Sex hormones are the factors that are involved in the regulation of the protective function of the uterus and its local resistance. The increase in progesterone-estradiol ratio at birth and the postpartum period results for data A.G. Nezhdanov, K.G. Dashukaevа , G.G. Harutа reduced contractility of the uterus for the reducing sensitivity to oxytocin. According to these authors uterus estrogens increase resistance of microflora and progesterone, on the contrary, it decreases, decreasing the synthesis and secretion of proteins in the mother liquor.

Steroidogenesis disorders arise after the morpho-functional lesions of placenta, as evidence of dysfunction of the regulatory reproduction system. With the defeat of placenta is disturbed maternal-placental blood flow. As a result of this inhibition occurs platsentoformations and organogenesis in the fetus. Backlog of placental growth leads to disruption of transport components in the mother-placenta-fetus and the development of acidosis. The adaptive compensatory mechanisms of placental system depleted, disturbed synthesis and metabolism of hormones. Microcirculatory disorders in child and maternal parts of the placenta leads to ischemia in the chorionic villi or edema, and their fusion with the maternal placenta further contributes to the detention of the placenta, the accumulation and development of lochia subinvolution uterus.

The concentration and the ratio of hormones during pregnancy is characterized by its flow, further affects the nature of childbirth and the postpartum period. Cows with metabolic disorders during pregnancy and as a result endocrine disorders, there is a great possibility of slowdown platsentoformations, placental function and fetal organogenesis. Backlog placental development leads to disruption of transport components in the mother-placenta-fetus and the development of acidosis impaired synthesis and metabolism of hormones. Microcirculatory disorders in child and maternal parts of the placenta induce ischemia in the chorionic villi, swelling and promote splicing. Therefore, these blood counts can detect the functional activity of placenta, include the risk of violation of flow of labor, birth and postnatal complications and infertility cows.

Due to this it was necessary to study the endocrine parameters of blood of dead cows on time (60–45 days before the expected birth date ), childbirth and the postpartum period (18–22 days after birth ), describing the function of the ovaries, placenta, thyroid and adrenal glands.

Of the 50 animals included in the physiological experience during pregnancy, birth and the postnatal period was observed in 30 cows, and in 20 (40 %) animals were recorded obstetric disease.

From the data we obtained experimental studies show that the average of both groups of cows figures progesterone, estradiol, and androsterone were significant (P < 0.01) difference only in the animals for 60–45 days before the delivery. At the time of delivery, this trend was not observed. At 18–22 days after birth rate only progesterone was significantly (P < 0.05) different.

Indicators of thyroxin and cortisol in plasma of cows did not significantly change during the dry period , childbirth and the postpartum period. Cows with retention of the placenta , during delivery, thyroxine content was 13 % higher, and cortisol – a 21 % reduction compared to healthy cows. Animals with subinvolution genital and puerperal metritis by 18–22 days after delivery of thyroxin on the contrary, decreased by 25%, and cortisone – a 23% increase compared with healthy cows.

Thus, our studies prove the fact that the pathogenesis of the detention of the placenta, and postpartum metritis subinvolution associated with disorders of steroidogenesis in cows. Characteristic pathogenetic factor is dysfunction of the ovaries and the placenta in dry cows with a reduction in progesterone-estradiol ratio to 2.3:1 (at a rate of 2.5:1), which is due to the reduction of progesterone and estradiol increase in plasma. At the time of delivery in cows with retention of placenta progesterone-estradiol ratio increased to 2.3:1 (at a rate of 1.8:1), which leads to inhibition of contractile function of the muscles of the uterus, it helps to keep atony and placenta.

Inadequate feeding and maintenance of the cows, the lack of physical exercise leads to disruption of metabolism and endocrine dysfunctions. His said, that toriozheniya platsentoformations, lower body resistance to various diseases with impaired function of placenta, placental retention probability of timely delivery, subinvolution genitals and postpartum metritis .

Taking into consideration the fact that all cows have not shown reproductive cycle to 30 days of post-partum period, we believe that increasing of the amount of progesterone in the blood of sick and healthy cows to 18–22 days of postpartum period indicates a violation of innerovaries processes in both healthy and sick cows that what causes anafrodiziyu and infertility.

Key words: fetoplacental complex, progesterone, estradiol, testosterone, cortisol, thyroxine, retention of placenta, metritis and subinvolution.