Across-breed genomic evaluation based on bovine high density genotypes, and phenotypes of bulls and cows.

Most applications of genomic selection are based on a reference population of bulls only, genotyped with 50k SNP-chips. In some populations, the size of the reference population is limited, resulting in relatively low reliabilities of genomic breeding values. In this study we looked at the possibility of expanding the reference population by combining several breeds in one genomic evaluation, and making use of reference cows in addition to reference bulls. Because such an evaluation needs genotypes at higher density than 50k, high density (777k) SNP-chip genotypes were used. Presentation of results was limited to 7 traits. On average, reliabilities were 1-4% higher than reliabilities from a single breed evaluation using a bull reference population with 50k SNP-chip genotypes, and 0-2% higher than reliabilities from an across-breed evaluation based only on reference bulls and high density genotypes.