Dependence of Milk Productivity and Signs of Longevity of Cows of the Holstein and Ukrainian Black-Spotted Dairy Breed on the Length of the Service Period

Abstract

Impact research of the duration of service period on the longevity traits of Holstein and Ukrainian Black-and-White dairy cows was conducted in the herd of private enterprise "Burynske" in Sumy district. It has been established that the milk yield of cows for 305 days and full lactation according to the assessment data of the first, third and best lactations and, in general, for the entire life, grew under the condition of increasing the duration of service period to the level of 140 days, regardless of breed. A further increase in the duration of service period for 141 days led to a decline in the above-mentioned traits. The highest lifetime milk yield was obtained from a group of cows with a service period length of 121–140 days, which amounted to 31955 ± 606.7 kg in Holsteins, and 30188 ± 624.4 kg for Ukrainian Black-and-White dairy breed. Against the background of increase in the duration of service period, rising rates of lifetime, productive use and the number of used lactations was observed in cows of experimental breeds. However, the yield per day of life and productive use decreased in groups of Holstein breed with a service period of ˃ 80–161 < days, from 14.6 to 10.3 kg and from 24.7 to 14.6 kg, respectively. In the groups of cows of the Ukrainian Black-and-White dairy breed with the duration of service period ˃ 80–161 < days, corresponding reduction in milk yield per day of life and productive use amounted to 13.1–9.5 and 21.9–13.2 kg. A direct, medium-level, reliable relationship between the service period length and the traits of lifetime, productive use, milk yield and milk fat during life was revealed, which was within the range of r = 0.193–0.311 in Holstein cows and Ukrainian Black-and-White dairy r = 0.145–0.251. An inverse and highly reliable relationship was found between the duration of service period and the milk yield per day of life and productive use in Holstein cows (r = -0.268 and -0.383) and Ukrainian Black-and-White dairy breed (r = -0.255 and -0.325). The strength of influence the duration of service period of cows on their lifespan, productive use and number of used lactations was 22.4–27.5% for Holstein breed, and 21.4–24.3% for Ukrainian Black-and-White dairy breed. Traits of lifetime milk productivity of Holstein cows depended on the duration of service period by 12.2–31.3% and of Ukrainian Black-and-White dairy cows by 13.4–28.9%.