What is mulesing?
Mulesing involves cutting a crescent-shaped slice of skin from each side of the buttock area; the usual cut on each side is 5 – 7cm in width and extends slightly less than halfway from the anus to the hock of the back leg in length. Skin is also stripped from the sides and the end of the tail stump. This surgical procedure is usually done without any anaesthetic. The large scars left after mulesing take several weeks to heal and are susceptible to infection and flystrike.
Whilst mulesing can reduce (but not eliminate) the risk of flystrike to the treated area, it can also increase the risk due to flies being attracted to the open wounds that take up to 4 weeks to heal.
The large scars left after mulesing take several weeks to heal and are susceptible to infection and flystrike 
Why do farmers mules their sheep?
Farmers mules the sheep in their care in an attempt to reduce the incidence of flystrike. Whilst there are other methods of reducing flystrike, due to the size of their flocks that often run into the thousands, this can be costly to the farmers in regards to money and time. They are, therefore, usually reluctant to explore the alternatives.