Infodoc : Sciences, Techniques et Culture

In genomic selection, DNA marker information is exploited for evaluation purposes in large dairy cattle breeds. Most of the current genomic evaluation methods rely today on SNP information, although haplotypes are expected to perform better due to their higher polymorphism. In 2014, genomic evaluation had not yet been implemented in regional breeds (Abondance, Tarentaise, Vosgienne), resulting in economic weaknesses for these breeds.Our aim was to assess the use of haplotypes in genomic evaluation with focus on their performance in combination with multi-breed reference populations. We found that haplotypes outperformed individual SNP markers for genomic evaluation. We also showed that information on haplotype allele frequency and on linkage pattern are relevant to select haplotyp[...]

In genomic selection, DNA marker information is exploited for evaluation purposes in large dairy cattle breeds. Most of the current genomic evaluation methods rely today on SNP information, although haplotypes are expected to perform better due to their higher polymorphism. In 2014, genomic evaluation had not yet been implemented in regional breeds (Abondance, Tarentaise, Vosgienne), resulting in economic weaknesses for these breeds.Our aim was to assess the use of haplotypes in genomic evaluation with focus on their performance in combination with multi-breed reference populations. We found that haplotypes outperformed individual SNP markers for genomic evaluation. We also showed that information on haplotype allele frequency and on linkage pattern are relevant to select haplotypes for evaluation purposes. Our haplotype selection criteria also allowed a significant reduction of the number of markers used for genomic prediction.One of these criteria was incorporated into the French routine genomic evaluation in 2015. The performance of such an evaluation was then assessed in four regional breeds, leading to similar or higher accuracies than current progeny testing. Consequently, routine genomic evaluation was implemented in these breeds in 2016. The use of high density genotypes did not improve the performance of genomic evaluation in these breeds, while multi-breed training populations were beneficial only in some of them. Additional genotyped females led to notable increases in selection accuracies. Inclusion of candidate mutations identified in large breeds led to only minor improvements in regional breeds.