Best linear unbiased prediction was used to estimate breeding values and allele effects on 305-d milk yield. The analysis data had 851 lactation records from 409 cows, 642 animals in the pedigree, 31 groups of herd-year-month of calving, and 5 groups of Holstein fractions (50%, 50.1 to 75.0%, 75.1 to 87.5%, 87.5 to 93.75%, and >93.75%).