Functional state of the ovaries in mammary cows during the period of involution processes after parturition

Abstract

As a result, it was found that the completion of the recovery of the ovarian function (the first ovulation after parturition) in cows is observed within 28.4±7.32-39.3±12.54 days after parturition, and the period from calving to the completion of uterine involution is from 44.5±9.37 to 58.2±10.56 days, depending on the productivity of animals. The maximum fertilization rate in cows with a milk productivity of 15-20 liters/day was 56.7% when they were inseminated in their third heat, in animals with the productivity of 25-30 liters this indicator was significantly lower - 34.7%.

Abnormalities in follicular genesis were revealed, which were characterized by the retardation in the development of follicles, and the absence of a dominant follicle. No yellow body and follicles were found in the ovaries, or, if follicles were found, their diameter ranged from 6 to 10 mm. The ovaries were slightly reduced in size: their length was about-3.21 cm and width-1.85 cm. Thereafter such follicles were subjected to luteinization or atresia.

In the course of studies on the 14th day after parturition, a low level of progesterone was found, almost 2 times (1.27 +0.19 and 0.67 +0.09 nmol/l), in the blood serum of cows with a daily milk yield of 25-30 liters or more. On day 30, the difference in the content of estradiol was 2.4 times (128.41+16.92 and 53.70+ 6.53 nmol/l, respectively) and progesterone-2.9 times (3.53+ 0.22 and 1.2+10.12 nmol/l) in cows in groups with different milk productivity. This indicates the fact that with a low level of progesterone, there is retardation in the recovery of the reproductive function in high yielding dairy cows after parturition due to the functional disorders of the ovaries and focuses on the need to use hormonal regulation during this period.