Development of heirfers and dairy productivity of cows, doughters of different simmental breed bulls

Scientific-economical experiment on animals of Simmental cattle combined (dairy-meat) breed was carried out in TzOV «Litynske». A retrospective analysis was conducted and the milk productivity of cows and daughters of different bulls was studied. The growth of repair heifers, half-sisters by father was studied. The genealogical structure of the herd in TzOV «Litynske» is represented by three lines. To improve the genealogical structure of the herd, selected cows and heifers of mating age in the period from 2017 to 2020 were inseminated by purebred elite bulls, in particular: Imago 9727 (Redad’s line 711620016.77), Wikht 75771 (Horror’s line 809706945.79) of German breeding and Obrii 938 (Streif’s line 120081.78) of Austrian breeding. The growth and development of young Simmentals of combined (dairy-meat) breed of three lines was studied. Live weight was quite high in animals of all studied lines, which is typical for animals of Simmental combined breed. However, in all the studied periods there is a trend of higher live weight in heifers, daughters of the bull Imago 9727. Studies have shown that the formation and manifestation of milk productivity signs of cows was significantly influenced by their parents and belonging to the line. Thus, the analysis of the obtained data shows that the daughters of the bull Imago 9727 are characterized by higher milk productivity. Thus, yields of the first-born cows were 4297 kg of milk. In the first-born cows of other comparable groups this figure was lower by 983 kg, or 22.9 % (daughter of Wikht 75771), 279 kg, or 6.5 % (daughter of Obrii 938). The advantage by yield for the second lactation was observed in cows, daughters of the bull Imago 9727. Yield was higher by 740 kg, or 16.0 % (daughter of Wikht 75771), 392 kg, or 8.5 % (daughter of Obrii 938). Among adult cows, the predominance by yield was also observed in the offspring of the bull Imago 9727. The difference compared to the daughters of Wikht 75771 and Obrii 938 was 634 kg, or 12.2 % and 534 kg, or 10.3 %. The fat content in milk in the studied groups ranged from 3.69–3.87 % for the first, 3.74–3.83 % for the second and 3.71–3.85 % for the third lactation. The coefficient of variation in the milk yield was in the range from 19.8 to 48.0 %, the fat content in milk ‒ 6.0–13.5 %.