Lamb traits tracked for quality

In a world-first, Australian researchers are releasing new genetic traits that have potential to impact on lamb lean meat yield, carcase characteristics and eating quality.

These new traits come from the Sheep CRC’s Information Nucleus program, Sheep Genetics and the collaborative Genomics Pilot Project.

CRC’s manager of Sheep Genetics Sam Gill said the new Research Breeding Values (RBVs) that had been developed represented two major advances in the application of genetic technologies to sheep breeding.

“Firstly, the prediction of the RBVs for these traits uses a combination of new genomics technology and conventional genetics, and potentially will enable ram breeders to fast track sire selection through reducing the need for progeny testing.

“Secondly, these new traits are ‘hard-to-measure’ as they can only really be assessed either from measurement at the processing level or through extensive consumer evaluation, which both involve costly sampling and testing.”

Above this, the traits will have a direct bearing on both farm productivity and consumer satisfaction.

In summary, the new traits are listed in the table, right.

Ultimately, breeders will be able to select for, and use, these traits in their ram selection and breeding programs to simultaneously increase flock and farm productivity (for example, through more kg lamb/ha) and ensure vital consumer lamb-quality attributes (for example, tenderness and taste) are retained or improved.

This relationship is essential to maintain a ‘balanced’ animal, as this research has confirmed farmer and butcher experience that selecting alone for just one trait may compromise another.

For instance, strongly selecting for LMY alone might compromise tenderness if correlations are not accounted for.

Sheep CRC chief executive James Rowe said this was an exciting advance for the Australian sheep industry and positioned it to use genomic technologies to improve and accelerate genetic gain.

“The genomics work has created much interest among both stud breeders and commercial producers of all sheep types — Merino, maternals and terminals,” Professor Rowe said.

“Essentially, DNA analysis of samples from young animals is used to provide a prediction of its breeding value.

“Though we need to appreciate that we are at the forefront of a new area — hence we’re referring to these as Research Breeding Values at this stage, which have accuracy levels somewhat lower than would normally be reported as ASBVs.

“However, their scope and accuracy will continue to improve as more data is collected from the Sheep CRC’s Information Nucleus flocks and other sources.

“We’ll continue to provide updates on the traits reported to date and on new research breeding values as the database grows and our analyst team generates more information.”

The ‘Research Breeding Values’ are the result of incorporating the genomic information into the existing phenotypic datasets in order to give breeders the most accurate descriptions possible.

As soon as they reach target accuracies, and have appropriate industry validation, the RBVs will move into Sheep Genetics LAMBPLAN and MERINOSELECT platforms.

In due course, the RBVs will move to routine ASBVs that have genomic predictions included.

A Phase II Genomics Pilot will be run in conjunction with industry in 2011-12 to refine logistical processes in the lead-up to commercialisation of DNA testing for the sheep industry — possibly in 2012 — and to road-test the use of genomic testing in sheep breeding programs in studs.

Information on the new RBV traits has been provided to ram breeders who have taken part in the Genomics Pilot Project and those who have provided industry reference sires in the Sheep CRC’s IN flock.