Milk productivity of cows depending on their origin on genealogical line

Abstract

The improvement of cattle of Black-and-White breed by mating of maternal stock with the sires of Holstein breed continues at the present time. Therefore, breeding in pedigree farms for the production of milk is carried out including the use of Holstein lines. The purpose of the work was to assess the milk productivity of cows of Black-and-White breed, with a high proportion of blood in Holstein breed, depending on their linear origin. In the herd of the breeding farm where the research has been carried out, the lines Reflection Sovereign 198998 and Wes Ideal 933122 occupy the dominant position in terms of the specific weight of cattle, followed by the line Montwick Chieftain 95679. The difference in milk yield between groups of cows of different lines was from 3,0 to 354 kg or 0,04 to 4,6 %. The highest milk yield was shown by the first-calf heifers of the line Wes Ideal 933122 – 7787±123,21 kg. In the milk of the first-calf heifers of the line Pabst Governor 882933 compared with herdmates of other lines the increased content of fat and protein has been noted,. The difference in the mass fraction of fat in milk was significant in favor of Pabst Governor 882933 cows (P ≤ 0,01–0,001). There was also the significant difference in the mass fraction of fat in milk between the groups of cows of the lines Montwick Chieftain 95679, Reflection Sovereign 198998 and Wes Ideal 933122 in favor of the latter at P ≤ 0,05–0,01. A definite association between milk yield and the mass fraction of fat in milk has not been established. There is a pattern of the positive association between the mass fraction of fat and the mass fraction of protein in milk and it is clearly seen that with the increase in the mass fraction of fat in milk, there is the increase in the mass fraction of protein.