The Role of Oxidative Stress during Pregnancy on Obstetric Pathology Development in High-Yielding Dairy Cows

The study aimed to examine the processes of oxidative stress and their intensity depending on the state of the antioxidant system in dairy cows. The study was conducted in 2018-2019 on the territory of the Druzhba breeding factory (Voronezh region, Russia) and involved 154 cows divided into 4 groups. Group 1 consisted of healthy animals (n = 83). Group 2 contained animals with afterbirth retention (n = 6). Group 3 included animals with uterine subinvolution (n = 49). Group 4 comprised animals with postpartum catarrhal-purulent endometritis (n = 16). The blood samples were taken from the animals to estimate the content of vitamin E, lipids, malonic aldehyde and enzymes-catalases, reductase and ferroxidase. The concentration of vitamin E in groups 1 and 4 were found to decrease (by 3.9-23.2%; 30.7±2.16-25.9±2.16 compared to 31.9±1.68 μM/L) within two months. The level of malonic aldehyde in group 4 was higher than in other groups after the first month. In one month, its level increased by 20.6% (1.11±0.09 μM/L) by 35.4, 19.4 and 6.7%, respectively (P<0.01-0.001). The exhibited differences indicate the strong significance of functional insufficiency of the antioxidant protection system during the development of oxidative stress during pregnancy and, as a result, the etiology and pathogenesis of parturient and postpartum complications in cows.