A marble-ous genetic advantage

12 Dec, 2014 01:00 AM
No other beef breed has the same trait to the same degree, or so much money riding on it

IN THE same way the Australian wine industry de-mythologised French winemaking traditions and cut its own path into a sheltered market, the Australian Wagyu sector is fast building an objective case for its genetics.

For Wagyu, the money lies in carcase characteristics, especially high marbling under long feeding regimes. No other beef breed has the same trait to the same degree, or so much money riding on it.

Wagyu breeding decisions around marbling often still rest on the reputations built around historic Wagyu lines - Tajima, Fujiyoshi - developed in Japanese prefectures.

But two years ago, the Australian Wagyu Association (AWA) decided to put some local science behind the prefectural myths, and develop Wagyu-specific estimated breeding values (EBVs) for profit-driving carcase traits.

If that wasn’t ambitious enough, AWA also decided to draw on new genomics technology to accelerate development of those new EBVs, and to roll the technologies together in a quest to identify new, valuable bulls.

Development from scratch of an EBV for a slow-developing breed like Wagyu could take four to five years - the time it takes for a bull to get progeny on the ground, for the progeny to mature, go through 400-600 days on feed, be slaughtered, and the data related back to the sire.

But two years after the project was conceived, in October 2014 Animal Genetics and Breeding Unit (AGBU) director Rob Banks told the national Wagyu Conference that research EBVs with enough robustness to be useful were now available.

The researchers commissioned by AWA and co-funder Meat and Livestock Australia achieved this feat by working backwards.

Instead of tracking bull performance forward, they combined new carcase assessment technology with DNA pedigree techniques to find animals responsible for the best carcases.

More than 3000 Wagyu carcases were analysed by a special camera, developed in Japan, that can assess marbling percentages well beyond the capability of the human eye.

Tests found that the camera and the AUS-MEAT language for describing marbling are strongly in agreement in lesser marbled cuts, but as intramuscular fat moves towards Marble Score 9 the camera can detect variation that confuses the eye.

A cut that grades into MS9 may contain as little as 18 per cent marbling, and as much as 50pc. The human eye often doesn’t see the difference, but the camera almost always does. And the camera also found that 17pc of Wagyu carcases grade above MS9, on up to MS12.

Still, there is enough agreement between the camera and AUS-MEAT data for AWA to decide that historic AUS-MEAT data on Wagyu carcases can be used to strengthen the new carcase EBVs.

Not only quality was assessed in the meat cuts. For about 2000 samples, DNA material was used to correlate the pedigree of the animal.

“We looked at whether the genotypes we had on those slaughter cattle could help us confirm or improve the pedigree information we already had,” Dr Banks said. “And if we didn’t have any pedigree information, could we use genotype alone to determine it? The answer in all cases was yes.”

This was largely made possible because of the unique qualities of the Wagyu supply chain. Large cohorts of animals, managed as a unit throughout their lives, deliver a clear genetic signal from the data. Try to do the same on a batch of animals out of a saleyard with mixed origins, Dr Banks observed, and there might be so much noise that the signal isn’t discernable.

As it was accumulated and verified, genomic data was fed back into the Breedplan database to improve the robustness of existing performance data.

The result of this work so far is Wagyu-specific research EBVs for Fineness of Marbling, Marbling Percentage and Rib Eye Area (all generated from camera imaging), and Carcase Weight and Marbling Score EBVs generated from AUS-MEAT and Meat Standards Australia data.

AWA has released rankings of the over 100 leading sires for each breeding value, available on www.wagyu.org.au.

Although they are currently tagged “research EBVs”, Dr Banks thinks there is already enough robustness in them to produce value for breeders.

The Association is now on a campaign to obtain a consistent flow of new data from breeders and processors, to bolster the reliability of its new EBVs.

If Wagyu breeders can collectively supply 1000 or so records a year, the breed may be also close to having capability now only available to the dairy industry: using DNA to interrogate Breedplan for the performance potential of very young animals, to identify them long before they have delivered their first progeny.

For Wagyu, this might also extend to screening animals for feedlot performance.

“This is the first time this information has been available anywhere, at least outside Japan - and we can’t get access to Japanese information,” said AWA chief executive Graham Trustcott, a key driver of the initiative.

“This is setting up the Australian industry for a unique early-entrant advantage to the global Wagyu market.”



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