Mulesing is a painful surgical procedure performed on Merino sheep to prevent flystrike, and its welfare implications have driven significant industry debate.
Mulesing involves real and significant acute pain for the sheep subjected to it. The procedure is typically performed without anesthesia on lambs weeks to months old, causing tissue damage that takes weeks to heal. The justification is prevention of flystrike, which causes its own severe suffering through larval infestation of living tissue. This creates a genuine welfare dilemma - mulesing causes certain, acute pain to prevent the risk of potentially worse pain from flystrike. However, New Zealand's experience demonstrates that mulesing can be largely eliminated through a combination of selective breeding for less susceptible fleece characteristics, strategic timing of shearing, and use of effective topical preventive treatments. The existence of alternatives makes continued mulesing without pain relief ethically unjustifiable.