Productivity of Holsteinized black-and-white cattle depending on age

The Ural type of the domestic black-and-white breed is characterized by high productivity and good suitability for use in conditions industrial milk technology. During its breeding, purebred bulls-producers Holstein both foreign breeding continues. As a result conducted research, it was found that cows changes significantly with age. Milk yield 305 days lactation increases from 1 to 3 lactation, then decreases 369 kg or 3.8% fourth, relative third, 2090 22.2% fifth, fourth. full-aged higher than young can remain at level long period. quality indicators changed upward first fifth lactation. High correlation coefficients were established conjugation each other, regardless They ranged 0.364 (2 lactation) 0.533 (1 lactation). That is, decrease increase MJ will lead same change MDB.