Hematological parameters of calves of different ages depending on the semen procurement method

The hematological profile of calves born from semen collected using different methods (sexed and traditional semen) was studied, as well as the dynamics of hematological parameters in calves at different physiological stages of development. The experiment was conducted at the L.K. Ernst Federal Research Center for Animal Husbandry and Animal Welfare from 2018 to 2025 and at Agrofirma Zarya LLC in the Nizhny Novgorod Region on holstein heifers. The experiment involved 24 heifers, of which 12 heifers (6 heads per group) were divided depending on the method of semen preparation, and another 12 heads (4 heads per group) were divided depending on the age period (2-6-12 months). Scientific novelty. For the first time, a comprehensive monitoring of hematological parameters (13 parameters) in the blood of calves at different physiological stages of development was conducted, in the same season, and depending on the semen collection method from which they were born. It was established that the semen collection method does not affect the hematological profile for all 13 studied parameters. A comparative analysis of these parameters in calves of different ages revealed statistically significant differences between the 2- and 12-month-old groups in platelet count, mean corpuscular volume, variability of erythrocyte size, and mean platelet volume (P < 0.001). Similar differences were also found between 2- and 6-month-old animals in erythrocyte indices and platelet counts.