Variance components and genetic parameters for first lactation were estimated using Schaeffer`s Pseudo-REML method in mixed model equation(MME). Variance components were estimated with the data of 596 First lactation records which had been gathered at the National Animal Breeding Institute from 1970 to 1988. Analyzed traits were 305-day milk yield, fat yield and fat percentage. Iteration numbers for estimation were 42, 29, and 31 at milk yield, fat yield and fat percentage in convergence criteria of 1 × 10^-5, respectively. Heritabilities estimated from sire variance components in mixed model equation were 0.333, 0.245, and 0.178 for milk yield, fat yield and fat percentage, respectively. Estimates of genetic correlation were 0.782 between milk yield and fat yield. -0.596 between milk yield and fat percentage. and 0.086 between fat yield and fat percentage.