Welfare of Animals in Sheep Fly Strike Prevention

Fly strike — blowfly larvae burrowing into living sheep tissue — causes intense suffering and death if untreated, and prevention welfare tradeoffs involve mulesing versus alternative methods.

Key Facts

Blowfly strike affects approximately 3% of UK sheep annually and causes significant mortality
Merino sheep with skin folds are particularly vulnerable because folds retain moisture that attracts flies
Mulesing — removing skin folds — prevents fly strike but causes acute pain without anesthesia
The Sheep Industry Task Force found flystrike causes over 14 million Australian dollars in annual losses
Clip-on breech covers, breeding for plain-bodied sheep, and chemical prevention are effective alternatives

Welfare Considerations

Fly strike welfare involves a genuine tradeoff: the suffering caused by blowfly larvae in unprotected sheep is extreme and often fatal; mulesing prevents this suffering at the cost of acute pain during the procedure. Neither outcome is welfare-neutral. The welfare-optimal approach depends on risk level and alternatives available: in high-risk environments without alternative prevention, mulesing with proper pain management may prevent more total suffering; in lower-risk environments, alternative prevention methods avoid both harms.

What You Can Do

Support breeding programs selecting for plain-bodied merino sheep that do not require mulesing
Advocate for mandatory pain relief protocols when mulesing is performed
Choose wool from certified mulesing-free producers where fly strike alternatives are feasible
Donate to research programs developing effective non-mulesing fly strike prevention for high-risk environments