Genomic selection in dairy cattle

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Genomic selection involves a dense marker map of the genome and the application of a statistical model to simultaneously estimate the effects of every marker or interval between markers. The sequencing of the bovine genome has resulted in the detection of many thousands of genetic markers. Recently, methods have been developed to predict total genetic value of animals using whole-genome dense single nucleotide polymorphism (SNP) marker maps. Selection based on these predicted genomic values is expected to have an enormous impact on breeding programs, but further development is needed to successfully apply this technology to livestock. The estimates of the effects of every marker or interval between markers can also be used to determine the location of potential genes affecting a trait. While simulations demonstrate genomic selection has huge potential to increase rates of genetic gain, results with real data have shown lower response than the prospects. Several key questions remain regarding practical implementation and they should be further investigated, such as density of markers and data structure required for optimum estimation of the effects of markers or chromosome segments, and how the breeding programs should be altered to maximize the gains from genomic selection. This proposal will increase the knowledge about the factors that influence the accuracy of the estimation process and the implementation of genome selection, leading to optimal breeding strategies for this new technology. The overall objectives of the proposal are enhancing methods of genomic selection in dairy cattle, increasing the accuracy of predictions of genomic breeding values, and optimizing dairy cattle breeding strategies through genomic selection.