Assessment of the economically beneficial traits of mature cows of Holsteinized black-motley breed

Abstract

Holstein is one of the most widespread dairy breeds in the world. In Russia, the most popular is black-motley breed, which has been improved over the past four decades through crossbreeding with the best world Holstein breed. The study aimed to investigate the productive traits of young replacement cows and cows of different years of birth of Holsteinized black-motley cattle of the Ural type. An increased intensity of rearing of young replacement animals was found to reduce the age of first fruitful insemination, to increase productivity, namely milk yield per lactation, and to reduce the length of the productive life of cows. Intensive rearing of young replacement animals has reduced the age of fruitful insemination by 5.7 months over seven years, particularly in the last 2 years, relative to the indicators observed in 2012. With age, the cow productivity changes insignificantly and remains at sufficiently high level. The study revealed that the genetic potential of the parents and intensive rearing of young replacement animals provide a steady increase in milk production of first-calf heifers. However, productivity of cows in subsequent lactations either remains stable or decreases. Productivity of cows increases in second (2013–2015) and third (2012) lactations and then starts to decline. With age, the length of the lactation service period reduces by 5.2–34.9 days, which is primarily due to synchronization of reproductive cycles with an economically viable waiting period implemented on commercial farms. Reproductive cycle synchronization has been implemented in the region since 2015, which immediately reduced the length of the cow service period.