Mulesing — surgically removing skin around the breech of Merino sheep to prevent flystrike — is a painful procedure that has driven significant animal welfare debate and campaigns for alternatives in Australia.
Mulesing causes acute pain during the procedure and prolonged post-operative pain lasting days to weeks. Lambs subjected to mulesing without analgesia show elevated stress indicators including cortisol elevation, altered gait, and reduced feeding behavior for an extended period. The welfare calculus involves comparing the acute pain of mulesing against the potential chronic pain of flystrike — which causes catastrophic tissue destruction and often death. New Zealand's successful transition to non-mulesed production demonstrates that alternatives are commercially viable. Pain relief at mulesing is achievable and mandated in some states; the availability of analgesics means that while mulesing itself remains controversial, performing it without pain relief is indefensible given evidence of suffering and the existence of effective analgesics.