What is sheep freeze branding (or steining) and is it an acceptable alternative to mulesing sheep?

Sheep, especially Merinos, have woolly wrinkles and folds around the tail and breech area which attract blowflies and may become infested with maggots (flystrike). Sheep farmers have traditionally used mulesing to reduce flystrike risk. Alternatives to mulesing have been trialled over the years; the most recent is ‘sheep freeze branding’, previously referred to as ‘steining’.

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 scar tissue. 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 ‘sheep freeze branding’?

Sheep freeze branding involves the application of liquid nitrogen directly to a lamb’s skin around the tail and breech area. This causes the skin to die and drop off to leave an area of stretched, scar tissue similar to the effect of mulesing.

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 [1]. There is no scientific evidence to suggest that the current application technology causes any less pain or distress to sheep. A more recent report found similar pain-related behaviours between lambs subjected to sheep freeze branding or mulesing when both procedures were accompanied by pain relief [2]. Irrespective of adaptations of the method itself, the application of liquid nitrogen directly to the skin, will cause pain to the lamb.

What is 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 RSPCA believes that it is unacceptable to continue to breed sheep that are susceptible to flystrike and therefore require an ongoing need for mulesing or other painful procedure to manage flystrike risk.

The RSPCA believes that humane, alternative practices that preclude the need for mulesing should be adopted. Any painful procedure to change the breech area 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.