Hormonal regulation of reproductive functions of cows and heifers

UDC 619:591.147.8]:636.2.055.082.4

Nazarov M.V., Grin V.A., Gorpinchenko E.A.

Summary. The mechanisms of the influence of the main sex hormones on the sexual cycle of cows and heifers and the effectiveness of their insemination are given. The effectiveness of gonadotropin preparations releasing hormone, prostaglandin and progesterone, used to induce sexual hunting, was studied. The use of combined use of hormones and prostaglandins is effective for synchronizing sexual hunting, regardless of the stage of the sexual cycle on which healthy animals can be at the time of their administration. The reasons for the retention of the yellow body in the ovary are very diverse. The results of the studies indicate that a particularly close relationship exists between the yellow body and the uterus. With various inflammatory processes in the endometrium, myometrium, their injuries, when the afterbirth or parts of the macerated fetus are detained, and in general, if there is any content in the uterus, the ovary may have a yellow body. According to the results of our own research, with the subinvolution of the uterus in cows, the developing follicles undergo luteinization and can turn into a persistent yellow body that causes prolonged anaphrodia. Studies confirmed that in the presence of persistent yellow anamnestic data indicate complete cessation of the sexual cycles. The anatomical and histological structure of the persistent yellow body, and consequently its clinical signs, do not differ from those of the yellow body of the cycle. Therefore, a single study does not give grounds for differentiating the persistent yellow body from the yellow body of the cycle. Such diagnosis is possible only by a two-fold study with a 3-4-week interval. However, infertility disrupts the plans of the farm, so various treatment methods are required for its rapid elimination. A number of authors recommend the use of prostaglandin F2 a (estrofan, estaphalon, etc.), progesterone in combination with gonadotropin. These preperations, which have less therapeutic effect than the use of natural factors, should be applied strictly following the instructions.

Keywords: gonadotropin releasing hormone, prostaglandins, progesterone, sexual cycle, hypothalamic-pituitary system, persistent yellow body, cysts, follicles, egg cell, anovulation, sexual hunting, endometritis, gonadal dysfunction, artificial insemination, reproduction, physiological maturity.

References:

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Author affiliation:

Nazarov Mikhail V., D.Sc. in Veterinary Medicine, Professor, Head of the Department of Anatomy, Veterinary Obstetrics and Surgery of the Kuban State Agrarian University named after I.T. Trubilin; 13, Kalinina st., Krasnodar, 350044.

Grin Vladimir A., Ph.D. in Veterinary Medicine, Head of the Veterinary Department of the city of Krasnodar; 110, Karasunskaya st., Krasnodar, 350910; phone: 8-861-2602794; e-mail: vet@krd.ru.

Responsible for correspondence with the editorial board: Gorpinchenko Evgeniy A., Ph.D. in Veterinary Medicine, Docent of the Department of Therapy and Pharmacology of the Kuban State Agrarian University named after I.T. Trubilin; 70 fl., 17, 70 let Oktyabrya st., Krasnodar, 350044; e-mail: kubeag@mail.ru.