The relationship of economic and useful traits in the Ural type cows of the black-and-white breed

In the Sverdlovsk region, holsteinized black-and-white cattle of the Ural type are bred. All cows have high productivity indicators; the best milk yields are distinguished by the animals of the Vis Back Ideal line, which surpass their peers by 99 (Reflection Sovering line) and 1477 kg (Montwick Chieftain line) or by 0.9 – 13.7%. In the second case, the difference is significant at P≤0.01. According to the FMF in milk, higher values were observed in cows of the Montwick Chieftain line – 4.03±0.003%. They significantly surpass cows from other lines by 0.04 – 0.07% at P≤0.01, which did not affect the output of nutrients with milk. There is a stable high correlation between cow milk yield and milk fat yield with milk. The correlation coefficients approach one. A negative correlation was found between milk yield and fat mass fraction, which ranged from low (-0.03, Montwick Chieftain line) to medium (-0.34, Vis Back Ideal line). The average positive relationship between the fat mass fraction in milk and the amount of milk fat was found in cows of the lines of the Reflection Sovering and Vis Back Ideal