LIMOUSIN cattle breeders reckon they're on to a winner with the F94L muscling gene.

The gene, a variant of the myostatin gene common in heavy-muscling breeds such as Belgian Blue or the Blonde d'Aquitane, was discovered by a research team from the University of Adelaide, led by Dr Wayne Pritchard.

The discovery was part of the Beef Co-operative Research Centre's research into mapping the genes associated with meat tenderness, muscling and eating quality.

What was significant about the discovery was that the F94L gene, which could boost muscling and meat yields by 20 per cent, was highly prevalent in the Limousin, particularly those bred from pure French bloodlines.

Following the F94L discovery, a DNA test can now determine the presence of the gene and whether a calf carries one or two copies of it.

A single copy can boost muscling by 4 per cent, whereas two copies can boost muscling and yields by 20 per cent.

"It's pretty exciting really, because you're getting about 20 per cent more of the really high-value cuts," Dr Pritchard said.

"You get more loin muscle, which is the one that runs down the back and is the highest-quality cut."

Dr Pritchard said the gene also increased tenderness.

"Meat from animals with the gene can require up to 15 per cent less force to cut it," he said.

"The eating quality, however, is expected to remain the same as meat without the gene.

"The downside is that the gene does reduce the amount of fat in the meat; both the fat cover on the animal and the intramuscular fat."

Dr Pritchard said surveys showed the increased tenderness and decreased fat balanced out, to give meat of normal eating quality.

"The increase in tenderness has been attributed to a decrease in collagen," he said.

"The muscle fibre of the meat remains the same, but there is a reduction in connective tissue."

Dr Pritchard said the good news was that animals with the gene did not require any additional feed.

"You are basically getting more meat for the same cost of production," he said.

A year ago several Limousin breeders identified a marketing opportunity in the gene and established the Limousin Muscle Alliance to promote the trait.

Tim Keys, who is a foundation member of the alliance and principal of Keystone Genetics, at Springhurst, said the alliance already had 60 members, who were committed to breeding and marketing Limousins with two copies of the gene.

On February 26, 14 alliance members (five Victorian, four each from NSW and Queensland and one West Australian) will participate in the inaugural Limousin Muscle Alliance sale, conducted on the remote bidding facility AuctionsPlus.

The alliance has catalogued 53 cows and heifers, two embryo packages, eight semen packages and 37 yearling to two-year-old bulls.

Mr Keys said all lots had either been DNA-tested for two copies of the muscling gene, or were of pure French bloodlines.

He said the cows and heifers would be attractive to other stud breeders, but the bulls would appeal to both stud and commercial breeders.

Mr Keys said a producer who crossed a Limousin bull that carried two copies of the gene with a first-cross Angus-Friesian vealer mother could expect the progeny to have a 10 per cent increase in muscling and yield.

He conceded that Limousin stud breeders fell into two camps - those promoting muscling and those breeding a more growthy animal with higher fat cover.

"But ultimately all Limousin breeders have to maintain muscling as a major trait," he said.