Platelet hemostasis and its relationship with cortisol and progesterone in cows during pregnancy

The assessment of the state of platelet hemostasis in the body of cows of Auliekol and black-and-white breeds in the last trimester of pregnancy and the relationship of its indicators with the level of cortisol and progesterone is given. Laboratory tests were performed 60 and 1-3 days before the expected date of delivery. It was found that the breed of cows affected the level of platelet parameters. At the same time, their value in the blood of cows of the Auliekol breed exceeds the level of animals of the black - and - white breed by 3.15-31.89 %. The dynamics of changes in platelet parameters during the preparation of the mother's body for childbirth is of the same type and is characterized by a decrease in the total number of platelets by 11.74 and 24.14% and their volume fraction in the blood (thrombocrit) by 6.45 and 12.00 %, respectively. At the same time, the average platelet volume, the number of megalothrombocytes and the breadth of their distribution by volume increases by 6.83; 16.37 and 14.94 % (in the Auliekol breed) and 15.49; 16.01 and 17.19 % (in the black-and-white breed). These changes are associated with the level of the hormones cortisol and progesterone, the biological effects of which involve the regulation of platelet aggregation by controlling the level of young cells (megalothrombocytes) in the blood of cows. This is evidenced by statistically significant values of correlation coefficients in pairs of signs: cortisol-P-LGR r=0.72±0.24-0.88±0.17; progesterone-P - LGR r=-0.72±0.24 - -0.83±0.20.