How is the genomic value used in Estimated Breeding Values?

Relationship approach 

In a relationship approach, such as the TBLUP model that is used TACE through BREEDPLAN, or the APY model that is used in the World Angus Evaluation, the incorporation of genomics is about relationships between animals. 

• In its simplest form, a breeding value is calculated by  
  • a) estimating the relationship between an animal and other animals in the genetic evaluation 
  • b) using the performance information that has been collected for the animal and the animals to which it is related to predict an animal’s breeding value. The more closely an animal with a phenotype is related to a target breeding animals whose breeding value is of interest, the more influence that its performance has on the breeding value being calculated. 
• In traditional, pedigree based genetic evaluation, the relationships between animals are determined by pedigree alone. 
• In a genetic evaluation that incorporates genomics, the relationships between animals are determined by combining pedigree and genomic information. 

The manner in which genomics is incorporated into industry genetic evaluations is referred to as a ‘single-step’ genetic evaluation, reflecting that genomics data is analysed simultaneously with other sources of information (e.g. pedigree and phenotypes) to calculate a single, genomically enhanced breeding value.