Wagyu breeders move to single-step BreedPlan evaluation


Australian Wagyu cattle producers are now armed with genomic-based data enabling more robust selection decisions with faster gains and higher accuracy through a shift to a new own-breed genetic analysis model.

The Australian Wagyu Association has confirmed that Single Step Wagyu BreedPlan will be published from tomorrow (Tuesday), utilising refined analysis and software improvements drawing solely on Wagyu performance data to deliver the world’s first public Wagyu-specific genomic and pedigree analysis platform.

Matt McDonagh

“Single Step Estimated Breeding Values mean Australian and International Wagyu are now being benchmarked against the best of their own breed under more stringent assessment criteria and weightings,” AWA chief executive Dr Matt McDonagh said.

In developing the Single Step EBVs, the AWA has worked collaboratively with staff at the Animal Genetics & Breeding Unit and the Agricultural Business Research Institute, with funding support from Meat & Livestock Australia, to implement a new approach for incorporating genomic (50K SNP) information into a Wagyu-specific EBV calculation.

Significant improvements in EBVs that more closely reflect genetic relationships in Wagyu data will be evident, the association said.

As an example, Mr McDonagh said that for ‘high accuracy’ sires with a previous EBV accuracy of more than 75pc, the EBV for Marbling Score had decreased in range by approximately 1 EBV Marble Score unit. The previous top Marbling Score sire had an MS EBV value of + 3.4.  That figure is now + 2.6, but the same sire remains the industry leader for marbling score.

“The decrease in value range for marbling score is primarily due to the addition of genomic analysis within Single Step Wagyu BreedPlan, which has detected a higher degree of relatedness between popular sires than was previously estimated by pedigree within standard Wagyu BreedPlan,” Dr McDonagh said.

The impact of the reduced  range of Marbling Score EBV is a $269 reduction in the range in the related Terminal Carcase Index for high accuracy sires. The sire with the previous top Terminal Index value of $792 remains the top ranking sire, with a new Index value of $587.  The sire with the previous lowest Index value of -$338 is now -$274 in the Terminal Carcase Index.

The Terminal Carcase Index has been well-adopted by industry, but is not intended for use in breeding replacement livestock.  With implementation of Single Step Wagyu BreedPlan, the AWA said it would now introduce a parallel Fullblood self-replacing herd index in coming months.  This will assist in selection for breeding stock and accelerate breed development in a variety of related traits.

For high-accuracy sires, the range in EBV for Carcase Weight has increased in range by 35kg. Previously, the highest Carcase Weight EBV among this group of sires was + 58.1 kg: the highest CWT EBV in this group of sires is now 75.0 kg.

This increase in EBV range is largely due to the improved estimate of the heritability of Carcase Weight enabled by the substantially expanded Wagyu-only dataset. The genetic contribution to Carcase Weight is now recognized as significantly higher than previously estimated.

These changes mean that within Single Step Wagyu BreedPlan, the Carcase Weight EBV now has a relatively larger influence on Terminal Carcase Index, with the Marble Score EBV having a lesser influence.

These changes have been applied to the April 2018 Wagyu Group BreedPlan analysis and will now apply to subsequent monthly analyses.  The new Single Step Wagyu BreedPlan model is now based solely on Wagyu data and Wagyu EBVs are directly derived from Wagyu performance data.

This means that Single Step Wagyu BreedPlan is a world-first Wagyu specific genomic and pedigree analysis platform, the AWA said.




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