MERINO ewes that scored favourably for breech cover and wrinkle could shift progeny to bare breech in one cross.

That is if they are joined to bare-breech sires, according to wool grower and stud breeder Phil Toland.

Mr Toland, from Violet Town, is chairman of the North East Victorian central test sire evaluation.

Run since 1997, the trial incorporated a bare-breech component last year.

Four polled and horned Merino sires, with a reputation for wrinkle reduction or bare breech, were used in the trial.

They were Calcookera Jim 02 0027, North Ashrose 05 0025, Cranmore 07 3234 and Toland Poll 07 1139.

Mr Toland said preliminary data showed there was potential to significantly reduce wrinkle in one cross.

"The whole aim of this trial is to find a viable genetic solution to mulesing," he said.

"We think that genetic solution is achievable."

Run at the University of Melbourne's Dookie campus in Victoria's North East, the trial involved artificially inseminating 50 Merino ewes to each sire.

It is part of a wider trial studying fibre diameter, fleece weight, wool quality traits, growth and structural soundness.

Last month, at five months of age, the 2009-drop weaner lambs were scored for breech cover and wrinkle.

They were then displayed to the public by the North East Merino breeders group.

For breech cover, they were scored on the natural bare area around the breech from one (large) to five (no bare).

The degree of breech wrinkle at the tail set and hind legs was scored from one (nil) to five (extensive).

For breech cover, 32 per cent of lambs sired by Calcookera Jim were scores one and two, followed by 31 per cent of Toland Poll 07 lambs.

Cranmore led the way for breech wrinkle with 33 per cent of lambs at scores one and two.

Mr Toland said the progeny was scored at two weeks of age at tagging and early post weaning at five months.

"We found scoring young lambs on breech cover is not reliable and they need to be six months of age," he said.

Mr Toland said it was important not to join Merino ewes with breech wrinkle scores of four and five to Merino rams.

"Join these ewes to terminal sires only," he said.

"It is best to concentrate on wrinkle reduction followed by bare skin."