Mulesing is a procedure performed on some breeds of sheep, primarily Merino sheep, to reduce the risk of a potentially fatal condition called flystrike.

What is flystrike?

Flystrike occurs when certain species of blowflies lay eggs in the moist folds of a sheep's skin. When the eggs hatch, the maggots feed on the sheep's flesh, causing severe pain, infection, and, if untreated, death.

Australia's climate is particularly favourable for blowflies, especially in warmer and wetter regions, making flystrike one of the most significant animal welfare challenges faced by sheep producers.

What is mulesing?

Mulesing involves removing strips of wool-bearing skin from around a lamb's breech (the area around the tail and buttocks). As the area heals, smooth scar tissue forms, reducing skin wrinkles where moisture and manure can accumulate. This makes the sheep less attractive to blowflies and significantly lowers the risk of flystrike.

The practice was developed by Australian wool grower John W. H. Mules in the 1920s.

Why has mulesing been used in Australia?

Australia produces a large proportion of the world's fine Merino wool. Merino sheep were selectively bred for their abundant wool production, which often results in wrinkled skin. While these wrinkles increase fleece production, they can also create ideal conditions for flystrike.

Historically, mulesing was adopted because it:

Significantly reduces the incidence of breech flystrike
Decreases sheep mortality
Reduces the need for repeated chemical treatments
Provides long-term protection throughout the sheep's life

Why is it controversial?

Animal welfare organisations have raised concerns because mulesing is painful and invasive. Although pain relief products are now widely available and increasingly used, many consumers and welfare groups continue to advocate for alternatives.

The controversy has led to growing demand for:

Non-mulesed wool
Sheep bred with fewer wrinkles
Improved management practices
Alternative flystrike prevention methods

What alternatives are being used?

Many Australian wool growers are transitioning toward non-mulesed systems through:

Selective breeding for plainer-bodied sheep
Strategic crutching and shearing
Improved parasite and fly management
Use of insecticides and preventative treatments
Enhanced animal husbandry practices

As a result, the proportion of non-mulesed wool available in Australia continues to grow.

What does this mean for knitters and wool consumers?

Today, wool may be marketed as:

Mulesed wool – from sheep that have undergone mulesing
Non-mulesed wool – from sheep protected through alternative methods
Ceased mulesing – from farms that have stopped the practice entirely

Many yarn companies now provide transparency about their sourcing so consumers can make informed choices based on their personal preferences and values.

In summary, mulesing was developed in Australia as a highly effective method of preventing the serious welfare issue of flystrike in Merino sheep. While it has protected millions of sheep from flystrike, concerns about animal welfare have driven the industry toward breeding, management, and husbandry alternatives that reduce reliance on the practice.