The study was aimed to determine the relative variability of breeding values of Holstein bulls from different countries of origin (USA, Canada, Germany , and the Netherlands) used in Ukraine, as well as the level of agreement between foreign evalu a tions and national re-evaluations. The d ata from 220 imported bulls whose semen was used for herd reproduction in 2020 – 2021 were analyzed. Domestic evaluations were expressed as estimated breeding values (EBV) , calculated using a national methodo l ogy, whereas foreign evaluations were generally obtained using BLUP-based models. The analysis included milk yield, fat and protein content and yield, number of daughters and herds, and reliability . Foreign evaluations were based on substantially larger datasets, which resulted in higher reliability (94–97%) compared with 86–93% in Ukraine. The average breeding values for milk yield and fat and protein yields in the USA and Canada exceeded the Ukrainian estimates (by 250–350 kg for milk yield, up to 45 kg for fat, and up to 28 kg for protein), while the actual performance of daughters was similar. In contrast to the EBV estimates, the breeding value for milk production for German sires evaluated in Germany was mostly negative. Correlations between Ukrainian and foreign evaluations were moderate for Canadian bulls (r = 41–55%; P < 0.001), weak for American bulls (r ≈ 20%; P < 0.05), and in significant for German bulls. Significant relationships were observed only for quantitative traits (milk yield), whereas no statistically significant correlations were found for fat and protein percentages. North American selection indices exceeded Ukrainian ones by 1.5–2 .0 times, while the German index had negative values. The breeding value of imported bulls varies depending on the country of origin and the evaluation methodology. The highest agreement between Ukrainian and foreign results was observed for Canadian sires, moderate agreement for American sires, and no agreement for German sires. Foreign evaluations should be used only as a preliminary reference, whereas final selection requires mandatory national re-evaluation considering local conditions.
