Tenderness is all in the genes

Haidee VandenbergheCountryman

Australia's national dish could be set to become even more mouth-watering after groundbreaking research located the gene responsible for tender and tasty lamb.

As part of a multi-million dollar project looking at the genetic factors involved in a whole host of sheep traits, scientists have been able to crack the DNA code for eating quality.

The breakthrough was made by scientists working on a jointly funded Sheep CRC and Meat and Livestock Australia (MLA) project and revolutionises the way the meat industry thinks about lamb's eating characteristics.

WA-based scientist and Sheep CRC Meat Program leader Dave Pethick said the research proved tasty lamb wasn't just about the right handling and killing.

"A lot of supply chains think providing you kill the lambs correctly... and then you have perfect abattoir conditions and age the meat - that's all you need to do," he said. "These are very important things to do... (but) this is a whole new area in variants in eating quality that as yet has been untapped and its importance is just as high as the abattoir end."

Research centred on the calpain/calpstatin genes, which controls the natural tenderisation of meat in sheep and other livestock species.

A natural variation in this gene group was found in 35 sires from the Sheep CRC's Information Nucleus Flock - which each year sees 100 young industry sires mated to 5000 ewes.

Two thousand lambs are slaughtered, with their carcase muscling, fatness, bone and weight measured.

But importantly, scientists have also been measuring some eating quality parameters such as intramuscular fat and sheer force - or mechanical tenderness.

Each lamb had a full 50,000 gene set completed to look at how gene markers associate with intramuscular fat and sheer force.

"We've already shown that these are very significantly genetically inherited," Dr Pethick said.

"In fact, using traditional genetics through Lambplan and Merino Select we've got research breeding values for the commercial colleagues who have put rams into the system."

The push has long been on to breed bigger and more efficient sheep, but increased muscle and leanness has sometimes been at the expense of eating quality. But not anymore.

"If you only selected for the carcase you would slowly decline eating quality but there are plenty of sires who have good carcase attributes and good eating quality," Dr Pethick said.

"(However) you've got to find them and the only way to find them is to make sure you measure both.

"(You can) scan for muscle, fatness and carcase weight and they've been very effective, but we've had no tools to do eating quality.

"So now you've got tools to do both the carcase characteristics for your efficiency parameters and at the same time you can also measure eating quality."

It could pave the way to niche marketing of a premium, guaranteed good eating product and that's something which has got growers excited.

Narrogin stud breeder Dawson Bradford starting breeding Poll Dorsets 52 years ago and said the breakthrough was the most significant he had seen in his career.

"Lamb with that sort of (eating quality) guarantee would have a niche market straight away," he said.

"I see it as an opportunity for producers to produce a premium product and expect a premium price."

A dozen of Mr Bradford's rams were profiled as part of the Sheep CRC research, with a number proving they had the tender meat gene variation. The passionate livestock producer sells 350 to 400 rams a year and said although they already did objective measuring for muscling and growth rates, genetic evidence of eating quality was the last piece in the puzzle.

"The heartening thing is once you can identify those genes you can spread them through the flock," Mr Bradford said.

Yealering Border Leicester ram producer Kelly Manton-Pearce had three rams DNA sequenced and agreed the findings would impact on the way producers bred meat sheep into the future.

"I believe all terminal sire breeders should closely follow these findings as they continue to concentrate their breeding programs to focus on muscling," she said.

"As a maternal breeder we have an advantage because maintaining fatness and balancing with muscling is an important breeding objective to ensure reproductive ability, thus minimising reductions in intramuscular fat.

"I believe these findings will help us breed not just better first-cross mothers but also produce the premier meat from their brothers and their second-cross lambs that's of high eating quality and has high lean meat yield."

The project has already developed research breeding values for intramuscular fat and sheer force and the next step is to develop a consumer breeding value to estimate the eating quality of meat from the topside and loin.

"We always planned to get 10,000 lamb records in the bank, we've got 8000 at the moment so we've got one more cycle to go," Dr Pethick said.

"When we've got 10,000 records with all the end quality, lean meat yields and all genotypes with the 50,000 gene SNP chip then we'll be able to release fully commercial breeding values to the industry."

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