The signs of milk productivity of cows bred in different climatic zones depending on the year and season of their birth

Abstract

Data on the influence of environmental factors on the milk productivity formation of cows in different climatic zones of Ukraine are presented. It was established that animals bred in the steppe zone had the highest milk yield, milk fat content, and milk fat output, and animals from the Polissia zone had the lowest values. Among the cows from different breeding zones, intergroup differentiation was also observed by milk productivity depending on the year and season of their birth. In the forest steppe zone, the highest productivity was noted for the first-calf heifers born in 2011, in the Polissia and steppe zones — for the animals born in 2015, and for the third lactation in all breeding zones, the cows born in 2015 were the most productive. A curvilinear intergroup differentiation based on the characteristics of milk productivity was also noted between animals with different seasons of birth. The highest milk yields at “Oleksandrivske” State Enterprise and “Named after Volovikov” Joint Stock Company LLC were obtained from the first-calf heifers born in the autumn period, and at Research Farm “Askaniiske” Research State Enterprise — from animals born in summer. During the third lactation, the cows born in autumn were the most productive in all breeding zones and whose first calving occurred in the steppe zone in the spring period, in the forest steppe and Polissia zones — in autumn. The year of birth and the breeding zone had the most significant effect on fertility and fat content in milk, and it was stronger in first-calf heifers, and the season of birth of animals had the least effect on signs of milk productivity.