The end of the shear may be near. As serendipity would have it, scientists at Australia’s Commonwealth Scientific and Industrial Research Organization discovered 10 years ago that a natural animal protein, called epidermal growth factor (EGF), makes fleece fall off sheep like butter off a hot knife. Now scientists have finally isolated the gene that makes EGF and have built what amounts to protein factories. Scientists splice EGF into bacterial genes and then grow them in large fermentation vats-similar to those used for making soy sauce. Once inside, the bacteria reproduce themselves–creating a potful of EGF which can be readily isolated.
EGF works by weakening hair follicles. Ranchers give a single injection when the fleece is ready to harvest. Then the sheep are wrapped in snug polypropylene coats to keep them warm and protected from sunburn; in the fields they look like four-legged dowagers snuggled into down overcoats. Within a week the follicles have loosed their grip on the old wool; new wool starts to grow, pushing out the old strands. When the plastic coat comes off six weeks after the injection, the fleece falls off in a single, unmutilated sheet.
Don’t look for EGF at a pet store near you quite yet, however. Pitman-Moore, the subsidiary of the American health-care-products and chemicals firm Imcera that holds the marketing rights to EGF, hopes to win regulatory approval for the hormone sometime in 1992. Safety issues don’t seem to be a problem: injected sheep could still be eaten, since there are no EGF residues and the animals “get a very small dose of what is, after all, a natural hormone,” says Pitman research vice president Thomas MacRury. The only warning sign: pregnant ewes given EGF tend to abort. Unless that portends more general health effects, the only hurdle is price. Can a dose of EGF come in below the $2.75 it costs to shear a ewe? But EGF may find a wider market: it works on any mammal. Olympic swimmers and Persian-cat owners, take note.
Photos:
A shear delight: After a growth-protein injection, sheep are zipped into coats to protect their hides while new wool grows. Six weeks later, farmers have a fuzzy animal and perfect wool
