New algorithm for calculating EBV Accuracies (TBLUP

The large number of genotypes included in the TransTasman Angus Cattle Evaluation adds considerable complexity to the computation demands required for the successful operation of the genetic evaluation. To address the increased computation complexity, staff at the Animal Genetics & Breeding Unit (AGBU) have developed new, more efficient algorithms for the calculation of EBVs and the associated EBV accuracy values. The new algorithm for calculating EBVs, known as TBLUP, was introduced into the TransTasman Angus Cattle Evaluation as part of the annual enhancements in December 2020. A new algorithm for calculating the accuracy value that is published alongside each EBV is now scheduled for implementation in December 2022. The new algorithm for calculating EBV accuracy values has several advantages, including: · Efficiency: The new algorithm is more efficient and will cater for the large number of genotypes that are likely to be submitted for inclusion in the TransTasman Angus

Cattle Evaluation in future years. · Speed: The new algorithm is faster and provides considerable savings in memory usage and run time, enabling the bi-monthly schedule for the TransTasman

Angus Cattle Evaluation to be maintained.

Figure 3 – More efficient algorithms have been developed to cater for the large number of genotypes now being included in the TransTasman Angus Cattle Evaluation

· Precision: The new algorithm is more precise in describing the data that is contributing to the estimation of the breeding value. The new algorithm for calculating EBV accuracy was implemented into the genetic evaluations conducted by Sheep Genetics Australia for the Merino, Terminal and Maternal breeds in May 2022, and will now be progressively introduced to the BREEDPLAN genetic evaluations conducted for other beef breeds both domestically and internationally.

The new algorithm will result in some changes to the EBV accuracy values that are published for Angus animals. Animals most impacted will be those with genomic information and limited trait recording, and non-genotyped relatives of genomically tested animals. The new algorithm will not result in any changes to the EBVs that are published, only the EBV accuracy values.