Expression of high productivity in Ayrshire cows under breeding farm conditions in the Northern European region of Russia

Petrozavodsk State University, Institute of Biology, Ecology and Agricultural technologies, Lenin Str., 33, Petrozavodsk, 185910, Russia

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Abstract

This article presents a comparative analysis of dairy cow productivity on two Ayrshire cattle farms in the Republic of Karelia. The study covers a wide range of quantitative and qualitative milk production characteristics, including milk yield, fat and protein content, live weight, and milk biochemical parameters. It was found that, despite similar feeding and milking conditions, the farms had different milk yields and average milk fat content, as well as differences in protein content and total fat and protein yield. Factors influencing productivity were examined, including housing conditions, feeding technology, animal age, and lactation stage. Significant variability was found in key productivity indicators, particularly milk yield and milk fat and protein production. Cow age was shown to have a significant impact on most economically valuable indicators, with the greatest impact on live weight and milk yield. The chemical composition of milk was analyzed in detail. Significant differences in dry matter and fat content were noted between farms. Correlation analysis revealed typical relationships between key productivity indicators. Particular attention was paid to the assessment of heritable traits. Heritability coefficients (h²) were calculated for various milk components. It was found that the heritability of dry matter, milk fat, and protein varies across farms. The influence of sire genealogical groups on offspring productivity was studied. The obtained results confirm the importance of an integrated approach to dairy herd productivity management, considering both genetic and environmental factors. The results of the study can be used to optimize selection and breeding efforts, improve animal management and feeding practices, and predict changes in the productive qualities of cows depending on age and lactation stage.