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Updated Eye Muscle Area WBV

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Updated Eye Muscle Area WBV

Development of the Eye Muscle Area WBV

The Eye Muscle Area WBV was developed using a revised genetic evaluation framework that reflects modern Wagyu data and production systems.  The Eye Muscle Area EBV and WBV are derived from the same phenotypic records and are expressed in the same units, but differ as a result of updated genetic parameters and higher volumes of data.

 

Wagyu-Specific Genetic Parameters

EMA WBVs are calculated using:

  • Heritabilities estimated solely from an increased Wagyu dataset
  • Updated Wagyu-specific genetic correlations
  • Full multi-trait models incorporating growth, carcase weight, and marbling traits

This allows EMA to be evaluated in a more correct biological context for Wagyu.

 

Comparison: EMA EBVs vs EMA WBVs

Figure 1. Eye Muscle Area EBV vs Eye Muscle Area WBV (All Animals)

Description:
The following scatter plot of EMA EBVs (x-axis) against EMA WBVs (y-axis) shown the relationship between EMA EBVs and WBVs across the whole Wagyu population.

A significant change in the statistical model used to calculate Eye Muscle Area WBVs results in significant change in the genetic estimate for this trait in some animals.  In general, the WBVs for Eye Muscle Area are positively correlated with EBVs, with high EBV animals tending to be high WBV animals.  However, the correlation is only 0.73, meaning that there is significant re-ranking due to the updated Wagyu-specific parameters used in calculating WBVs.

EMA WBV

Figure 1. Distribution and Correlation of Eye Muslce Area EBVs (x axis) and Eye Muscle Area WBVs (y axis) for all animals.

 

Interpretation:

  • Animals with high EMA EBVs generally remain high for EMA WBVs
  • The moderate correlation indicates meaningful re-ranking for some animals
  • Re-ranking is driven by corrected trait relationships rather than data noise

 

Improved Genetic Relationships Under WBVs

Under the new WBV model, Eye Muscle Area shows:

Trait Category Genetic Relationship
Growth traits Positive
Carcase weight Positive
Marbling score Positive

 

These relationships better reflect relationships between traits within the AWA database.

What This Means for Breeders

What Remains the Same

  • EMA remains a comparative genetic measure of Eye Muscle Area
  • Higher values indicate genetically larger eye muscle area
  • Accuracy should guide confidence in selection decisions

What Improves

  • Better alignment with observed progeny outcomes
  • Reduced bias against growth-oriented animals
  • Improved ability to select eye muscle area and growth
  • More biologically realistic rankings across the population

 

Why This Change Is Only Possible Now

The transition from EMA EBV to EMA WBV is enabled by:

  • A large increase in Wagyu-specific EMA records
  • The ability to re-estimate parameters using Wagyu-only data
  • Independent AWA genetic evaluation capability

 

Conclusion

The replacement of the Eye Muscle Area EBV with the Eye Muscle Area WBV represents a substantial technical improvement in how eye muscle area is evaluated in Wagyu cattle. By correcting trait relationships and embedding EMA within a Wagyu-specific multi-trait framework, WBVs deliver a more accurate and biologically meaningful assessment of carcase muscling.

IMPORTANT NOTICE - Terms & Conditions

It is a condition of use of this database that you accept these terms and conditions. 

It is important that you appreciate when accessing the Australian Wagyu Association Limited (AWA) database (which may be hosted on an external website) that the information contained on the AWA database, including but not limited to pedigree, DNA information, Wagyu Breeding Values (WBVs) and Index values (together called Database Information), is based on data supplied by AWA members and/or third parties.  

Whilst sincere effort is made to ensure the Database Information is accurate and complete, to the extent permitted by law, AWA, its officers and employees, shall not be responsible for its use or interpretation, and you use the Database Information at your own risk. Please be aware of the following limitations of the Database Information.  

Regarding WBVs and Index values, it is important to appreciate, and you need to be aware that:  

  • WBVs are derived using genetic evaluation technology developed for the AWA, using the information contained within the AWA database.  
  • WBVs are estimates of genetic potential of individual animals and may not reflect the raw animal phenotype.  
  • WBVs can only be directly compared to other WBVs calculated in the same AWA genetic analysis.  

Regarding pedigree and DNA testing results submitted to the AWA, it is important to appreciate, and you need to be aware that:  

  • Animals whose registration identifiers start with PED are Pedigree Recorded Animals. What this means is that the details which AWA used to register the animal were obtained from a Recognised Wagyu Registry Organisation – in other words a Wagyu breed association based outside of Australia. AWA has not independently verified the information with respect to the animal or the details recorded about the animal. You should read AWA’s by-laws which set out details regarding the definition of a Pedigree Recorded Animal.  
  • Pedigree and DNA data submitted and supplied to AWA may have errors in it which cannot be detected without further DNA testing.  
  • Technology may have advanced since a particular test was undertaken so that genetic issues or inaccuracies which were previously not detectable are now able to be detected by current testing technology (i.e. if the animal was tested again with current technology).  
  • AWA estimates that less than 1% of the pedigree entries, ownership or breeding details in the AWA Herdbook may have errors or which may be misleading. For this reason, users ought to consider if they need to obtain independent testing of the relevant animal (if possible) to ensure that the data is accurate.  

Regarding prefectural content, it is important to appreciate, and you need to be aware that:  

  • Prefectural content is based on the estimation of prefectural origin from Japanese breeding records of 201 foundation sires and 168 foundation dams. As genotype-based parent verification is not used in Japan, and full Japanese registration certificates are not available for all foundation animals, exact prefectural composition for these sires and dams cannot be validated.  
  • The calculation of prefectural content for Australian Herdbook animals relies on the accuracy of pedigree records and DNA samples provided by AWA members.   

Regarding DNA testing and genetic condition results submitted to the AWA, it is important to appreciate, and you need to be aware that:  

  • As genetic testing results are provided by independent DNA testing laboratories at the request of AWA members, AWA relies solely on the accuracy of the reporting of genetic testing as completed by the laboratories.  
  • AWA uses GeneProb software to calculate the likelihood of pedigree animals being a carrier of genetic conditions.  This likelihood is an estimate based on the available genetic testing results.  

If you consider that you do not understand or appreciate the nature and/or implications of the data provided on this website or the WBVs of a particular animal, then AWA strongly recommends that you seek expert advice.  Note there is substantial technical information and articles on the Wagyu website to assist our members. 

AWA’s liability for any loss or damage, consequential or otherwise, suffered or incurred by you or your related business, arising directly or indirectly from your use of Database Information, to the extent permitted by law, is limited to AWA providing you with a refund for the fees paid for the service (if any), or AWA re-performing the service, where possible, at the election of AWA.  

AWA administers this database in good faith to support AWA members and the industry. AWA does not represent or warrant that the animals recorded in this database, or animals breed from them, will achieve any particular genetic or phenotype performance.

THIS DISCLAIMER HAS BEEN UPDATED AS OF 03/02/2026, PLEASE ENSURE YOU HAVE READ IT IN DETAIL

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