Comparative assessment of the dynamics of milk productivity of black and white holstinized breed cows over five years on a farm in the Leningrad region

Abstract

The current work analyses dynamics and key indicator changes in milk productivity and development in a livestock of 857 first heifers in a breeding cattle farm in Leningrad Region between 2017 and 2021. In the five years the share of high-producing animals (over 10000 kg of milk per. 305 days) in the first lactation period increased. A growth in milk fat and protein levels and increased milk yield rate were also witnessed. Mass fraction of fat increased 0.03% by 2021 compared to 2017. Mass fraction of protein gradually increased over the five years and was 3.22% by 2021, up 0.06% from 2017. The amount of milk fat increased by 6%, and the amount of protein also gradually increased, and by 2021 was 7.6% higher than the initial figure. There was a slight decreased in a first-heifer weight (by 2.8%). The share of first-heifers with milk production above 10000 kg per lactation increased by 18.5% from 2017 to 2021, and the yield increased by 6%. There is a correlation between the milk yield and the number of high producing cows yielding over 10000 kg during a lactation period. A comparative evaluation with the standard of the breed showed that the average milk production exceeded the standard by 111%, the mass fraction of fat – 115%, the mass fraction of protein – 0.18%, the amount of milk protein – 133.6%, the development (weight) – 23%. The collected data signify focused selection work carried out in the farm and are likely to result from the use Holstein bull-improvers.