Sheep, especially Merinos, have woolly wrinkles and folds around the tail and breech area which attract blowflies and may become infested with maggots. This is called flystrike (or flyblown), and if left untreated, is fatal. Mulesing, a painful procedure where sharp shears are used to cut away the wrinkly skinfolds, is traditionally performed on lambs to reduce flystrike risk. Alternatives to mulesing have been trialled over the years; the latest is ‘steining’ or ‘sheep freeze branding’.
What is mulesing?
Mulesing is a painful procedure that involves cutting crescent-shaped flaps of skin from around a lamb’s breech and tail using sharp shears. The resulting wound, when healed, creates an area of bare, stretched skin. Because the scarred skin has no folds or wrinkles to hold moisture and faeces, it is less likely to attract blowflies. This makes mulesed sheep less susceptible to flystrike in the breech area.
What is ’steining’ or ‘sheep freeze branding’?
Certain compounds can be applied directly to the skin of the lamb causing it to die and drop off to leave an area of stretched, bare skin similar to mulesing.
Steining (also referred to as sheep freeze branding) involves the application of liquid nitrogen to the lamb’s skin. The procedure uses a device that tightly clamps excess skin on the lamb’s breech and then applies liquid nitrogen to this clamped skin until it is fully frozen. The clamp is then removed and treated skin eventually falls off. Studies of an earlier model of the applicator found that the method is painful and had no benefits in terms of reduced pain over mulesing regardless of whether pain relief was provided . There is no scientific evidence to suggest that the current application technology causes any less pain or distress to sheep. Irrespective of adaptations of the method itself, the application of liquid nitrogen directly to the skin, will cause pain to the lamb.
How does ‘steining’ or ‘sheep freeze branding’ fit within the National Wool Declaration?
The National Wool Declaration (NWD) allows wool growers to voluntarily communicate the mulesing status of their sheep to wool buyers at auction. Wool growers are asked to declare, on a mob basis, whether wool from that mob is from sheep that have not been mulesed (NM), whether some or all sheep have been mulesed (M), or whether all sheep were mulesed using pain relief (PR). If sheep are no longer mulesed on the property (and haven’t been for the last 12 months), then the grower declares ‘ceased mulesing’ (CM). Each of these categories attracts a premium per kilogram of wool sold at auction.
The NWD definition of mulesing limits the procedure to the use of shears. This effectively means that the ‘NM’ category on the NWD applies where other breech modification methods (including steining or sheep freeze branding) would be categorised as ‘NM’. It is important that wool buyers who are seeking to source wool with good animal welfare credentials are able to easily identify that product. This means introducing an additional status category, e.g. ‘other breech modification’, to the NWD. The wool industry should be transparent about their current practices and wool buyers should be able to make fully informed choices. As such, it would be important for the NWD to include information about the specific breech modification that has occurred.
The RSPCA’s position
The wool industry has sought to develop viable and humane alternatives to mulesing. To date, none of these alternative solutions has had wide industry uptake and/or been proven to be commercially viable. The adoption of other breech modification methods as an alternative to mulesing does not address the underlying need which is to breed plainer-bodied sheep (i.e. less wrinkles) which is one of the most important strategies to reduce flystrike.
The RSPCA believes that humane, alternative practices that preclude the need for mulesing or breech modification should be adopted. Any breech modification procedure should only be considered an interim, short-term solution that accompanies a breeding program that focusses on flystrike resistance, and is carried out only where absolutely necessary to manage at-risk sheep.
It is unacceptable to continue to breed sheep that are susceptible to flystrike and therefore require an on-going need for breech modification (including steining or sheep freeze branding, or mulesing) to manage flystrike risk.
 Small A, Lee C (2018a) Welfare assessments of analgesic options in female lambs for surgical mulesing and its alternatives. AWI Project Summary Report ON-00026 29 May 2018. Australian Wool Innovation Limited, The Rocks, Australia.