Genomic evaluation by single-step procedure allows efficient implanting of genetic SNP markers into complicated procedure of random regression test-day-model of milk traits. Test-day records and pedigree files on nation-wide scale are combined with genomic relationship into common evaluation of both genotyped and ungenotyped animals. Due to strong import of foreign sperm into small national populations is the reliability of evaluation of young animals low. This is particularly seen in evaluation of young bulls, which frequently have both parents foreign. Genomic evaluation helps and notably improves reliability of evaluation. ssGBLUP procedure is advantageous especially for small populations. Domestic genomic evaluation of young animals has medium to high correlation with foreign Interbull values. Interbull conversion of values of bulls according MACE, which works with progeny tested bulls, is more reliable than conversion according GMACE procedure, which works with genomic evaluation of young animals. Keywords: genomic breeding value, ssGBLUP, test day model, MACE, GMACEReferencesBauer, J. et al. (2014) Approximation of the reliability of single-step genomic breeding values for dairy cattle in the Czech Republic. Anim. Sci. Papers and Reports, 32, pp. 301-306.Bauer, J., Přibyl, J. and Vostrý, L. (2015) Contribution of domestic production records and Interbull EBV on approximate reliabilities of single-step genomic breeding values in dairy cattle. Czech J. Anim. Sci., 60, 263-267.Christensen, O.F. and Lund, M.S. (2010) Genomic prediction when some animals are not genotyped. Genet.Sel.Evol. 42, pp. 2.Forni, S., Aguilar I. and Misztal, I. (2011) Different genomic relationship matrices for single step analysis using phenotypic, pedigree and genomic information. Genet. Sel. Evol., 43, pp. 1.Legarra A., Aguilar I. and Misztal, I. (2009) A relationship matrix including full pedigree and genomic information. J. Dairy Sci., 92, pp. 4656-4663.Meuwissen, T.H.E., Hayes, B.J. and Goddard, M.E. (2001) Prediction of total genetic value using genome-wide dense marker maps. Genetics, 157, pp. 1819–1829.Misztal, I., Legarra A. and Aguilar, I. (2009) Computing procedures for genetic evaluation including phenotypic, full pedigree, and genomic information. J. Dairy Sci., 92, pp. 4648–4655.Pešek, P., Přibyl, J. and Vostrý, L. (2015) Genetic variances of SNP loci for milk yield in dairy cattle. J. Appl. Genet., 56, pp. 339-347.Plemdat, (2015) Descriptions of Breeding values Evaluation. Retrieved on 10th June 2015 From www.plemdat.cz.Přibyl, J. et al. (2014) Domestic and Interbull information in the single step genomic evaluation of Holstein milk production. Czech J. Anim. Sci., 59, pp. 409-415.Přibyl, J. et al. (2015) Domestic estimated breeding values and genomic enhanced breeding values of bulls in comparison with their foreign genomic enhanced breeding values. Animal, 9, pp. 1635-1642.Vitezica, Z.G. et al. (2011) Bias in genomic predictions for populations under selection. Genet. Res. (Camb), 93, pp. 357-366.Zavadilová, L., Jamrozik, J. and Schaeffer, L.R. (2005a) Genetic parameters for test-day model with random regressions for production traits of Czech Holstein cattle. Czech J. Anim. Sci., 50, pp. 142-154.Zavadilová, L., Němcová, E. and Wolf, J. (2005b) Definition of subgroups for fixedregression in the test-day animal model for milk production of Holstein cattle in the CzechRepublic. Czech J. Anim. Sci., 50, pp. 7-13.Zavadilová, L. et al. (2014) Single-step genomic evaluation for linear type traits of Holstein cows in Czech Republic. Anim. Sci. Papers and Reports vol. 32, pp. 201-208