Guidelines for Approximating Genomic Reliabilities of the Single-Step Genomic Model

A genomic reliability method developed by the Interbull Working Group on Genomic Reliability Calculation approximated reliabilities of estimated genomic breeding values for the multi-step genomic model as well as the single-step genomic model. Several modifications and improvements have been made thereafter, with a main optimization of making the genomic reliability method feasible for large-scale national genomic evaluations. The calculation of exact reliabilities of direct genomic values was proven to be computational demanding for large, genotyped populations. Therefore, this step of the original genomic reliability method, along with other steps, is no longer required in routine genomic evaluation but it is still needed when a genomic model or a major change in the national model is introduced. Consequently, two guidelines have been developed separately for the routine national single-step genomic evaluation and for deriving genomic effective daughter contribution gain via the Interbull GEBV Test. Detailed technical steps have been described in the new guidelines to assist the countries in applying the methods to the routine single-step evaluation and the derivation of the genomic effective daughter contribution gain parameter in a genomic validation. These guidelines should harmonize the calculation of genomic reliabilities and make the genomic reliabilities of marketed genomic bulls comparable across countries.