The outline of the operation is extremely precisely described in the Code of Practice for the Welfare of Animals, The Sheep offered by the Commonwealth of Australia and each of its States and Territories in 2006. The appendix 3 describing it consists in a fifth of the publication summarizing all the practices that should be used in sheep breeding.
It is specified in this code that ”Mulesing will be carried out only in circumstances in which it is clearly in the best interests of the long-term welfare of the animals.” All the other options for breech strike prevention should have been considered before undertaking mulesing.
Moreover, “a comprehensive and audited training and accreditation process is available and mandatory for anyone who performs the mulesing procedure”. The pain associated with the procedure should be minimized through a topical analgesic applied immediately following the surgical procedure. Anesthesia during mulesing is not required.
The procedure should be performed in lambs between 2 to 12 weeks of age, in conjunction with the marking, when fly activity is expected to be minimal. It must be carried out in clean paddocks that could provide sufficient feed and water for at least 4 weeks after mulesing, thus avoiding the need to move the recovering lambs.
During the procedure, the lamb is restrained in a mulesing cradle. This provides a symmetrical horizontal position. Cleanliness and security of the lamb and of the worker are key points in the procedure.
The operation itself consist in removing the wool-bearing skin, excluding any underlying tissue, as shown on the following schema in the minimum of cut possible, the number of cut depending on the conformation of the sheep.
Diagram of the areas of skin that may be removed during mulesing (reproduced from Fisher, 2011)
After the operation, an approved insecticide can be applied using a spray before releasing the lamb from the cradle to prevent any flystrike during the healing of the wound. The lamb is then released on its feet to prevent any contact between the wound and the ground that could lead to contamination.
After the procedure, the lamb is given back to the ewe and the movements of ewes and just-mulesed lamb should be limited for four weeks. A monitoring of the animals should be perform at least every three days during the healing process, the frequency increasing where the threat of flystrike or other risks are likely.