A groundbreaking anaesthetic for a painful animal husbandry practice has won the backing of a global pharmaceutical giant.

The anaesthetic, marketed under the name Tri-Solfen, was developed by Sydney paediatrician Meredith Shiel to relieve the pain of mulesing for lambs.

Mulesing, targeted by activists in a global animal rights campaign, involves cutting skin folds away from sheeps' backsides to prevent fly strike.

Multinational pharmaceutical company Bayer recently announced it had taken over the licensing and marketing of the treatment.

Dr Shiel, who also has a sheep farm in the NSW central tablelands, said she hoped the deal would take her invention around the world and eventually stop activists from targeting Australian wool.

"I think it's really important that consumers don't get the impression that wool is associated with cruelty," Dr Shiel said.

"By adopting pain relief, Australian wool farmers will actually be leading the world because so many procedures on all sorts of production animals are done without any pain relief whatsoever.

"We'll be the first group of producers who are taking on this welfare issue and doing something about it."

Trials have shown the anaesthetic promotes healing and improves mobility and feeding.

The US-based People for the Ethical Treatment of Animals is continuing its worldwide campaign against Australian wool in a bid to end mulesing well before the industry's commitment of phasing it out by 2010.

Tri-Solfen was granted a oneyear permit by the farm chemicals regulator, the Australian Pesticides and Veterinary Medicines Authority, last year, and is expected to win permanent registration in the next few months.

Available through veterinarians, it costs about 9/ml, with an average cost of 50/sheep.