Inclusion of genomic information in the development of economic index for dairy cattle selection

Abstract

Selection indexes are restricted to traits easily measured and related to high heritabilities. This way, the use of molecular information on these may result in gains in accuracy and selection response, mainly due to the inclusion of a larger number of traits and molecular markers information. Thus, the aim of this research is to incorporate genomic information in the development of economic indexes. Phenotypic and genotypic data of productive and functional traits from 2000 Hostein dams will be used. The economic values will be constructed bases on five breeding objectives (production, quality, reproduction, health, maintenance) and three payment scenarios (milk yield, dairy products, nutritional quality). Economic weights will be estimated by the partial derivative of the profit function for each trait evaluated at the average of the others. Breeding values prediction will be based in two approaches: traditional and genomic, in which the relationship matrix is replaced by a modified matrix that combines genomic and pedigree information. The prediction model will include the fixed effects of contemporary groups, days in milk and lactation class, the additive genetic random effects and the residual effect. The methods will be compared for the genomic values prediction, animals ranking, accuracy and mean squared error. Equally, the economic indexes for sire selection will be evaluated by rank correlation, reliability and selection response. (AU)