(new) Chapter 8.16: Key issues on ranking the animals

Estimated breeding values provide estimates of the genetic potential of animals and indicate their potential value as parents.
Estimated breeding values are based on regressing genotypic information on the phenotype.
1. Better quality of phenotypic information and better quality of the regression coefficient both improve the estimated breeding value.
2. Accuracy of the estimated breeding value indicates how likely it is that the estimation breeding value resembles the true breeding value.
Mass selection involves ranking the animals based on their own performance.
1. Repeated observations add to the accuracy of mass selection.
The animal model allows for incorporation of information on relatives in estimating breeding values.
1. Often BLUP is used for the estimations. It combines information on relatives and allows for cleaning of the phenotypic data from systematic effects.
2. Accuracy of information on relatives depends on the heritability and the number of relatives. In case of sib information, the presence of a common environmental effect may reduce the accuracy of estimated breeding values.
Genomic selection combines phenotypes and extensive SNP genotypes of a reference population, and uses the resulting associations to estimate breeding values for other animals with SNP genotypes.
1. Allows for accurate EBV at very young age.
2. Useful for phenotypes that are difficult or expensive to measure.
3. The reference population needs to be of sufficiently large size and requires regular updating.