title: Effect of cow reference group on validation reliability of genomic evaluation.
abstract: We studied the effect of including genomic data for cows in the reference population of single-step evaluations. Deregressed individual cow genetic evaluations (DRP) from milk production evaluations of Nordic Red Dairy cattle were used to estimate the single-step breeding values. Validation reliability and bias of the evaluations were calculated with four data sets including different amount of DRP record information from genotyped cows in the reference population. The gain in reliability was from 2% to 4% units for the production traits, depending on the used DRP data and the amount of genomic data. Moreover, inclusion of genotyped bull dams and their genotyped daughters seemed to create some bias in the single-step evaluation. Still, genotyping cows and their inclusion in the reference population is advantageous and should be encouraged.
authors.affiliation: 1Natural Resources Institute Finland (Luke),Green Technology,FI-31600 Jokioinen,Finland.
authors.forename: M
authors.initials: M
authors.lastname: Koivula
authors.affiliation: 1Natural Resources Institute Finland (Luke),Green Technology,FI-31600 Jokioinen,Finland.
authors.forename: I
authors.initials: I
authors.lastname: Strandén
authors.affiliation: 2NAV Nordic Cattle Genetic Evaluation,Agro Food Park 15,8200 Aarhus N,Denmark.
authors.forename: G P
authors.initials: GP
authors.lastname: Aamand
authors.affiliation: 1Natural Resources Institute Finland (Luke),Green Technology,FI-31600 Jokioinen,Finland.
authors.forename: E A
authors.initials: EA
authors.lastname: Mäntysaari
mesh_terms: D000818:Animals; D015982:Bias; D001947:Breeding; D002417:Cattle / Q000145:classification / Q000235:genetics*; D005260:Female; D016678:Genome / Q000235:genetics; D023281:Genomics / Q000592:standards*; D005838:Genotype; D008297:Male; D008957:Models, Genetic; D010641:Phenotype; D012015:Reference Standards; D015203:Reproducibility of Results