Reproductive capacities of heifers taking into account their disease rate during the milk period of development

The work was carried out in the laboratory of cell engineering of the Federal State Budgetary Scientific Institution FRC VIZh named after L.K. Ernst, on the basis of Agrofirma Zarya LLC, Bogorodsky District, Nizhny Novgorod Region, in herds with a milk productivity of 8100 kg of milk per lactation, in the period 2017-2021. The reproductive abilities of 495 heifers were studied in the experiment. Depending on the semen procurement method, the calves were divided into two groups: Group I (n = 244) - calves obtained from semen harvested in the traditional way (TPS); Group II (n = 251) - calves that were obtained from inseminations with semen separated by sex (RSS). The health of the calves was observed during the lactation period, from birth to two months of age. Gastrointestinal tract (GIT) diseases and respiratory diseases (RDS) were taken into account. All data were statistically processed using Microsoft Office Excel software. Average values (M), errors (m), and variability (min-max) were studied. Reliability was calculated using the Student's t-test. It was found that during the observation period, 80.8% of calves were healthy, including 78.5% in Group II and 83.2% in Group I. The incidence of GIT diseases in Group I was 10.9%, RDS - 8.3%, and in Group II, these figures were 12.4% and 9.2%, respectively. Fertile insemination occurred in an average of 52.8% of heifers, including 56.7% in Group I and 48.7% in Group II. Abortions in group I were recorded in 5.1%, in group II – in 3.5% of animals.