In this research 245 cows are included. They are daughters of ten sires and all of them realized 548 lactations in the period 2000 and 2003. Data used originated from two cattle farms, "Backa" and "Pobeda" that are on government property "Krivaja". During lactation lasting approximately 333 days cow produced 4521 kg of milk yield with 181 kg fat yield and 4,00% fat percentage in standard lactation. The values for heritability are estimated by using interclass correlation. It was low for duration of lactation (0,017) and for fat percentage (0,037). Also, it was medium for milk yield (0,227) and fat yield (0,214).The average values for heritability in the standard lactations were 0,317 for milk yield and 0,281 for fat yield. In other words, those are medium hereditary features. The values for heritability were low for fat percentage (0,031), or low hereditary feature.

In this research 245 cows were included. They are daughters of ten sires, and they realized 548 lactations in the period from year 2000 to 2003. Data were used from two cattle farms, "Backa" and "Pobeda" that are located on government property "Krivaja". In this research influences of systematic factors like farm, year, season or lactation have been included. Breading values are evaluated for all qualities (milk yield, fat yield, fat percentage and persistency of milk production). Sires are ranked based on average milk yield of his daughters.