Mulesing — surgical removal of skin around the breech of Merino sheep to prevent flystrike — is a painful procedure that has driven major welfare debates in Australian wool production.
Mulesing causes significant acute pain — lambs show pain responses including altered gait, posturing, and reduced activity for days following the procedure. The welfare justification is the prevention of flystrike, which is itself a severe welfare problem: flystrike causes tissue destruction, pain, and rapid deterioration in untreated animals. However, the choice is not binary between mulesing and flystrike: genetic selection for plain-bodied sheep that are less susceptible to flystrike, combined with strategic chemical protection and monitoring, can manage flystrike risk in non-mulesed flocks. Pain relief provision for mulesing, where the procedure continues, is mandatory in New Zealand and recommended in Australia, but uptake is variable. The long-term welfare-positive direction is toward genetic solutions that eliminate the flystrike susceptibility rather than the painful management of its symptoms.