Data #
Single Nucleotide Polymorphisms (SNPs) are analyzed using the Illumina Bovine Genotyping BeadChip platform. SNPs that exhibit more than 10% missing genotypes or whose rarer allele frequency is less than 0.01 are excluded when selecting SNPs for evaluation.
Phenotypic data comes from deregressed conventional breeding values (EBV – Estimated Breeding Value), supplemented by the effective number of daughters (EDC) and the relatedness of individuals.
Model #
Direct genomic breeding value (DGV) #
Direct Genomic Value (DGV) is based on a single-trait linear mixed model with a random additive SNP effect, using de-regressed conventional breeding values as the dependent variables and SNP genotypes as the independent variables for individuals as specified in point 4.1 directly or through imputation from other genotyping platforms. The evaluations are weighted by the effective number of daughters (EDC).
Genomic enhanced breeding value (GEBV) #
The Genomic Enhanced Breeding Value (GEBV) is calculated as an index composed of the conventional Breeding Value (EBV) or, in its absence, the Pedigree Index (PI) and the Direct Genomic Value (DGV) assessment, weighted by their accuracy.
Repeatability of evaluation #
Direct genomic breeding value (DGV) #
The accuracy (repeatability) of the Direct Genomic Value assessment (DGV) is approximated by the accuracy realized based on Interbull validation.
Genomic enhanced breeding value (GEBV) #
The accuracy (repeatability) of the Combined Breeding Value (GEBV) for evaluated animals is estimated based on the accuracy calculated for DGV and EBV or PI.
Indexes and Sub-Indexes #
Genomic Breeding Values are combined into sub-indexes and a selection index based on the principles described in the section devoted to conventional evaluation.
Publication Conditions for Genomic Evaluation #
The international Combined Genomic Breeding Value is published, and in its absence, the national Genomic Breeding Value. The condition for publication is the accuracy value of the estimates for production traits, which cannot be less than 0.5.