Reproductive ability of highly productive Black-Pied Holsteinized cows during year-round same-type nutrition

Abstract

The research goal was to study the reproductive abilities of highly productive cows under the conditions of year-round same-type nutrition on the farm of the OOO “Agro-Sibir” of the Smolenskiy District of the Altai Region. The research targets were Black-Pied Holsteinized first-calf heifers of the second through fourth and more lactations. It was found that in lactating cows with year-round same-type nutrition, with increasing age, the duration of the service period extended by 40 days or more (r = 0.8). With a service period of 130 days or more, the level of milk production decreased by 4% (r = -0.3). The duration of the dry period did not significantly affect the level of milk production (r = -0.1). Metabolic disorders and increasing concentrations of ketone bodies to 1.4-1.6 mmol L contributed to extension of the service period to 100 days or more (r = 0.39).