AGE-RELATED DYNAMICS OF PRODUCTIVE TRAITS IN HOLSTEIN AND ALATAU CATTLE BREEDS
When animals are used under industrial production systems, they must meet specific requirements. Breeders are tasked with developing animals characterized by high productivity, strong constitution, and the absence of conformation defects. The studies were conducted at the private farm “Karimov” in the Zhetysu region. The research objects were cows of the Holstein and Alatau breeds of different ages. A comparative analysis of productive traits of Holstein and Alatau cows of different ages, carried out during 2023–2025, showed that in all age groups and across all years Holstein cows had a clear advantage in milk yield compared with Alatau cows. Thus, the milk yield of first-lactation Holstein cows in 2023 exceeded that of Alatau cows by 2,339 kg (P<0.001), and by 1,254 kg (P<0.001) in cows of the third lactation and older. In 2024, the corresponding advantage was 1,848 kg (P<0.001) and 2,636 kg (P<0.001), while in 2025 it amounted to 1,825 kg (P<0.001) and 2,318 kg (P<0.001), respectively.
The dynamics of milk yield with increasing age differed between the breeds. In terms of qualitative traits, with no statistically significant differences, the Alatau breed showed slightly higher values. The variability of milk yield corresponded to standard reference levels; however, some lability of milk yield was observed in Alatau cows.
It was found that Holstein cows were somewhat larger in body weight. Thus, in the first lactation this advantage amounted to 9 kg, and in full-grown cows to 17 kg (P<0.05). Since Holstein cows significantly exceeded Alatau cows in milk yield per lactation, they also had a higher milk production coefficient: by 23.6% in the first lactation and by 25.4% in full-grown cows.