in sheep farming.

What You Can Do

Learn to recognise the early signs of flystrike if you manage sheep or spend time around sheep farms
Support farmers using evidence-based flystrike prevention programs including dagging and chemical preventives
Advocate for flystrike monitoring to be included in sheep welfare auditing protocols
Support research into alternative prevention methods that reduce reliance on organophosphate chemicals
Oppose mulesing as a flystrike prevention method and support breed selection and management alternatives
Report visibly flyblown sheep to the farmer or local authority if encountered — untreated flystrike is a welfare emergency
Buy wool products from producers who demonstrate responsible flystrike prevention management