Effect of intrafollicular administration of PGE2 or PGF2α in early estrus on ovulation, hemorrhagic anovulatory follicles formation, progesterone secretion and pregnancy outcome in the mare.

This experiment was performed to evaluate whether intrafollicular treatment of PGE2 or PGF2α administered in early estrus would induce normal ovulation, progesterone production (Experiment 1) and pregnancy (Experiment 2). In Experiment 1, mares in estrus after 2 days of endometrial edema were injected in all largest dominant follicles (28-35 mm in diameter) with 0.5 mL of sterile water containing 500 µg PGE2 (n = 6), 125 µg PGF2α (n = 6) or placebo (n = 7) (Hour 0). Ultrasound examinations were performed daily, until ovulation or anovulation was detected, and daily blood samples were taken for 8 days. In Experiment 2, mares with a dominant follicle ≥35 mm after at least three days of slight-to-moderate endometrial edema, were injected with 500 µg PGE2 diluted in 0.5 mL of sterile water for injection in the follicle (PGE2 group; n = 9 mares and 11 dominant follicles). No puncture was performed in the control group (n = 9 mares and 11 dominant follicles). Mares from both groups were inseminated. In Experiment 1, all mares (6/6) in the PGE2 group ovulated within 24 h of treatment. The mean interval from intrafollicular injection to ovulation was shorter (P < 0.001) in PGE2 mares (24 ± 0 h) than in control mares (77 ± 9 h). Mares from the PGF2α group developed hemorrhagic anovulatory follicles (HAF) more often (7/7) than control mares (2/7); P < 0.05). The progesterone concentration in mares from the PGF2α group was lower (P < 0.004) than control mares in the early post-ovulatory period. The first significant increase in post-ovulatory progesterone concentration occurred earlier (P < 0.05) in mares from the control group than in mares from the PGF2α and PGE2 groups. In Experiment 2, more mares from the control group (7/9, 78 %) became pregnant than from the PGE2 group (2/9, 22 %) (P = 0.015). In conclusion, PGE2 alone induced follicle collapse in all treated mares within 24 h of administrations, while PGF2α blocked ovulation and induced formation of HAFs. However, the post-ovulatory rise in progesterone production was delayed and the fertility reduced in mares with ovulation induced by PGE2 compared to control mares.

Effects of prenatal cocaine exposure on estrous cycle, and behavior and expression of estrogen receptor alpha and oxytocin during estrus and diestrus in mice offspring.

Increasing evidence indicates that prenatal cocaine exposure may result in many developmental and long-lasting neurological and behavioral effects. The behaviors of female animals are strongly associated with the estrous cycle. Estrogen receptors and oxytocin are important neuroendocrine factors that regulate social behavior and are of special relevance to females. However, whether prenatal cocaine exposure induces estrous cycle changes in offspring and whether neurobehavioral changes in estrus and diestrus offspring differ remains unclear. On gestational day 12, mice were administered cocaine once daily for seven consecutive days, then the estrous cycle was examined in adult female offspring, as well as locomotion, anxiety level, and social behaviors, and the expression of estrogen receptor alpha-immunoreactive and oxytocin-immunoreactive neurons were compared between estrus and diestrus offspring. Prenatal cocaine exposure resulted in the shortening of proestrus and estrus in the offspring. During estrus and diestrus, prenatally cocaine-exposed offspring showed increased anxiety levels and changed partial social behaviors; their motility showed no significant differences in estrus, but declined in diestrus. Prenatal cocaine exposure reduced estrogen receptor alpha-immunoreactive expression in the medial preoptic area, ventromedial hypothalamic nucleus, and arcuate nucleus and oxytocin-immunoreactive expression in the paraventricular nucleus in estrus and diestrus offspring. These results suggest that prenatal cocaine exposure induces changes in the offspring's estrous cycle and expression of estrogen receptor alpha and oxytocin in a brain region-specific manner and that prenatal cocaine exposure and the estrous cycle interactively change motility and partial social behavior. Estrogen receptor alpha and oxytocin signaling are likely to play important concerted roles in mediating the effects of prenatal cocaine exposure on the offspring.

Effect of prostaglandin treatment on the estrus behaviour, follicular and luteal morphometry and serum hormone profile in sub-estrus buffaloes during non-breeding season.

Sub-estrus buffaloes do not exhibit estrus signs despite being cyclic contributing to extended service periods and inter-calving intervals causing significant economic loss. The present study described the effect of synthetic prostaglandin (PGF2α) on estrus behaviour, follicular and luteal morphometry, and serum estradiol (E2) and progesterone (P4) profile in sub-estrus buffaloes during the non-breeding season. The incidence of sub-estrus was 38.4% during the non-breeding season. The sub-estrus buffaloes (n = 33) were divided into two groups, viz., Control (n = 16) and PGF2α treatment (Inj. Cloprostenol 500 µg, i.m., n = 17). Estrus induction response was significantly greater in the treatment (100 vs. 18.75%, p < .001), and a relatively greater proportion of animals conceived in the treatment group (29.41 vs. 6.25%, p = .08). The time elapsed to induction of estrus and insemination following treatment was significantly lower in the treatment group than control. A significant increment in the follicle diameter (9.72 ± 0.45 vs. 13.00 ± 0.45 mm, P < .0001) and serum estradiol (E2) concentration (66.01 ± 11.92 vs. 104.9 ± 13.21 pg/mL, p = .003) observed at the post-treatment period in the PGF2α treatment group. At the same time, CL diameter was reduced significantly at a higher regression rate in the PGF2α treated buffaloes than those of control. Of the responded buffaloes, only 30% showed high-intensity estrus attributed to the expulsion of cervico-vaginal mucus (CVM), uterine tonicity, micturition, and mounting response by a teaser bull. From this study, it can be concluded that the administration of PGF2α could induce estrus in the sub-estrus buffaloes during the non-breeding season. Behavioural changes, along with sonographic observation of POF, regressing CL, and serum E2 and P4 concentration would be useful to determine the right time of insemination in sub-estrus buffaloes during non-breeding season.

Influence of early progesterone removal on follicular development, expression of estrus, and pregnancy rates in presynchronized postpartum beef cows.

The objective of this study was to evaluate the impact of early progesterone removal on pregnancy rates to fixed-time artificial insemination (FTAI) in presynchronized beef cows. Postpartum beef cows (n = 882) were randomly assigned to 1 of 2 treatments: 1) 7&7 Synch: cows received a controlled internal drug release insert (CIDR) and a 25-mg injection of prostaglandin F2α on day 0, 100 µg of GnRH on day 7, a second injection of prostaglandin F2α (PG2) at CIDR removal on day 14, and a second injection of GnRH at FTAI 60-66 h after PG2 (day 17); 2) 7&6 Synch: cows received the same treatment as 7&7 Synch; however, CIDR removal occurred in conjunction with PG2 on day 13, while FTAI remained at 60-66 h after CIDR removal (day 16). Ovarian ultrasonography was performed to determine follicle diameter at PG2 and FTAI in a subset of cows (n = 40). Cows exposed to the 7&7 Synch tended to have larger follicle diameter at PG2 compared with 7&6 Synch cows (P = 0.09); however, there were no differences in follicle diameter at FTAI. No differences were determined between treatments for the expression of estrus (7&7 Synch: 61.6 ± 5.30; 7&6 Synch: 54.1 ± 5.45; P = 0.31) or pregnancy rates to FTAI (7&7 Synch: 60.8 ± 3.83; 7&6 Synch: 57.0 ± 3.84; P = 0.42). In conclusion, early removal of progesterone did not impact pregnancy rates in presynchronized beef cows.

Impact of 17ß-estradiol administration at the moment of timed-AI in Nelore cows with small dominant follicle or not showing estrus.

We aimed to evaluate the effects of administering estradiol (E-17ß) at the moment of timed-AI (TAI) on uterine gene expression, estrous expression rate (EER), and pregnancy rate (P/TAI) in Nelore cows with a small dominant follicle (DF) or not showing estrus at TAI. In Experiments 1 and 2 (Exp1, Exp2) cows were submitted to a P4/E-17ß-based protocol (day 0) for synchronization of ovulation. On day 7, devices were removed, cows received 1 mg E-17ß cypionate and 12.5 mg dinoprost. On day 9, cows with DF < 11.5 mm in diameter were split into different groups. In Exp1 (n = 16/group): Control (no treatment), E-2 (2 mg E-17ß) and E-4 (4 mg E-17ß). In Exp2: Control (n = 12); E-2 (n = 14); GnRH (0.1 mg gonadorelin acetate, n = 13); and E-2+GnRH (association of GnRH and E-17ß, n = 13). Between days 9 and 11, endometrial thickness (ET), time of ovulation detection, and EER were recorded. In Exp1, a uterine cytological sample was collected 4 h after treatment to evaluate the transcript expression of receptors for E-17ß (ESR1 and ESR2), oxytocin (OXTR), and P4 (PGR). In Experiment 3 (Exp3), 3829 suckled cows were submitted to a P4/E-17ß-based protocol for TAI. On day 9, devices were removed and cows received 1 mg E-17ß cypionate and 0.4 mg sodium cloprostenol. On day 11, TAI was performed and cows that did not demonstrate estrus received 0.1 mg gonadorelin acetate, and were allocated into two groups: GnRH (n = 368) and E-2+GnRH (2 mg E-17ß; n = 363). In Exp1, plasma E-17ß concentrations increased at 4 h after treatment in a dose-dependent manner but reduced at 12 h. The E-17ß-treated cows had greater transcript abundance for OXTR and lesser for ESR1 and ESR2, and the ET was reduced 12 h after treatment (P < 0.05). No significant difference (P > 0.1) was observed between the E-17ß doses in estrus or ovulation rate. In Exp2, the interval from treatment to ovulation was longer (P < 0.05) in the E-17ß group. GnRH-treated cows showed higher ovulation rates (89 vs. 35 %) compared to cows not treated with GnRH, as E-17ß-treated cows (P < 0.01) had a lower ovulation rate compared to those not receiving E-17ß (44 vs. 78 %). In Exp3, P/TAI was 55 % for cows in estrus. For those not showing estrus, no difference (P > 0.1) in P/TAI was observed between GnRH (34 %) and E-2+GnRH (31 %) groups. Cows with a DF ≥ 11 mm (n = 192) had a greater (P < 0.05) P/TAI (49 %) than those with DF < 11 mm (n = 377; 29 %). In conclusion, E-17ß administration in the moment of TAI modulates the mRNA expression of uterine receptors in cows with a small DF but does not impact the P/TAI compared with GnRH treatment in suckled Nelore not showing estrus previous to TAI.

Effect of prostaglandin alone and in combination with trace minerals on the follicular and luteal dynamics, estrus response and pregnancy in sub-estrus buffaloes (Bubalus bubalis).

Sub-estrus is a condition when buffaloes do not display behavioural estrus signs, despite being in estrus and causes a delay in conception and increases the service period. The present study describes the effect of synthetic prostaglandin (PGF2α) alone and in combination with trace minerals on the follicular and corpus luteum (CL) dynamics, serum estradiol (E2) and progesterone (P4) concentration correlating estrus response and pregnancy outcome in sub-estrus buffaloes during the breeding season. A total of 50 sub-estrus buffaloes, identified through ultrasonography (USG) examination, were randomly allocated into three groups, viz. T1 (Synthetic PGF2α, Inj. Cloprostenol 500 µg, i.m, n = 17), T2 (Synthetic PGF2α + Trace mineral supplementation, Inj. Stimvet 1 mL/100 kg body weight, i.m., n = 17) and control (untreated; n = 16). Following treatment, 100% of sub-estrus buffaloes were induced estrus in the T1 and T2 groups, while only 18.75% were induced in the control. The CL diameter and serum P4 concentration were significantly lower at post-treatment, whereas the pre-ovulatory follicle (POF) size and serum E2 concentration were significantly higher in the T1 and T2 groups as compared to the control (p < .05). The buffaloes of the T2 group had a greater proportion of moderate intensities estrus than those of T1. Moreover, the proportion of buffaloes conceived in the T1 and T2 were 41.2% and 52.95%, respectively. The larger POF diameter and higher serum E2 concentration were associated with intense intensity estrus and higher conception rate (66.7%) in sub-estrus buffaloes. Similarly, CL regression rate, POF size and serum E2 concentration were relatively higher in the buffaloes conceived as compared to those not conceived. It is concluded that synthetic PGF2α in combination with trace minerals induces moderate to intense intensities estrus in a greater proportion of sub-estrus buffaloes and increases the conception rate during the breeding season. Moreover, behavioural estrus attributes correlating follicle and luteal morphometry, serum E2 and P4 concentration could be used to optimise the breeding time for augmenting the conception rate in sub-estrus buffaloes.

Effects of short and long - term nutrition and progesterone supplementation on the success of fixed - time artificial insemination in the ewe.

The success of fixed - time artificial insemination (AI) in the ewe is variable due to poor synchrony of estrus. We examined the effects of long-term nutrition (LTN; low, medium, high - 6 months), short-term nutrition (STN; 1.0 M, 1.5 M - 14 days) and progesterone supplementation (P; single pessary, replacement on Day 9) on synchrony and reproductive outcomes. High LTN advanced (P < 0.05) estrus, increased (P = 0.06) pregnancy (range 71.1 - 81.1%) and improved (P < 0.01) litter size (range 1.30 - 1.50). STN increased (P < 0.05) pregnancy (79.0 versus 72.3%) but not litter size or timing of estrus. A LTN x STN interaction (P < 0.01) for time of estrus indicates that the effects of LTN were moderated by STN depending on the level of LTN. Pessary replacement delayed (P < 0.05) the onset of estrus, improved synchrony but did not affect pregnancy or litter size. High LTN increased (P < 0.05) the number of large (≥ 3.8 mm) and medium - size follicles (2.0 - 3.7 mm) but the diameter of large follicles tended to be reduced (P = 0.08) on Day 12. STN did not affect follicle number or size whilst P reduced (P < 0.05) the diameter of large follicles on Day 12 (4.83 versus 5.10 mm) and increased the number of medium - size follicles (3.56 versus 2.74 mm). In conclusion, both LTN and STN are major sources of variability in AI programs whilst pessary replacement has potential to reduce variability.

Exposure to topiramate and acetazolamide causes endocrine disrupting effects in female rats during estrus.

BACKGROUND: Idiopathic intracranial hypertension (IIH) is a disease characterized by elevated intracranial pressure (ICP) and is a disease of young females. The first line pharmacological treatments include acetazolamide and topiramate and given the nature of IIH patients and the dosing regimen of these drugs, their effect on the endocrine system is important to evaluate. We aimed to assess the effects of acetazolamide and topiramate on steroid profiles in relevant endocrine tissues. METHODS: Female Sprague Dawley rats received chronic clinically equivalent doses of acetazolamide or topiramate by oral gavage and were sacrificed in estrus. Tissue specific steroid profiles of lateral ventricle CP, 4th ventricle CP, CSF, serum, uterine horn and fundus, ovaries, adrenal glands and pituitary glands were assessed by quantitative targeted LC-MS/MS. We determined luteinizing hormone (LH) and follicle stimulating hormones (FSH) levels in paired serum by ELISA. RESULTS: Topiramate increased the concentration of estradiol and decreased the concentration of DHEA in lateral choroid plexus. Moreover, it decreased the concentration of androstenediol in the pituitary gland. Topiramate increased serum LH. Acetazolamide decreased progesterone levels in serum and uterine fundus and increased corticosteroid levels in the adrenal glands. CONCLUSION: These results demonstrate that both acetazolamide and topiramate have endocrine disrupting effects in rats. Topiramate primarily targeted the choroid plexus and the pituitary gland while acetazolamide had broader systemic effects. Furthermore, topiramate predominantly targeted sex hormones, whereas acetazolamide widely affected all classes of hormones. A similar effect in humans has not yet been documented but these concerning findings warrants further investigations.

Chronic Estrus Disrupts Uterine Gland Development and Homeostasis.

Female mice homozygous for an engineered Gnrhr E90K mutation have reduced gonadotropin-releasing hormone signaling, leading to infertility. Their ovaries have numerous antral follicles but no corpora lutea, indicating a block to ovulation. These mutants have high levels of circulating estradiol and low progesterone, indicating a state of persistent estrus. This mouse model provided a unique opportunity to examine the lack of cyclic levels of ovarian hormones on uterine gland biology. Although uterine gland development appeared similar to controls during prepubertal development, it was compromised during adolescence in the mutants. By age 20 weeks, uterine gland development was comparable to controls, but pathologies, including cribriform glandular structures, were observed. Induction of ovulations by periodic human chorionic gonadotropin treatment did not rescue postpubertal uterine gland development. Interestingly, progesterone receptor knockout mice, which lack progesterone signaling, also have defects in postpubertal uterine gland development. However, progesterone treatment did not rescue postpubertal uterine gland development. These studies indicate that chronically elevated levels of estradiol with low progesterone and therefore an absence of cyclic ovarian hormone secretion disrupts postpubertal uterine gland development and homeostasis.

Leonurine hydrochloride-a new drug for the treatment of menopausal syndrome: Synthesis, estrogen-like effects and pharmacokinetics.

This research aimed to investigate the estrogen-like effects of Leonurine hydrochloride (Leo). First, we developed a total synthesis of Leo from 3,4,5-trimethoxy-benzoic acid and the structure was confirmed through 1H NMR and mass spectrometry (MS). Then the estrogenic activity of Leo in vitro and in vivo was studied. The proliferation and proliferation inhibitory effects of Leo on MCF-7 cells and MDA-MB-231 cells indicate that Leo exerts estrogen-like effects through estrogen receptor α (ERα) and estrogen receptor ß((ERß) in vitro. Uterotrophic assay in juvenile mice showed that Leo has an estrogen-like effect in vivo, as it can promote the development of the uterus of juvenile mice, increase its uterine coefficient and the size of the uterine cavity, as well as the increased number of uterine glands and the thickened uterine wall. For further research, cyclophosphamide (CTX) was used to establish a mouse model of ovarian function decline. Through this model, we found that Leo can restore the estrous cycle of mice, increase the number of primordial and primary follicles in the ovaries of mice, and regulate the disordered hypothalamic-pituitary-ovarian (HPOA) axis of mice. Finally, the pharmacokinetics of Leo was studied and oral bioavailability of Leo was calculated to be 2.21%. Leo was synthesized and the estrogen-like effect in vitro and in vivo was confirmed as well as its pharmacokinetics.

Soy isoflavones alleviate polycystic ovary syndrome in rats by regulating NF- κB signaling pathway.

Soy isoflavones have been widely used in the treatment of clinical gynecological diseases. The aim of this study was to investigate the therapeutic effect and molecular mechanism of Soy isoflavones on rats with polycystic ovary syndrome (PCOS). Sprague-Dawley rats were orally administered 1 mg/kg letrozole for 21 consecutive days to induce the PCOS rat model. After PCOS induction, Soy isoflavones (100 mg/kg) or metformin (Positive control; 500 mg/kg) was administered continuously for 28 days. Then, H&E staining was used to observe the pathological changes of ovary. The serum hormone levels and the levels of antioxidant and inflammatory cytokines in ovarian tissue were detected. Additionally, the expression of NF-κB signaling pathway protein was detected by Western blot. Our results showed that soy isoflavones treatment significantly reduced the body weight, ovarian volume and weight, and improved estrous cycle in PCOS rats. H&E staining showed that the number of cystic dilated follicles and atretic follicles in ovarian tissue diminished, showing healthy follicles and corpus luteum. In addition, soy isoflavones treatment markedly decreased serum testosterone and luteinizing hormone (LH) levels, as well as oxidative stress levels and inflammation levels, and increased estradiol (E2) and follicle stimulating hormone (FSH) levels. At the same time, Soy isoflavones treatment inhibit the phosphorylation level of NF-κB p65 and increased the IκBα expression in ovarian tissues of PCOS rats. Overall, Soy isoflavones can improve ovarian morphology and hormone disorders in PCOS rats by inhibiting the activity of NF-κB pathway and enhancing anti-inflammatory and antioxidant capacity.

Induction of oestrus by administering Inhibin antiserum along with equine chorionic gonadotropin in anoestrous bitches.

As dogs experience oestrus only once or twice a year, it is necessary to establish an effective method of oestrous induction for efficient breeding. In the present study, we evaluated inhibin antiserum (IAS) on oestrous induction in anoestrous females. Bitches were administered 0.5 ml/kg IAS or a mixture of 50 IU/kg equine chorionic gonadotropin (eCG) and 0.5 ml/kg IAS and 500 IU human chorionic gonadotropin (hCG) administered 7 days after the mixture injection. As a control, bitches received 50 IU/kg eCG, with 500 IU hCG administered 7 days after eCG injection. Blood-tinged vaginal discharge, vulvar swelling, plasma progesterone concentrations and ovarian follicular development were assessed from day 0 to day 14. IAS alone injection did not induce oestrus in bitches at the anoestrous stage. Conversely, vulvar swelling, blood-tinged vaginal discharge and an estimated luteinizing hormone (LH) surge appeared on days 3-7, days 3-6 and days 7-9 after the IAS+eCG mixture injection, respectively, in all five bitches at the anoestrous stage. The average number of developing and ovulated follicles in bitches administered IAS+eCG was 8.8 and 9.6 respectively. A single eCG injection followed by hCG induced oestrous signs, with an average of 8.3 developing follicles and 4.5 ovulated follicles. This study revealed that IAS alone did not induce oestrus, but when IAS was used in combination with eCG, it induced oestrus and promoted a considerable number of ovulations in anoestrous dogs.

Effect of exogenous administration of oxytocin on postpartum follicular dynamics, oestrous rate and ovulation in Nili-Ravi buffaloes.

Based on different surveys, dairy farmers are concerned about extensive use of exogenous oxytocin in buffaloes, which is being held responsible for reproductive problems including irregular oestrous cycle and delayed ovulation. For these concerns, effects of oxytocin injection on postpartum follicular dynamics, postpartum oestrous interval (PEI), oestrous length, the interval from onset of estrus to ovulation and blood progesterone (P4) were studied in Nili-Ravi buffaloes. For this purpose, 23 animals within 1 week after calving were randomly divided into three groups: without oxytocin (CON; n = 7), 10 i.u. oxytocin (LOW; n = 8), 30 i.u. oxytocin - (HIGH; n = 8) and used to record the PEI for the study period of 154 days. At subsequent estrus, three buffaloes from each group (not served) were selected randomly to monitor two cycles for 6 weeks. Transrectal ultrasonography was performed to evaluate follicular and corpus luteum (CL) development, and blood sampling was done for progesterone (P4) analysis. These results revealed that postpartum oestrous interval (PEI) decreased significantly in oxytocin-treated groups. The number of small, medium and total follicles on the left ovary was significantly higher in the HIGH group. However, an overall number of small and total follicles on both right and left ovaries was significantly higher in CON and HIGH groups. On the other hand, there was no difference in the number of follicles on the right ovary among all treatment groups. The same was true for the size of pre-ovulatory follicles, CL, P4 concentrations and oestrous cycle length. The intervals from onset of estrus to ovulation and from standing estrus to ovulation were increased considerably in the HIGH group. It is concluded that exogenous oxytocin administration resulted in the shortening of PEI but triggered a delay in ovulation. Moreover, a higher dose of oxytocin could stimulate the growth of small, medium, and total follicles in postpartum Nili-Ravi buffaloes.

Effects of eCG and FSH in timed artificial insemination treatment regimens on estrous expression and pregnancy rates in primiparous and multiparous Bos indicus cows.

Effects were evaluated in Bos indicus cows of eCG and FSH on follicular growth, estrous expression, and pregnancy per artificial insemination (P/AI) as a result of fixed-time artificial insemination (TAI). In Experiment 1, extent of timing-of-ovulation synchronization among cows was evaluated after imposing an estrogen/progesterone-based treatment regimen. At progesterone device removal (D8), cows were administered: eCG, or FSH or served as untreated Controls. In Experiment 2, percentage of cows P/AI was evaluated when the Experiment 1-treatment regimen was imposed. On D10, all cows were artificially inseminated. In Experiment 3, cows were assigned to two treatment groups (Control and eCG) on D8 to evaluate percentage of cows P/AI and estrous expression. In Experiment 1, follicular dynamics were similar among treatment groups. In Experiment 2, follicular growth was greater (P = 0.0001) with the eCG treatment. There was an interaction of treatment × parity (P = 0.007) on percentage of cows P/AI. There was a greater percentage of primiparous cows P/AI in the eCG-treated than Control and FSH-treated cows. There was a greater percentage of eCG-treated multiparous cows pregnant as a result of TAI than Control cows. There was an interaction of treatment × parity (P = 0.005) on P/AI in Experiment 3, in which the eCG effect was more pronounced in primiparous cows. Treatment with FSH, therefore, was not as effective as eCG in stimulation of follicular growth or enhancing percentage of cows pregnant as a result of TAI. Physiological effects of eCG, however, were also more evident in primiparous cows.

Intravaginal administration of estradiol benzoate capsule for estrus synchronization in goats.

Estrus synchronization requires multiple treatments of hormonal drugs, requiring considerable time and cost. The aim of the present study was to develop an estrus synchronization protocol using intravaginal administration of estradiol benzoate (EB) capsules in goats. Two types of capsules were prepared: an EB capsule that melted immediately after administration and a sustained-release (SR) EB capsule that dissolved slowly and reached a peak after 24 h. Goats with functional corpus lutea were intramuscularly treated with prostaglandin F2α (PG). At 24 h after PG administration, goats were administered 1 mg of EB solution intramuscularly (PG + 24IM; n = 6) or 1 mg of EB capsule intravaginally (PG + 24EB; n = 6). The SR EB capsule was administered intravaginally at the time of PG administration (PG + SR; n = 6). The control group (n = 6) received only PG. All groups showed estrus within 72 h after PG administration. The onset of estrus did not differ significantly between the PG + 24IM and PG + SR groups but was earlier than in the control group. Estradiol concentration in the PG + SR group peaked at 11.5 ± 6.1 h after EB and PG administration. Peak estradiol concentrations were not significantly different between the PG + 24IM and PG + SR groups (78.0 ± 25.8 and 64.0 ± 38.1 pg/ml, respectively), and were higher than the PG + 24EB and control groups (27.3 ± 8.8 and 14.6 ± 6.1 pg/ml, respectively). These results suggest that intravaginal administration of an EB capsule with a sustained-drug release base is applicable for estrus synchronization, as an alternative to intramuscular administration.

Differential effects of progesterone on social recognition and the avoidance of pathogen threat by female mice.

Although pathogen threat affects social and sexual responses across species, relatively little is known about the underlying neuroendocrine mechanisms. Progesterone has been speculated to be involved in the mediation of pathogen disgust in women, though with mixed experimental support. Here we considered the effects of acute progesterone on the disgust-like avoidance responses of female mice to pathogen threat. Estrous female mice discriminated and avoided the urinary and associated odors of males subclinically infected with the murine nematode parasite, Heligmosomoides polygyrus. These avoidance responses were not significantly affected by pre-treatment with progesterone. Likewise, brief (1 min) exposure to the odors of infected males attenuated the subsequent responses of females to the odors of the normally preferred unfamiliar males and enhanced their preferences for familiar males. Neither progesterone nor allopregnanolone, a central neurosteroid metabolite of progesterone, had any significant effects on the avoidance of unfamiliar males elicited by pre-exposure to a parasitized male. Progesterone and allopregnanolone, did, however, significantly attenuate the typical preferences of estrous females for unfamiliar uninfected males, suggestive of effects on social recognition. These findings with mice indicate that progesterone may have minimal effects on the responses to specific parasite threat and the expression of pathogen disgust but may influence more general social recognition and preferences.

Effects of immunization against inhibin α-subunit on ovarian structures, pregnancy rate, embryonic and fetal losses, and prolificacy rate in goats where estrus was induced during the non-breeding season.

The objectives of the study were to determine the dose-dependent effects of active immunization against inhibin α-subunit (AIINHA) on ovarian dynamics, concentrations of progesterone (P4), pregnancy rate (PR), embryonic and fetal losses (EFL), and prolificacy during the non-breeding season when there was imposing of a progestin-based treatment regimen to induce estrus in Beetal goats. Goats (n = 30) were randomly assigned into following groups: 1) saline (G-CON-0 mg; n = 10), 2) small dose (G-AIINHA-0.5 mg; n = 10), and 3) large dose (G-AIINHA-1 mg; n = 10). The primary administration of inhibin immunogen was administered at Day -48, followed by another administration at Day -20, and subsequently there was induction of estrus using a progestin based treatment regimen that included a single administration of progestin-containing sponge and PGF2α at Day -8. The sponge was removed, and GnRH was administered at Day -3 followed by breeding (Day 0) at standing estrus. Results indicated mean diameter of the follicles, size of pre-ovulatory follicles and corpora lutea, and post-breeding P4 concentrations were greater (P < 0.05) in the goat does of the G-AIINHA-0.5 than G-CON-0 group. The PR, and EFL, however, did not differ (P> 0.05) among groups, whereas prolificacy rate was greater (P = 0.04) in goat does of the G-AIINHA-0.5 than G-CON-0 groups. The data from this study indicate G-AIINHA-0.5 is the recommended dose of inhibin immunogen to enhance the reproductive performance during non-breeding season in Beetal goats when estrus is induced using a progestin-based treatment regimen.

Histomorphometric and immunohistochemical changes in interstitial cells and ovarian follicles of rats with polycystic ovaries treated with clomiphene citrate.

OBJECTIVE: To evaluate the histomorphometric and immunohistochemical changes in interstitial cells and ovarian follicles of rats treated with clomiphene citrate during and after induction of permanent estrus. METHODS: Twenty four adult-female rats with regular estrous cycle were equally divided into three groups: (1) GCtrl-at estrous phase. (2) GPCOS-at permanent-estrous phase. (3) GCC-PCOS rats, which remained exposed to 60 days of continuous illumination and treated with Clomiphene Citrate. After that, the animals were euthanized, and the ovaries were removed and processed for paraffin embedding. Sections were stained with H.E. for histomorphometry or subjected to immunohistochemistry for Ki-67 and cleaved caspase-3 detections. RESULTS: The GPCOS showed lack of corpus luteum and several ovarian cysts, as well as interstitial-like cells. The presence of corpus luteum and a significant increase in primary and antral follicles were observed in GCC, which also showed a decrease in the number of ovarian cysts and in the area occupied by interstitial-like cells, as well as a decrease in nuclear volume of interstitial cells. The percentage of cell proliferation was significantly higher in granulosa cells of the GCC. On the other hand, the percentage of apoptosis was significantly higher in the granulosa cells of GPCOS than the GCC. CONCLUSION: The ovaries of rats treated with clomiphene citrate showed a decrease in the number of cysts, an increase in the number of ovarian follicles, the presence of corpus luteum along with a decrease in the nuclear volume in the area occupied by interstitial cells.

Seven-week asynchronous twins in a buffalo heifer (Bubalus bubalis) associated with superfetation - A case report.

A female buffalo (Bubalus bubalis) of the Bulgarian Murrah breed aged 1,090 days was observed to give birth to a second newborn (normally developed male) after she had calved (normal female) 49 days earlier. This phenomenon is highly associated with her melatonin treatment within a trial for induction of puberty, the last ear implants being placed approximately 50 days before the assumed date of first mating, to which point the level of progesterone had increased dramatically. Despite none of the matings of the dam was visually witnessed to prove ovulation over an existing gestation, we take the liberty to qualify this phenomenon as superfetation, ruling out the other possible phenomena, namely embryonic diapause as it is highly unlikely to occur in any livestock species, and differentiated development of twin foetuses as it is associated with foetal malformation, which was not observed in this case.

The effect of Gonadotropin releasing hormone administration on fertility and embryonic loss in goats during the anoestrus period

Following the induction of oestrus out of season in small ruminants, low fertility and variations in fertility rates are associated with embryonic losses. One of the main causes of embryonic loss is luteal dysfunction. Gonadotropin Releasing Hormone (GnRH) supports the luteal structure, and increasing progesterone levels may be beneficial in terms of promoting embryonic life. The main objective of the present study was to evaluate the efficacy of GnRH administration following an oestrus induction protocol in the anoestrus season for preventing embryonic loss in goats having failure to conceive during the season. In the study, 106 Damascus goats aged 3-5 years and weighing 45-60 kg were used. The oestrus of 106 goats in the anoestrous group was stimulated with progesterone and pregnant mare serum gonadotropin (PMSG) treatment. Out of breeding season, goats were divided into the 4 following groups: GnRH0 (n = 27), GnRH7 (n = 26), GnRH0+7 (n = 27) and control (n = 26). In each goat, an intravaginal sponge (IS) containing 20 mg of fluorogestone acetate (FGA) was placed into the vagina and left for 9 days. With the withdrawal of the sponge, 550IU PMSG and 125 µg of d-cloprostenol were injected intramuscularly. Oestrus detection was made via teaser bucks for 3 days starting 24 h after withdrawal of the IS. Eighteen bucks known to be fertile were used for breeding. Goats in the oestrus period were mated via natural breeding. The GnRH analogue lecirelin was injected intramuscularly at breeding in the GnRH0 group, on day 7 post-breeding in the GnRH7 group, and both at breeding and on day 7 post-breeding in the GnRH0+7 group. No injections were given to the control group. Blood samples for progesterone measurement were taken by jugular vena puncturing on days 3, 6, 7, 10, 13, 16, and 19 after breeding from 10 randomly chosen goats in all groups. The goats with a level of > 3.5 ng/mL of progesterone on day 21 post-breeding were evaluated as pregnant. Pregnancy was also viewed on day 50 after breeding by real-time ultrasonography (USG) with a 5-7.5 MHz convex probe. The oestrus rate was 96.23% (102/106) in the goats. The rates of onset of oestrus between 36-48 h, 48-60 h and 60 h and beyond were 38.7% (41/106), 21.7% (23/106) and 35.8% (38/106), respectively. The total pregnancy rate was 35.8% (38/106). There were no statistically significant differences (P > 0.05) found for the pregnancy rate, embryonic death rate or progesterone concentration of the groups. However, serum progesterone levels were statistically different in the GnRH7 group compared with the control group (P < 0.05). After synchronisation, various anti-luteolytic strategies can be used to support corpus luteum development and elevate progesterone concentration in the luteal phase to decrease embryonic loss and increase reproductive performance. Therefore, application of GnRH to support the luteal structure and to increase progesterone levels may be beneficial in terms of supporting embryonic life. The results showed that GnRH treatment on the day 7 post-breeding following oestrus induction, including FGA and PMSG, can increase serum progesterone levels in Damascus goats in the anoestrus period. However, following oestrus induction in the anoestrus period, it was seen that GnRH treatment at breeding or on day 7 after breeding did not have any positive effect on embryonic loss or reproductive performance. In conclusion, it was considered that this protocol could be implemented successfully, yielding a 35% pregnancy rate in Damascus goats in the anoestrus period, but embryonic loss must be deeply studied in detail.(AU)