1990 - Volume #14, Issue #2, Page #05[ Sample Stories From This Issue | List of All Stories In This Issue | Print this story | Read this issue]
Shearing Sheep Without Shears
Biological wool harvesting involves the intramuscular injection of an epidermal growth factor (EDF) which occurs naturally in sheep. The extra dosage of EGF causes weakening of subcutaneous hair follicles. When the weakened follicles are pushed through the skin by natural hair growth, they break, causing the fleece to fall off.
It takes about two weeks from the time of injection for the fleece to be stripped from the animal, and then another four weeks to allow a new subfleece to grow.
A plastic fishnet coat has been developed to retain the wool on the sheep until they're corraled for wool harvesting. The coat, put on when the animal is injected, not only holds the fleece against the animal to keep it warm, but also protects against burrs and seeds.
When the coat is removed, the fleece simply falls off, leaving a new coat about 1/3 in. long which has been growing beneath the old fleece.
Researchers believe use of the coat is essential to allow the new covering of wool to grow before the animal is exposed. Without the coat, the fleece would drop off, leaving the animal without any wool and obvious problems with exposure.
To harvest the wool, researchers have developed a conveyor belt system. Sheep are placed on the belt on their backs and shunted past "shearers" who first pluck wool from the animal's belly, then turn it over and strip the fleece off the back. The entire process takes less than one minute and the fleece stays together in the same way as a shorn fleece.
At this stage, the cost of the EGF dosage, a key determining factor in commercial applications, isn't known.
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