Productive traits of black- and -white cows of different lines

The article presents the research results concerning the productive characteristics of black-and-white first-calf cows in the context of their genealogical lines. The research has been conducted in 2021 and involved 1187 black-and-white first-calf cows. The conducted research has made it possible to identify the genealogical lines for further improvement of the herd. The Pabst Governer 882933 line cows have had the highest milk yield over 305 days of the first lactation, that has reached 7729 kg. The Reflection Sovering198998 line, the Vis Back Idial 1013415 line,the Montwick Chieftain 95679 line and the Siling Trajun Rokita 252803 line animals have turned out to be inferior to the best group by 263 kg (P≥0.99), 307 kg (P≥0.99), 731 kg (P≥0.999) and 1152 kg (P≥0.999), respectively. The following animals have given milk with a high mass fraction of fat: the Reflection Sovering 198998 line animals - 4.05%, the Vis Back Idial 1013415 line animals - 4.04%, the Pabst Governera 882933 line animals - 4.01%. A low fat content has been found in the milk of the Siling Trijun Rokita 252803 line cows - 3.78%. The Pabst Governer 882933 line cows and the Reflection Sovering 198998 line cows have given milk with the highest yield of milk fat, 310 and 302 kg respectively. The average indicator for the herd has been 300 kg, the Vis Back Idial 1013415 line animals have had the same indicator; the Siling Trajun Rokita 252803 line cows have shown the lowest indicator - 249 kg. The Pabst Governer 882933 line cows (530 kg), Reflection Sovering 198998 and Vis Back Idial 1013415 line cows (529 kg) have been distinguished by the largest live weight. The sample average has been 528 kg. The Siling Trijun Rokita 252803 and the Montvik Chieftain 95679 line animals have had the smallest live weight of 514 kg. The highest coefficient of milk production has been observed in cows of the Pabst Governer 882933 line - 1458 kg, the lowest coefficient - in the Siling Trijun Rokit 252803 line cows - 1279 kg.