estradiol-3-benzoate and Anovulation

The objective of this experiment was to determine if incorporation of kisspeptin-10 (Kp10) into treatment with estradiol benzoate (EB) and sulpiride to induce early cyclicity would result in greater endocrine responses and a greater number of mares responding with either follicle(s) > 30 mm or ovulation within 25 days of treatment. Eighteen anestrous mares were blocked by breed, body condition, and age before random assignment to treatment or control. All mares received 50 mg EB before receiving osmotic minipumps containing either saline (n = 9) or Kp10 (50 μg/hour; n = 9) one day later. The next day, all mares received 3 g sulpiride. Serial blood sampling occurred after pump placement and continued daily for 25 days. Transrectal ultrasounds were performed regularly to monitor ovarian activity. Data were analyzed by Student's t-test or ANOVA with repeated measures. Seven Kp10-treated mares responded compared to only 4 saline-treated mares. Mean days from sulpiride treatment to ovarian response was less in Kp10-treated mares (13.7 ± 1.1 d, P ≤ 0.01) compared to saline-treated mares (35.9 ± 7.8 d). Plasma prolactin increased (P < 0.001) in response to sulpiride in all mares; however, prolactin was higher (P < 0.05) in Kp10-treated mares. Plasma LH increased in all mares beginning 5 days after sulpiride but was greater (P < 0.0001) in Kp10-treated mares. Plasma FSH concentrations did not differ between groups. In conclusion, incorporation of Kp10 potentiated the prolactin and LH responses to EB-sulpiride and resulted in more mares responding with early ovarian activity.

Topics: Animals; Anovulation; Estradiol; Female; Follicle Stimulating Hormone; Horse Diseases; Horses; Kisspeptins; Luteinizing Hormone; Ovulation; Prolactin; Sulpiride

The present research sought to determine whether the administration of estradiol benzoate and long-acting progesterone to anovulatory recipient mares could maintain the pregnancy after embryo transfer during the autumn transitional phase. Recipient mares (n = 40) received the hormonal supplementation (treated group) whereas the other 36 served as a control. The control group consisted of mares having typical estrous cycles with ovulations, development of a viable corpus luteum and received one transferred embryo 5 days after ovulation. Hormonal administrations in the treated group started 8 days before the embryo transfer. During the first 3 days, the mares received estradiol benzoate (5 mg the first day, 3 mg the second day and 2 mg the third day). At Day 5 subsequent to ovulation, the mares received one administration of 1500 mg long-acting progesterone, and the same treatments occurred at the day of embryo transfer. Afterwards, treated mares also received 1500 mg long-acting progesterone every 7 days until 120 days of gestation. For both control and treated groups, the recipient mares were classified as acceptable, marginally acceptable or unacceptable for embryo transfer, and the embryo quality was also determined. The pregnancy diagnosis in recipient mares was made at Days 13, 30 and 60 of pregnancy. While the pregnancy rate was greater (P < 0.05) in the treated than in the control group, the recipient classification did not influence pregnancy rates. In conclusion, pregnancy in anovulatory recipient mares during the autumn transitional phase can be achieved when estradiol benzoate and progesterone are administered.

Topics: Animals; Anovulation; Breeding; Delayed-Action Preparations; Dose-Response Relationship, Drug; Drug Administration Schedule; Embryo Transfer; Estradiol; Female; Horses; Insemination, Artificial; Pregnancy; Pregnancy Maintenance; Pregnancy, Animal; Progesterone; Seasons; Treatment Outcome

Many mammals, including cattle, can develop ovarian follicular cysts, but the physiological mechanisms leading to this condition remain undefined. We hypothesized that follicular cysts can develop because estradiol will induce a GnRH/LH surge on one occasion but progesterone exposure is required before another GnRH/LH surge can be induced by estradiol. In experiment 1, 14 cows were synchronized with an intravaginal progesterone insert (IPI) for 7 days, and prostaglandin F(2alpha) was given on the day of IPI removal. Estradiol benzoate (EB; 5 mg i.m.) was given 3 days before IPI removal to induce atresia of follicles. Cows were given a second EB treatment 1 day after IPI removal to induce a GnRH/LH surge in the absence of an ovulatory follicle. All cows had an LH surge following the second EB treatment, and 10 of 14 cows developed a large-follicle anovulatory condition (LFAC) that resembled follicular cysts. These LFAC cows were given a third EB treatment 15 days later, and none of the cows had an LH surge or ovulation. Cows were then either not treated (control, n = 5) or treated for 7 days with an IPI (n = 5) starting 7 days after the third EB injection. Cows were treated for a fourth time with 5 mg of EB 12 h after IPI removal. All IPI-treated, but no control, cows had an LH surge and ovulated in response to the estradiol challenge. In experiment 2, cows were induced to LFAC as in experiment 1 and were then randomly assigned to one of four treatments 1) IPI + EB, 2) IPI + GnRH (100 microg), 3) control + EB, and 4) control + GnRH. Control and IPI-treated cows had a similar LH surge and ovulation when treated with GnRH. In contrast, only IPI-treated cows had an LH surge following EB treatment. Thus, an initial GnRH/LH surge can be induced with high estradiol, but estradiol induction of a subsequent GnRH/LH surge requires exposure to progesterone. This effect is mediated by the hypothalamus, as evidenced by similar LH release in response to exogenous GnRH. This may represent the physiological condition that underlies ovarian follicular cysts.

Topics: Administration, Intravaginal; Animals; Anovulation; Cattle; Cattle Diseases; Estradiol; Female; Gonadotropin-Releasing Hormone; Hypothalamus; Luteinizing Hormone; Ovarian Cysts; Ovarian Follicle; Ovulation; Progesterone