PRODUCTIVITY OF FIRST-HEIFER COWS OF LOCAL BREEDING OF THE HOLSTEIN BREED

There are presented the results of a comparative assessment of milk productivity for 305 days of the first lactation of daughters of the local generation of the Holstein breed of various origins and their mothers, as well as a study of the variability and heritability of milk productivity traits. The studies were carried out in 2020-2021 in the herd of Joint-Stock Company "Aydin", Comrat, Administrative and Territorial Unit Gagauzia, Republic of Moldova. There was established a significant advantage in milk yield of daughters on average for the first lactation over mothers by 530 and 1240 kg of milk, respectively, of Dutch and German breeding, with P <0.001. A weak positive relationship was established between the milk yield and the fat content in milk at the offspring of the local generation of various origins ( r = +0.069) at first-calf heifers of German breeding also have a weak negative relationship (r = -0.186) - first-calf heifers of Dutch breeding. The relationship between milk yield and the amount of milk fat at the descendants of German breeding is positive, the tightness of the relationship is high (r = +0.768), which is significantly greater at P <0.001 than at the descendants of the Dutch breeding - the tightness of the relationship is moderate (r = +0.366). It should be noted the high degree of heritability in milk yield for the first lactation (mother-daughter) of German breeding - 93.0%, Dutch breeding - this indicator is two times lower - 44.8%.