Stage 6 Agriculture – Animal welfare and ethics

Exploring the history, purpose and science related to mulesing

Exploring the history, purpose and science related to mulesing provides students with an opportunity to study Plant/Animal Production content in the Stage 6 Agriculture HSC course.

This unit of work explores the husbandry operation of mulesing within the context of an integrated pest management program.

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Understanding mulesing

Fifty years ago, the husbandry operation of mulesing was considered routine by most wool producers in Australia. Now in the 21st century the practice is seriously questioned, and considerable time and resources are being used to find ways to continue to produce high-quality wool in Australia sustainably, humanely, and efficiently, without the need to mules.

Exploring the history, purpose and science related to mulesing provides students with an opportunity to study Plant/Animal Production content in the Stage 6 Agriculture HSC course.

Syllabus content

Animal pests and diseases

  • Investigate the complex interaction between the problem organism, the host, and the environment for one animal disease.
  • Research using secondary sources an IPM program for an animal production system.
  • Evaluate an IPM program, naming the target organism and the animal host.

Animal ethics and welfare

  • Discuss the factors that should be considered when carrying out a particular husbandry practice to reduce the negative welfare impacts to the animal including use of appropriate equipment, skill of the operator, timing of the animal practice, management of the animals after completion of practice.
  • Discuss one ethical issue relevant to an animal production system such as mulesing, live export, battery egg production, use of farrowing crates.
  • Investigate animal welfare legislation for a specific farm animal and discuss the implications of the legislation for the relevant production system.

What is mulesing?

Mulesing is a husbandry practice carried out on sheep that involves cutting crescent-shaped flaps of skin from around a lamb's breech and tail. When the wound heals, the area scars, creating a bare, smooth area of skin around the tail which has no folds or wrinkles. This means the skin remains cleaner and drier than if not mulesed.

Why is mulesing done?

The purpose of mulesing is to make sheep less susceptible to flystrike in the breech area. Sheep blowflies lay eggs in warm, moist areas of the sheep’s body. These areas are commonly in skin wrinkles, where there are dags or fleece rot, or on the sites of injuries. Mulesing removes the wrinkles from the breech area, making this site on the animal less attractive to the flies.

Is mulesing carried out on all sheep?

Typically, mulesing is carried out on Merino sheep. This is because Merinos have particularly wrinkly skin, a feature that has been selected for when breeding Merinos over the years to increase skin surface area and therefore amount of wool per animal. With wrinkly skin comes woolly wrinkles and folds in their skin around the tail and breech area which often becomes moist with urine and contaminated with faeces.

Blowflies are attracted to the moist area, and lay eggs in the area which hatch into larvae (maggots) within 12-24 hours and then proceed to feed off the flesh of the sheep. This is called flystrike, and it can be fatal if not treated.

Image: Flystrike can cause severe health problems in sheep.

Flystrike costs the Australian wool and sheep meat industries in excess of $200 million per year.


Originally the Australian Merino sheep were quite plain-bodied. But late in the 1870s, Vermont Merinos were introduced to Australia from Vermont in the USA. These Vermont Merinos were incredibly wrinkly, with folds of skin from head to toe.

Image: Vermont Merinos

Prior to the introduction of the Vermont Merino, Australian Merinos were called smooth-bodied. Their skin fitted relatively tightly over their skeleton. In contrast, Vermont Merinos were incredibly wrinkly and had folds of skin from head to toe.

Once Australian farmers crossed these Vermont Merinos with their plainer-bodied Merinos, the heritability of the ‘wrinkled’ trait became apparent. Some producers liked the wrinkled skins as they believed it increased the yields of wool from each sheep, while others recognised the problems caused by the excessive wrinkly skin. The excessive wrinkles not only made shearing more difficult but made the sheep highly susceptible to flystrike.

Soon after the turn of the century, in the early 1900s, wool producers turned again to breeding plain-bodied Merinos as the issues caused by the wrinkles became apparent. In response to the increasing severity and occurrence of flystrike among Merino sheep, the operation of mulesing was developed by John Mules in 1931. From that point, it was used as a routine husbandry practice to overcome the problem.

Further information about the susceptibility of sheep to flystrike can be found at Flyboss – Breech strike.

While mulesing proved to reduce the incidence of breech strike, it became increasingly controversial and was deemed an unnecessary and cruel practice by many. Supporters of mulesing believed that the pain suffered by the lambs at mulesing was inconsequential compared to the lifetime benefits it provided. Due to the lack of an equally effective and practical alternative, many producers felt they were left with limited alternative options to avoid breech strike. In 2004, the Australian wool industry announced a plan to phase out the practice of mulesing by 31 December 2010; however, this target was abandoned in 2009.

Since that time, a practical and economic form of pain relief has become available. Tri-Solfen® is a gel that is sprayed onto the wound immediately after mulesing. It contains two local anaesthetics: lignocaine that is fast-acting to provide immediate pain relief and bupivacaine that is long-acting to provide more prolonged pain relief. Tri-Solfen® also contains adrenaline to help reduce blood loss and the antiseptic, Cetrimide. It is estimated that the majority of producers that mules their sheep now use Tri-Solfen®.

What strategies can producers use to control flystrike?

By using integrated pest management, producers apply a range of management strategies that aim to make the environment less suitable for flies to breed in their flocks. The choice of strategy and the timing of its application are influenced by the climate and weather patterns for the location. These management strategies include:

Additional resources

Managing flystrike in sheep (Department of Primary Industries and Regional Development, Western Australia)

What does the legislation say about mulesing?

There are several pieces of legislation that apply within NSW and prescribe what producers and schools can do in relation to mulesing. These include:

The POCTAA prescribes the legal age that sheep may be mulesed, stating that sheep must be under 12 months of age. This law applies to all citizens in NSW, including farmers, contractors, and teachers.

The Australian Animal Welfare Standards and Guidelines for Sheep are more prescriptive, stating that sheep must be a minimum of 24 hours old and no more than 12 months of age. If the sheep are between 6 months and 12 months of age, then pain relief must be used. This document includes further standards and 20 guidelines related to mulesing, which can be viewed from page 22 using the link above. This document applies to everyone in Australia.

The Animals in Schools website encourages schools to use plain-bodied Merinos that do not require mulesing. If the situation arises that schools have Merinos that require mulesing, then it must be carried out in accordance with the Australian Animal Welfare Standards and Guidelines for Sheep.

Additional resources

Pain relief for mulesing of sheep (Agriculture Victoria)

The future of mulesing

Mulesing is a controversial practice which has been increasingly considered as a practice that inflicts unnecessary pain on sheep. Despite this, mulesing has continued to be carried out around Australia. Many producers claim that it is an operation that only needs to be carried out once in an animal’s life, resulting in the prevention of breech strike for the whole of the animal’s life. It is a cost that is incurred once, both in terms of the financial cost to the producer, as it must be carried out by an accredited contractor, and in terms of pain to the animal that is mulesed. With pain relief now available, the process is less painful and considered more humane for the lambs.

While mulesing does significantly reduce the risk of breech strike, the genetic selection of less wrinkled sheep has also been shown to bring a dramatic reduction in flystrike. Unfortunately, it has been shown that reducing wrinkles in ultrafine and superfine Merinos can result in an increase in the fibre diameter of the wool. This has influenced the amount of selection pressure for reducing wrinkles that some producers are prepared to maintain in their ultra and superfine Merino flocks.

But over recent years many producers have taken the management decision to cease mulesing and find alternate ways to manage the problem of breech strike. In 2019, 11.4% of total wool production in Australia was classified as coming from Merinos that were not mulesed.

One of the largest influences driving the reduction in mulesing has been the worldwide retail and fashion sector, with a number of the world’s largest fashion retailers taking a stand against using wool from mulesed sheep and encouraging the use of wool from non-mulesed sheep, genetically selected flystrike-resistant sheep and sheep that have been given pain relief when being mulesed. As society becomes more aware of animal welfare issues, increasing pressure is being placed on wool producers and many are acknowledging the need to make changes to ensure the longevity of the Australian wool industry.

There are many fine wool Merino breeders who do not rely on mulesing for the control of breech strike. These are excellent practitioners at using a variety of techniques to manage the fly problem. Their strategies include additional crutching, use of chemicals, closer supervision of their animals and controlling dags, worm control, and pasture management. These strategies can help control flystrike to other parts of the body, in contrast to the use of mulesing that only controls breech strike.

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