Alternative forms of testing the antioxidant blood status of cows at different stages of the reproductive cycle

The purpose of the study was to study the indicators of the pro- and antioxidant blood systems of cows at different stages of the reproductive cycle (30th day after calving (control), 3rd, 5th, 7th, 8th months of pregnancy, 7–10- 1 day before calving, 10–15 days after calving) using an enzymatic colorimetric test to correct housing and operating conditions. Scientific research was carried out on the basis of JSC "Rassvet" in the Lyubinsky district of the Omsk region. The total pro- and antioxidant capacity of blood serum was determined using an enzymatic colorimetric test on the Multiscan device. The study revealed a significant decrease in blood pro-oxidative capacity starting from the 3rd month of pregnancy with a tendency towards an intensive increase in the pre- and post-calving periods. The antioxidant capacity of blood serum reaches critically low values by the 5th month of pregnancy, begins to increase in deeply pregnant cows, decreases towards calving, and in the post-calving period tends to control values. The data obtained indicate that the maximum intensity of free radical processes is observed in cows 7–10 days before calving and on the 15th day after calving. Antioxidant protection of the body decreases as the pregnancy period increases; in the last months and before calving, there is a tendency to increase it.