PRODUCTIVE LONGEVITY OF THE COWS OF UKRAINIAN BLACK-AND-WHITE DAIRY BREED UKRAINIAN DEPENDING ON HEREDITARY FACTORS
Authors: Shulyar A. L. 
Published: May 2019

A rather low productive longevity of cows, particularly among holsteinized cattle stock, is observed in dairy husbandry of Ukraine.
In the process of creating new dairy breeds in Ukraine, the reduction of cows’ lifespan and productive longevity along with yield increase are observed. The scientists’ research revealed the tendency to cows’ long-term performance reduction under the increasing of the genetic potential of a herd.
It stipulates the topicality of the research as to the search of the effective genetic and selective methods of lengthening animals’ long-term performance.
The goal of the research was to study the indicators of economic use and lifetime productivity of daughters from different bulls, as well as from different cows’ lines of Ukrainian black-and-white dairy breed.
The research was conducted on the materials of a stud farm «Yerchyky» in Zhytomyr oblast which specializes in Ukrainian black-and-white livestock breeding, as well as on using own experimental data.
The indices of cow economic use and lifetime productivity were determined on the ground of the term of rearing, life duration, term of economic use, amount of lactations, the total duration of lactation period, milk yields, milk yield per one lactation day, per life, and per economic use. The reasons for their disposal were determined according to veterinary disposal acts.
The statistical data processing was done using the method of variational statistics. The power of influence of both, the paternity and the linear belonging, was determined by single-factor variance analysis.
Having evaluated the daughters from different bulls of Ukrainian black-and-white dairy breed on a stud farm “Yerchyky”, it has been determined that daughters of Dilaita 542206 had better indices of economic use. They had both, the longest lifespan and the longest economic use, under uncertain distinction between them and the daughters from other bulls.
The number of lactations in daughters from different bulls was low – in the range of 2.0 to 2.5. The coefficient of economic use was in the range of 48.4–50.5%.
A long-life milk yield of daughters of Dilaita 542206 was the highest, but they had absolute advantage only above the half-sisters from stud bulls Virnyi 4975 and Klen 5221. The highest milk yield per lactation day had the daughters of Filder 5573125 (16.6 kg), which is by 2.8 kg more than the milk yield received from the daughters of Virnyi 4975, by 1 kg more than from the daughters of Dilait 5422064, by 2.9 kg more than from the female descendants of Klen 5212.
On a one day basis of economic use, the highest milk yield had half-sisters of Kondon bull 397111, that is by 2.2 kg more than had the daughters of Virnyi 4975, by 1.8 kg more than had the daughters of Klen 5212. Practically there is no difference as to the milk yield of daughters of Dilait 5422064 and that of Fidler 5573215. The descendants of Fidler 5573125 had the highest milk yield per one day of life.
The parameters of economic use and of the lifetime productivity of the cows of Ukrainian black-and-white dairy breed have been studied comparing different lines.
The longest lifespan had the cows of Starbuck line, the cows of Waliant line had the longest economic use under uncertain difference when comparing with the descendants of other lines. The number of lactations was low and ranged from 2.3 to 2.6. The coefficient of economic use of the cows of different lines was within 48.6–54.00%.
The highest life-term milk yield had the cows of Valiant and Vis Burke Aidiala lines. These cows had the best indices of economic use and of lifetime productivity, they had the highest milk yield per one lactation day.
By means of single-factor variance analysis it has been determined that the paternity has a significant impact on the indices of economic use as well as on a linear belonging. A reliable part of bulls influence on the duration of cultivation period makes 7.2%, on milking yield per one day of lactation – 12.6%, on one day of economic use – 4.8%, on one day of life – 4.2%. The influence of linear belonging was lower. A reliable part of linear belonging influence on the duration of cultivation period makes 2.9%, on milking yield per one lactation period – 9.5%, and on one day of economic use – 3.3%.