Mulesing — the surgical removal of skin around a Merino sheep's breech — is performed to prevent flystrike. Its welfare costs have driven research into alternatives and retailer commitments to phase it out.
Mulesing is a significant welfare procedure that causes genuine acute pain and post-operative distress. The industry justification is that the procedure prevents a worse welfare outcome — flystrike, in which blowfly larvae consume living tissue causing extreme suffering. This is a genuine welfare trade-off, but the availability of alternatives makes continuation of mulesing without pain relief increasingly indefensible. The welfare-optimal approach involves transitioning flocks to selective-bred plain-bodied lines that require no mulesing, using pain relief for all current mulesing procedures, and applying effective flystrike prevention management in the interim. Consumer and retailer pressure has been instrumental in accelerating industry commitment to mulesing reform.