EN
The analysis was carried out on 67 primiparous cows of different colour sired by blackwhite redfactor (RF) bulls, kept in a modern dairy farm in southwest Poland. The aim of this study was to confirm or reject the hypothesis that the daughters with different colours obtained from redwhite mothers and blackwhite RF bulls may also differ in their milk yield during the first 305day lactation corrected on age and calving season. The cows with different colour were statistically similar with regard to the investigated milk performance traits. Average corrected yield of RF bulls daughters with blackwhite or redwhite colour was respectively 10 300 and 10 112 kg of milk with 4.31 and 4.32% of fat, and 3.08 and 3.13% of protein. The observed relative differences in the range of the investigated milk traits of cows with different colour were not higher than 2%, except for the FPD index. The greatest relative difference between cows with different genotype (below 75.0 and above 75.1.