Mulesing is the removal of strips of wool-bearing skin from around the breech (buttocks) of a sheep to prevent the parasitic infection flystrike (myiasis). The wool around the buttocks can retain feces and urine, which attracts flies. The scar tissue that grows over the wound does not grow wool, so is less likely to attract the flies that cause flystrike. Mulesing is a common practice in Australia for this purpose, particularly on highly wrinkled Merino sheep.
Mulesing is considered by some to be a skilled surgical task. Mulesing can only affect flystrike on the area cut out and has no effect on flystrike on any other part of the animal's body.
Mulesing is a controversial practice. The National Farmers Federation of Australia says that "mulesing remains the most effective practical way to eliminate the risk of 'flystrike' in sheep" and that "without mulesing up to 3,000,000 sheep a year could die a slow and agonising death from flystrike". The Australian Veterinary Association (AVA) "recognises the welfare implications of mulesing of sheep. However, in the absence of more humane alternatives for preventing breech strike, the AVA accepts that the practice of mulesing should continue as a sheep husbandry procedure". The AVA also supports the use of analgesics and the accreditation of mulesing practitioners. The Australian Royal Society for the Prevention of Cruelty to Animals accepts mulesing when the risk of flystrike is very high, when it is done properly, and even then only as a last resort. The animal rightsorganisation PETA strongly opposes mulesing, says the practice is cruel and painful, and that more humane alternatives exist, and claim that sheep can be spared maggot infestation through more humane methods, including special diets and spray washing.
In July 2009, representatives of the Australian wool industry scrapped an earlier promise, made in November 2004, to phase out the practice of mulesing in Australia by 31 December 2010. Mulesing is being phased out in New Zealand.