Productive longevity of cows of dairy breeds depending on the duration of their first service period

Abstract

Recently, in the breeding and commodity farms of our country can be observed a rapid decrease in the duration of productive use dairy cattle. A considerable amount of scientific researches are conducted on the effects of hereditary and environmental factors on productive indicators longevity, researches are done on various ways to increase durability productive use of dairy cattle. In this aspect, reproductive ability of cows is important, which must be taken into account while individual estimation for the next selection of the most valuable animals that combine high milk productivity with high fertility. Therefore, the goal of our research was to study the productive longevity of dairy cows depending on the duration of their first service period and find the optimal duration of this indicator for a particular breed. The research was carried out on cows of Holstein, Ukrainian Black-and-White and Red-and-White breeds. Retrospective analysis of duration and the effectiveness of life-time use of cows was carried out according to the method Yu P. Polupan (2010). It was found that average duration of the first service-period of cows was 167.7 days on the studied Holstein populations, 180.3 – on the Ukrainian Black-and-White and Ukrainian Red-and-White – 142.1 days. The longest duration of life, productive use, lactations and the highest milk yields had cows with the duration of the first service period of 121–150 days among the Holstein breed, 151–180 – Ukrainian Black-and-White and 91–120 days and Ukrainian Red-and-White. The worst, by the indicators of productive longevity, were individuals with 60 days and no more of the first service period. Correlation analysis showed the different level of the connection between the duration of the service period animals and indicators of their lifelong use, which in most cases had a reverse nature. This kind of connection indicates that with the extension of the duration of service period of cows, the duration of their productive use and lifetime productivity decreases. In Holstein breed animals, the correlation coefficients between the above named indicators ranged from -0.462 to 0.370, Ukrainian Black-and-White – from -0.113 to 0.144 and Ukrainian Red-and-White – from 0.279 to 0.149. Strength of influence of the duration of the first service-period on life duration, productive use and lactation of cows, depending on the breed, was 12.5–36.5%, for lifetime productivity – 9.7–34.6 and on the one day of life, productive use and lactation – 11.3–35.9%.