By Wilson da Silva
SYDNEY – One of Australia’s best-known images – the sun-tanned sheep shearer clipping fleece at breakneck speed – may soon become a piece of history. Australian scientists have invented a hormone that causes the fleece to peel off, saving the animal from a traumatic experience and cutting the price of wool by up to 25 per cent.
Commercial use of the hormone may be as little as two years away, which could be good news for Australia’s troubled wool industry and its 166 million sheep.
The genetically engineered hormone EGF, which a U.S.-owned drug company plans to market, weakens wool strands on the back of a sheep and makes the fleece peel off.
“Within about 10 days of injection, the animal is bare,” said Dr Oliver Mayo of the animal production division of the Commonwealth Scientific and Industrial Research Organisation (CSIRO).
“Sheep don’t like to be shorn, it’s very traumatic for them. This is a lot easier on the animal and you get this beautiful, evenly-cut creamy-white fleece,” he said.
EGF, meaning epidermal growth factor, is injected into sheep and over a five- to 10-day period weakens its wool follicles.
When wool resumes growing, the weak strand is pushed out and the fleece’s weight on the outside forces it to drop.
Pitman Moore Australia Ltd, a subsidiary of Imcera Group Inc of the United States, has bought the marketing rights to EGF and expects to introduce it to the market in the next two years.
The firm’s market development manager, Ron Hailing, said that EGF was in the development phase and looked very promising.
“We’re looking at ways of producing EGF in commercial quantities, which requires genetic engineering techniques, and we’ve done that,” he said.
But several obstacles must be overcome first. The firm must develop a whole new way of harvesting wool and managing sheep.
Unlike shearing, which cuts off only the top layers of the coat, EGF sheds all of the fleece, right down to the roots.
While this produces a continuous and higher quality coat, it also leaves the sheep naked and prone to injury and sunburn.
Sheep must therefore be wrapped in a “hairnet” jacket for six weeks, allowing new wool strands to grow long enough so that they push through skin layers, break the surface and grow long enough to provide skin protection.
Because the breaks occur at different times in different parts of the body, the jacket must be put on immediately after injection. After six weeks, it is removed and the wool can be peeled off as one continuous fleece.
Scientists say EGF will work for farmers like a dream, and spell an end to the back-breaking work of sheep shearing, which increasingly relies on imported labour.
Shearing accounts for about 25 per cent of the cost of wool production, amounting to 260 million dollars (203 million U.S.) a year in Australia, the world’s biggest wool supplier.
It costs about 3.50 dollars (2.74 U.S.) to shear a single animal, including labour and equipment.
Rams, heavier and more aggressive, cost double this to clip, since shearers must not only deal wih a more cumbersome animal but take care when cutting around his large sex organs.
The price of the EGF process, including the polypropylene jacket, must therefore be brought down to around 3.50 dollars per animal to make the process viable.
“We believe we can get the price (for the jacket) down to a satisfactory level and make the process commercially viable,” said Pitman Moore researcher Doug Pollock.
Researchers and the company are optimistic. A spokesman for the government’s Wool Research and Development Corp said the process was likely to be applied first to the more troublesome and expensive rams before spreading it across the industry.
Pitman Moore is working to lower production costs of EGF and reduce time and labour involved in putting the jackets on the animals and taking them off again.
The company must first develop lightweight and comfortable jackets that cannot be damaged by the sheep in the paddock, can be re-used several times and are cheap to produce.
It hopes eventually to see the jackets in use on the world’s 1.17 billion sheep.
“The resulting fleece is very good,” said Dr Terry Leche of the CSIRO. “There are no second cuts required for the spots that were missed and it leaves the animal with a nice, smooth and very comfortable short coat. The process is quite trouble-free.”
But there are problems. When injected with the hormone, most pregnant ewes suffer abortions and both males and females lose their appetite for a day.
The researchers have found that there is a window of around 90 to 110 days after pregnancy during which most ewes can be injected without inducing abortions.
But Mayo said it would be preferable if pregnant sheep were not injected at all, something that would require a change in current wool harvesting practices.
The hormone stays less than 24 hours in the sheep’s body, causes no long-term damage, and authorities have approved sheep injected with it as fit for eating, even if slaughtered shortly after injection.