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This study determined the effects of administering a glycoprotein with equine chorionic gonadotropin (eCG)-like activity (eCG-like) on corpus luteum (CL) area, serum progesterone concentrations, incidence of multiple ovulations (MOV), estrus expression rate (EER), and pregnancy to timed AI (P/TAI) in Angus cattle synchronized with a 5-d Co-Synch protocol. On Day −8, cattle were body condition scored (BCS), and received a 1.0 g progesterone intravaginal device (IVD) and 100 μg GnRH. On Day −3, the IVDs were removed and 500 μg cloprostenol was administered intramuscularly (i.m.). Cattle were randomly assigned into one of two groups: eCG-like (heifers, n = 232, primiparous, n = 148, and multiparous cows = 485; 300 IU (heifers) and 400 IU (cows) eCG-like i.m. on Day −3), or Control (heifers, n = 240, primiparous, n = 151, and multiparous cows, n = 478; no eCG-like). On Day −2, cattle received a second dose of 500 μg cloprostenol, and on Day 0, 100 μg GnRH was given concurrently with TAI. Estrus expression rate was assessed by observing the tail paint rubbed off in a subset of heifers (n = 372) and all cows on Day 0. Transrectal ultrasonography was used to evaluate the presence of CL on Day −8 and to diagnose P/TAI on Day 30–35. In a subset of cattle (heifers = 194 and multiparous cows = 87), CL area, serum progesterone concentrations, and incidence of MOV were evaluated on Day 7. Heifers, primiparous, and multiparous cows were analyzed separately. Treatment with eCG-like did not affect (P > 0.1) EER in heifers. Estrus expression rate was increased (P ≤ 0.03) in primiparous (68.9 % vs 45.0 %) and multiparous (75.5 % vs. 68.8 %) cows treated with eCG-like compared with Controls. Pregnancy/TAI was increased (P < 0.01) in heifers (65.2 % vs 48.3 %) and primiparous cows (48.3 % vs. 35.1 %) treated with eCG-like than Controls. In multiparous cows with a BCS ≤4 P/TAI was increased (P = 0.03) in the eCG-like group (47.7 %) than the Control group (34.8 %) but was similar (P > 0.1) between treatment groups in multiparous cows with a BCS ≥4.5. The eCG-like treatment increased (P < 0.05) CL area in heifers and multiparous cows and tended (P = 0.10) to elevate serum progesterone concentrations only in heifers. However, it did not affect (P > 0.1) the incidence of MOV in heifers and multiparous cows. Glycoprotein eCG-like administration increased fertility in heifers and primiparous cows, but in multiparous the effect of eCG-like on fertility was associated with BCS. eCG-like treatment in a 5-day Co-Synch synchronization protocol: • Increases estrus expression rate in primiparous and multiparous cows. • Increases P/TAI in heifers, primiparous cows, and multiparous cows with a BCS ≤ 4. • Increases CL area in heifers and multiparous cows. • Does not affect the incidence of multiple ovulations in heifers and multiparous cows. [ABSTRACT FROM AUTHOR]

This study aimed to evaluate the effects of different doses of equine chorionic gonadotropin (eCG; 200 and 300 IU) administered at the end of a fixed-time artificial insemination (FTAI) treatment protocol on ovulation, pregnancy, and twin rates in Bos taurus beef heifers. In addition, pregnancy losses in heifers with singleton and twin pregnancies were determined. A total of 2382 Angus heifers treated with a 6-day estradiol/progesterone-based protocol for FTAI (J-Synch protocol) were randomly allocated to two experimental groups to receive 200 or 300 IU of eCG administered intramuscularly at the time of intravaginal progesterone device removal; FTAI was performed from 60 to 72 h after device removal. The pregnancy rate did not differ (P = 0.89) between the 200 and 300 IU eCG groups. The number of corpus luteum induced by both eCG doses was determined by ultrasonographic examination 14 days after insemination and those treated with 300 IU of eCG had a greater double ovulation rate (P < 0.05). In addition, 300 IU eCG treated heifers had a higher twinning rate on day 30 of gestation (P < 0.05) and parturition (P < 0.05). Pregnancy losses from 30 days of gestation to calving did not differ between heifers treated with 200 and 300 IU of eCG (P = 0.70). However, regardless of the experimental group, heifers bearing twins had greater pregnancy losses than heifers with singletons (P < 0.05). In conclusion, reducing the dose of eCG from 300 to 200 IU under FTAI treatment protocol decreases double ovulation and twinning rates, maintaining a similar pregnancy rate in heifers. Nulliparous cows carrying two fetuses suffer greater pregnancy losses than cows with singletons. • Different doses of eCG were evaluated in a progesterone-based protocol for FTAI. • Reducing from 300 to 200 IU eCG maintained similar P/AI. • Twinning rate was lower with 200 IU eCG. • Those heifers bearing twins, suffer greater pregnancy losses than singletons. [ABSTRACT FROM AUTHOR]

Background: Estrus synchronization is widely used in ovulation induction in dairy ewes in the non-breeding season. Objectives: This study aimed to investigate the differences in reproductive performance between cyclic and Anestrus Lacaune dairy ewes in synchronization protocol using a vaginal implant of progesterone and equine chorionic gonadotropin (eCG) in non-breeding season programming. Methods: Eighty-four 15 to 20 months old Lacaune ewes were chosen, with one delivery, and 90 days had at least passed. Two blood samples were taken for progesterone (P4) evaluation 10 days apart. Plasma P4 concentrations were determined using an ELISA. Ewes with P4<1 ng/mL in two blood samples were considered acyclic and compared with cyclic ewes in estrus expression, pregnancy rate, lambing rate, litter size, fecundity, birth weight, and sex of lambs. The ewes were kept in a separate place about 5 km away from the rams for >2 months. Results: Out of 84 ewes, 31 were cyclic (36.90%), and 53 were anestrous (63.10%). In anestrous ewes, mean P4 concentrations were 0.43±0.4 and 0.45±0.04 ng/mL in the first and second blood sampling, respectively. In cyclic ewes, mean P4 concentrations were 2.46±0.39 and 2.77±0.34 ng/mL in the first and second blood sampling, respectively. Expression of behavioral estrus did not differ between anestrous and cyclic ewes (P>0.10). The pregnancy and lambing rates tended to be greater in cyclic ewes than in anestrous ewes (odds ratio (OR)=3.35; 95% CI, 0.88%, 12.77%; P=0.08). Litter size, fecundity, birth weight of lambs, and offspring sex ratio were not different between anestrous and cyclic ewes (P>0.10). Conclusion: The cyclic ewe using synchronization protocols outside the breeding season could cause high pregnancy and lambing rates compared to Anestrus ewe. [ABSTRACT FROM AUTHOR]

Background: Equine embryonic loss following the development of endometrial cups delays return to cyclicity due to the production of equine chorionic gonadotropin (eCG). Natural degradation of endometrial cups coincides with an influx of immune cells at 100–120 days of gestation, but therapeutic stimulation of reduced eCG production has been relatively unsuccessful. Recently, we observed an increase in pro‐inflammatory cytokine production following the use of the immunostimulant mycobacterium cell wall fraction (MCWF). Objectives: To evaluate the efficacy of hysteroscopic‐guided injection of MCWF on the accelerated decline of eCG secretion. Study design: In vivo experiment. Methods: Mares were pharmacologically aborted at 40–45 days of gestation, and then divided into groups: MCWF‐treated (6 mg MCWF suspended in 20 mL LRS; n = 10) and Control (20 mL LRS; n = 6). Five days after abortion, hysteroscopic‐guided injection of endometrial cups was performed, with 1 mL of volume placed into each visible endometrial cup. This was repeated 7 days later. Trans‐rectal ultrasonography was performed to monitor ovarian activity, and serum was obtained to assess eCG and cytokine concentrations. Results: Concentrations of eCG decreased in the MCWF‐treated group (p < 0.01) with a significant suppression noted as early as 14 days after onset of treatment and remained suppressed for the duration of the study. This coincided with an increase in peripheral IFN‐γ (p < 0.01) and IL‐1β (p < 0.01) concentrations. Eight out of ten MCWF‐treated mares (80%) developed pre‐ovulatory follicles, in comparison to 2/6 controls (33%). A pre‐ovulatory follicle was noted 23 ± 4 days after onset of treatment. Main limitations: No pregnancy data was obtained following treatment. Conclusions: This is the first report of a treatment for the accelerated reduction of eCG following abortion. Stimulation of this process allowed mares to develop a pre‐ovulatory follicle within a month of MCWF treatment onset, granting repeat attempts at breeding within the confines of a single breeding season. [ABSTRACT FROM AUTHOR]

This study evaluated the efficacy of the administration of different doses of equine chorionic gonadotropin (eCG; 0 IU, 200 IU, or 300 IU) at the time of the progesterone device removal in 2‐year‐old Nelore (Bos indicus) heifers synchronized for fixed‐timed artificial insemination (FTAI). On day 0 (D0), a total of 398 heifers received 2 mg of oestradiol benzoate i.m., 0.53 mg of cloprostenol i.m., and an eight‐day previously used (second use) intravaginal device containing 1 g of progesterone (P4). Eight days later (D8), simultaneous with the P4 device removal, 0.5 mg of oestradiol cypionate i.m. and 0.53 mg of cloprostenol i.m. were administered. At the same time, heifers were randomly assigned to receive one of the following treatments: G‐0 IU (n = 141; no eCG treatment), G‐200 IU (n = 132; treated with 200 IU of eCG), and G‐300 IU (n = 125; treated with 300 IU of eCG). FTAI was performed 48 h after the P4 device removal (D10). Ultrasonographic evaluations were performed at D0, D10, and D17. Heifers were scanned to measure the size of the largest follicle (LF), the presence, number, and size of the corpus luteum (CL), and the ovulation rate. Subsequently, at D40, the heifers underwent scanning to determine the pregnancy rate and identify any twin pregnancies. Additionally, at D70, scans were performed to assess pregnancy loss (PG). Data were analysed by orthogonal contrasts [C1 (eCG effect): control x (200 IU + 300 IU) and C2 (eCG dose effect): 200 IU × 300 IU]. On D0, CL presence was similar between the groups [G‐0 IU = 65.2% (92/141), G‐200 IU = 55.3% (73/132), and G‐300 IU = 63.2% (79/125); p =.16]. No interactions between the presence of CL on D0 and eCG treatment were found for any of the variables (p >.05). The diameter of the LF at FTAI (D10) was not influenced by eCG treatment (p =.22) or eCG dose (p =.18). However, treatment with eCG increased the diameter of the CL at D17 (G‐0 IU = 15.7 ± 0.3 mmb, G‐200 IU = 16.6 ± 0.2 mma, and G‐300 IU = 16.6 ± 0.3 mma; p =.001), regardless of the dose used (p =.94). The ovulation rate was higher in heifers treated with eCG [G‐0 IU = 79.4%b (112/141), G‐200 IU = 90.2%a (119/132), and G‐300 IU = 93.6%a (117/125); p =.002], but there was no effect of eCG dose (p =.36). Pregnancy per AI (P/AI) on D40 [G‐0 IU = 32.6%b (46/141), G‐200 IU = 42.4%a (56/132), and G‐300 IU = 42.4%a (53/125); P = 0.05] and D70 [G‐0 IU = 29.1%b (41/141), G‐200 IU = 40.9%a (54/132), and G‐300 IU = 40.8%a (51/125); p =.02] were higher on heifers that received eCG; however, no dose effect was observed for P/AI on D40 (p =.89) nor D70 (p =.98). Pregnancy loss between D40 and D70 tended to reduce (p =.07) in eCG‐treated heifers without dose effect (p =.91). Heifers with CL at D0 presented a greater follicle diameter (LF) on D10 (With CL = 11.2 ± 0.2 mm and Without CL = 10.2 ± 0.2 mm; p =.05), CL diameter on D17 (With CL = 15.8 ± 0.03 mm and Without CL = 11.8 ± 0.6 mm; p =.01), and ovulation rate [With CL = 95.5% (233/244) and Without CL = 74.7% (115/154); p =.01]. However, no difference in pregnancy rate at D40 (p =.52) and D70 (p =.84) was found. In conclusion, eCG treatment increases ovulation and pregnancy rates of heifers submitted to a FTAI protocol. Furthermore, eCG treatment increases the diameter of the CL after FTAI and reduces pregnancy losses. No dose effect was observed, suggesting Nelore (Bos indicus) heifers respond to 200 IU of eCG treatment for FTAI. [ABSTRACT FROM AUTHOR]

High indicators of reproductive function in rabbits can be achieved using hormonal inducers of ovulation, in particular analogs of gonadotropin-releasing hormone, serum, and chorionic gonadotropins. Therefore, the aim of this study was to evaluate the dynamics of sex hormones in the blood serum and meat of rabbit does during ovulation stimulation over 5 consecutive pregnancies. For this purpose, 60 Hyla rabbit does were randomly divided into five groups of 12, ensuring four animals per group with three replicates. Animals of the first and second experimental groups, animals received intramuscular injections of serum gonadotropin, 40 IU and 25 IU respectively, three days prior to artificial insemination. Females of the third and fourth groups were administered combined doses of serum and chorionic gonadotropins (40 IU and 24 IU, respectively) during the same period. Rabbits of the control group were stimulated to ovulate by subcutaneous injection of 0.2 ml analog of gonadotropinreleasing hormone after artificial insemination. Long-term administration of gonadotropins revealed dose-dependent effects. Hyperprogesteronemia was detected in rabbit does (40 IU), while hyperandrogenia was noted in females (24 IU) during the combined administration of gonadotropins. The use of serum gonadotropin at a dose of 25 IU contributed to an increase in the level of follicle-stimulating, luteinizing hormone and progesterone while decreasing 17ß-estradiol. A high dose (40 IU) in rabbit does did not cause significant fluctuations of hormones in blood serum, but decreased luteinizing hormone and progesterone. Long-term use of a gonadotropin-releasing hormone analog was accompanied by a pronounced decrease in the level of luteinizing hormone, as well as 17ß-estradiol. However, the meat of all experimental animals did not increase the content of steroid hormones (testosterone and 17ß-estradiol). It can be concluded that ovulation stimulation in rabbit does using a serum gonadotropin dose of 25 IU and the recommended dose of a gonadotropin-releasing hormone analog does not negatively impact the hormonal balance. [ABSTRACT FROM AUTHOR]

The aim of this study was to investigate the effect of replacing equine chorionic gonadotropin (eCG) with human chorionic gonadotropin (hCG) and also improving the efficiency of hCG using a slow-release compound (alhydrogel) on the reproductive performance of Afshari ewes after laparoscopic artificial insemination. For this purpose, 48 Afshari ewes (2.5-4 years old with the mean weight of 68±2.5kg and an body condition score of 3.04±0.3 were treated with intravaginal controlled internal drug release (CIDR) for 14 days. The ewes were then divided into 4 groups: the first group: injection of eCG (400IU), 48 hours before CIDR removal (eCGS), the second group: injection of eCG (400IU) combined with alhydrogel, 48 hours before CIDR removal (eCGSR), the third group: injection of hCG (400IU), 48 hours before CIDR removal (hCGS) and the fourth group: injection of hCG (400IU) combined with alhydrogel, 48 hours before CIDR removal (hCGSR). The results showed that there was no significant difference between eCGSR and eCGS treatments in Measured parameters (P>0.05). The lowest pregnancy rate (25%) and fecundity (33%) were recorded in related to the hCGS treatment. However, in the hCGSR treatment, these parameters were increased to the values recorded in eCGSR and eCGS treatments. The results of this study showed that hCG in the presence of slow release compound can be a suitable substitute for eCG in the estrus synchronization protocol based on progesterone and eCG. [ABSTRACT FROM AUTHOR]

To use an evidence-based approach to evaluate the available research data on the efficacy of equine chorionic gonadotropin (eCG) to improve reproductive performance of dairy cows when added to oestrus synchronisation programmes for the treatment of cows not detected in oestrus. A rapid literature review was conducted to summarise the existing trial data, primarily the effect of eCG on conception rate (CR) to fixed time artificial insemination (FTAI) from oestrus synchronisation programmes in lactating dairy cows. Relevant papers were identified via databases and auxiliary search strategies, then information was collected using a standardised data collection form. Similar studies were grouped together to create a descriptive summary of CR to FTAI and secondary outcome measures, with the creation of forest plots to visualise results. A total of 15 studies were identified for review: nine examined the administration of 400–500 IU eCG as part of an oestrus synchronisation programme based on intra-vaginal progesterone-releasing devices, gonadotropin-releasing hormone and prostaglandin (P4-GPG programme). The variable methodologies in the trials evaluated posed difficulties in grouping studies for further analysis and meant that there was insufficient data for a full meta-analysis. A single study reported a statistically significant increase in CR to FTAI from the addition to eCG to a P4-GPG programme in cows with anovulatory anoestrous. Four studies evaluated the addition of eCG to P4-GPG programmes in cows without visible oestrous signs; risk differences for CR to FTAI were between −1.7% and 28.8%, with three out of four studies reporting a positive effect of eCG on CR to FTAI, but all 95% CI values crossed the line of no effect. Two studies reported on the effect of eCG on 42-day pregnancy rate following a P4-GPG programme; one reported a risk difference of −4.9% (95% CI = −10.6–0.8%), while the other reported a risk difference of 7.9% (95% CI = 0.8–15%). The results of published studies describing the effect of eCG in P4-GPG programmes on CR to FTAI are inconsistent and further well-designed, adequately powered studies with standardised outcome measures are required to investigate its effect. [ABSTRACT FROM AUTHOR]

In order to assess the effect of equine chorionic gonadotropin (eCG) administered on Day 5 or 7 of a fixed-time artificial insemination protocol (FTAI) in anestrous suckled beef cows, two experiments were performed to determine the following endpoints: Experiment 1 (n = 22), preovulatory follicle (POF) diameter, ovulation time, corpus luteum (CL) area, estradiol (E2) and progesterone (P4) concentrations; and Experiment 2 (n = 676), a field trial to evaluate conception rate using the same experimental design. In both experiments, a synchronization protocol using estradiol benzoate (EB) (Day 0), intravaginal progestin device (IVD) (Days 0 through 7), prostaglandin (PGF) (Day 7), eCG (Day 5 or 7), and GnRH (Day 9). Treatment consisted of administering 400 IU of eCG on Day 5 (T5) or Day 7 (T7 or control) concomitant with treatment with PGF2α. In experiment 1, all cows of T5 ovulated by 16 h after GnRH administration. The POF tended (P = 0.06; P = 0.07) to be larger at 1 and 2 d before ovulation in T5. The day before ovulation, E2 tended to be lower (P = 0.06) in T5 compared with T7. The CL area and the P4 concentrations were greater (P = 0.04) on day 9 in T5 compared with T7. In experiment 2, the conception rate was greater (P = 0.04) in T5 (72.2%) compared with T7 (61.0%) group. Therefore, administration of eCG on Day 5 of the designed protocol hastened ovulation of a greater follicle, which produced a larger CL and greater concentrations of progesterone by Day 9 after ovulation, resulting in 11.2% increase in cows pregnant. • Use of eCG on Day 5 of the protocol hastens the ovulation of a larger follicle. • Anestrous cows receiving eCG on Day 5 have lower estradiol at 24h before ovulation. • Use of eCG on Day 5 improves ovulation synchrony in anestrous suckled beef cows. • Cows receiving eCG on Day 5 have larger CL and produces more progesterone after ovulation. • Use of eCG on Day 5 increases pregnancy rate in anestrous suckled beef cows. [ABSTRACT FROM AUTHOR]

This study evaluated the effect of equine chorionic gonadotropin (eCG) and factors such as body condition score (BCS), cyclicity, and breeding season in a controlled internal drug release (CIDR)-based oestrus synchronization protocol on ovarian follicle dynamics, oestrus expression, ovulation rate, and pregnancy per artificial insemination (AI) (P/AI) in Nili-Ravi buffalo. Adult buffaloes (n = 88), 6.69 ± 1.17 years, parity 3.36 ± 0.97, and BCS 2.76 ± 0.45, were randomly administered eCG or saline, concurrent with prostaglandin F2α (PGF2α) treatment on Day 6 in a CIDR synchronization protocol during the breeding season and low breeding season. Follicular dynamics and oestrus expression were recorded from eCG administration until ovulation. Fixed-time artificial insemination (FTAI) was performed at 48- and 60-hour intervals after CIDR withdrawal. On Day 35 post-AI, pregnancy was diagnosed with ultrasonography. There was no significant difference in the size of the ovulatory follicle between eCG-treated buffaloes (ETB) and saline-treated buffaloes (STB). The growth rate of the dominant follicle, oestrus response and intensity, ovulation, and P/AI were higher (P <0.05) in eCG-treated buffaloes. It was concluded that eCG improved the growth rate of the dominant follicle, oestrus expression, and P/AI in a CIDR-based FTAI programme in Nili-Ravi buffalo. The deleterious effects of poor BCS, acyclicity, and low breeding season could be reduced with a progesterone-based fixed time AI protocol with the addition of eCG. [ABSTRACT FROM AUTHOR]

The aim of this study was to investigate the effects of maternal, hormonal, and fetal factors on early fetal volume (FV) measurements in mares obtained by three-dimensional (3D) ultrasound. Furthermore, postpartum parameters were explored in regard to their association with early FV. For this purpose, 149 German warmblood mares that were artificially inseminated and confirmed to be pregnant between days 14–16 of gestation, were examined transrectally at day 45 ± 1 of gestation with the portable 3D ultrasound device Voluson® i (GE, Zipf, Austria). FV was calculated by using the extension software Virtual Organ Computer-aided AnaLysis (VOCAL™). Two different mixed linear models were used to analyze associations between the investigated maternal and fetal factors and the FV. Explanatory variables investigated in the first model were: maternal age, parity, maternal weight, and body condition score, type of pregnancy (recipient or biological mother), barren status (lactating or non-lactating), fetal sex, progesterone (P4) and equine chorionic gonadotropin (eCG) concentrations; and in the second model outcome variables such as gestational length, birth weight, placental weight, fetal sex, and abortion were included in the analysis. The final models revealed a significant relation between FV and eCG (b = 0.011, P = 0.030), as well as with P4 (b = −0.053, P = 0.016), but interestingly P4 was negatively related to FV. Fetal sex showed the most prominent effect on FV (b = −0.256, P = 0.039), with female fetuses being smaller than male fetuses. In the second model none of the investigated parameters were related to early FV except for fetal sex (b = -0.328, P = 0.047), again with female fetuses being smaller. In summary, it was found that FV is related with eCG, P4 and fetal sex, but was no suitable predicting factor for the investigated outcome parameters. Furthermore, the findings suggest that sex specific growth differences exist already in early gestation. The detailed biological mechanism by which P4 and eCG affect fetal size has to be investigated in prospective studies. • Fetal volume measured by 3D volumetry in mares is relatively variable at day 45 ± 1 of gestation. • Early fetal volume is related to fetal sex, eCG and P4. • Sex specific growth differences exist already during early gestation in mares. • Early gestational fetal volume is unsuitable to predict birth weight or gestational length. [ABSTRACT FROM AUTHOR]

We aimed to evaluate the morphological ovarian response to equine chorionic gonadotropin (eCG) prior to ovum pick-up (OPU) and its effects on the molecular phenotype of immature cumulus-oocyte complexes (COCs) from Nelore cow (Bos indicus) donors. To this end, 20 Nelore cows were distributed randomly into the synchronized-OPU (Sync-OPU) and synchronized plus stimulated-OPU (Sync + eCG-OPU) groups using a cross-over experimental design, as each cow was used in both treatments. On a random day of the estrus cycle (Day 0), all cows received an intravaginal implant with 1.0 g of progesterone and 2 mg IM of estradiol benzoate. On the morning of Day 3, only the Sync + eCG-OPU group received 400 IU of eCG IM. On the morning of Day 5, the P4 device was removed and OPU was conducted in both groups. Before OPU management, ultrasonography was used to identify and measure the follicles. The aspirated COCs were morphologically classified based on their cumulus cells (CC) layers and the texture of the ooplasm. The COCs classified as Grade 1, Grade 2, and Grade 3 were considered viable and used for the assessment of quality markers. Oocytes and CC were mechanically separated from pools of 25 immature COCs of the Sync-OPU and Sync + eCG-OPU groups immediately after the follicular aspiration and stored at −80 °C until RNA extraction. Relative quantification of several markers for oocyte quality was assessed by RT-qPCR. The eCG treatment increased the number of follicles sized 3.0–5.0 mm and >5.0 mm compared to that in Sync-OPU group. Moreover, the protocol with eCG improved the total number of oocytes and the number of viable oocytes, which is related to a high number of oocytes in Grade 3. Regarding the impact on transcriptional regulation in immature oocytes, the mRNA encoding BMP15 , SMAD1 , SMAD2 , SMAD3 , ACACA , and CPT1A was upregulated in Sync + eCG-OPU compared with the Sync-OPU group. Moreover, the relative mRNA abundance of CTSZ , a member of the cathepsins family functionally related to reduced oocyte competence, was lower in the Sync + eCG-OPU group than in the Sync-OPU group. In addition, CC CTSB , CTSS , and CTSK mRNA abundances were lower in the Sync + eCG-OPU group than in the Sync-OPU group. However, the relative abundance of AREG and EREG mRNA was higher in CC recovered from cows stimulated with eCG. In conclusion, the eCG approach addressing follicular stimulation in Nelore cows had a positive impact on early antral follicle development, followed by a positive morphological and molecular phenotype in bovine COCs. • Ovarian response to equine chorionic gonadotropin (eCG) before ovum pick-up (OPU). • ECG before OPU increased number of follicles between 3.0 and 5.0 and > 5.0 mm. • ECG before OPU increased total number of oocytes and viable oocytes. • ECG before OPU modulated mRNA abundance of several genes related to oocyte quality. [ABSTRACT FROM AUTHOR]

Gonadotropins play vital roles in the regulation of female reproductive ability and fertility. Our study aimed to determine the effects of superovulation induced by increasing doses of equine chorionic gonadotropin [eCG; also referred to as pregnant mare serum gonadotropin (PMSG)] on the developmental competence of mouse embryos and on aneuploidy formation during in vitro fertilization (IVF). eCG dose-dependently enhanced the oocyte yield from each mouse. Administration of 15 IU eCG significantly reduced the fertilization rate and the formation of four-cell embryos and blastocysts and increased the risk of chromosome aneuploidy. The IVF-derived blastocysts in the 15 IU eCG treatment group had the fewest total cells, inner cell mass (ICM) cells and trophectoderm (TE) cells. Moreover, more blastocysts and fewer apoptotic cells were observed in the 0, 5, and 10 IU eCG treatment groups than in the 15 IU eCG treatment group. We also investigated reactive oxygen species (ROS) levels and variations in several variables: mitochondrial membrane potential (MMP); active mitochondria; mitochondrial superoxide production; adenosine triphosphate (ATP) content; spindle structures; chromosome karyotypes; microfilament distribution; and the expression of Aurora B [an important component of the chromosomal passenger complex (CPC)], the spindle assembly checkpoint (SAC) protein mitotic arrest deficient 2 like 1 (MAD2L1), and the DNA damage response (DDR) protein γH2AX. Injection of 15 IU eCG increased ROS levels, rapidly reduced MMP, increased active mitochondria numbers and mitochondrial superoxide production, reduced ATP content, increased abnormal spindle formation rates, and induced abnormalities in chromosome number and microfilament distribution, suggesting that a high dose of eCG might alter developmental competence and exert negative effects on IVF-obtained mouse embryos. Additionally, the appearance of γH2AX and the significantly increased expression of Aurora B and MAD2L1 suggested that administration of relatively high doses of eCG caused Aurora B-mediated SAC activation triggered by ROS-induced DNA damage in early mouse IVF-derived embryos for self-correction of aneuploidy formation. These findings improve our understanding of the application of gonadotropins and provide a theoretical basis for gonadotropin treatment.

Severe immunodeficient mice are an essential tool for the examination of the efficacy and safety of new therapeutic technologies as a humanized model. Previously, non-obese diabetic (NOD)/Shi-scid IL2rγ null (NOG) mice were established as immunodeficient mice by combining interleukin-2 receptor-γ chain-knockout mice and NOD/Shi-scid mice. The NOG mice are used frequently in the research of therapeutic monoclonal antibodies and regenerative medicine for human diseases. Establishment of an efficient production system of NOG mice, using optimized reproductive techniques, is required to accelerate research. In this study, we investigated the efficacy of the superovulation technique using equine chorionic gonadotropin (eCG) and inhibin antiserum (IAS) in NOG mice of various ages (4, 8, 12, 24, or 54 weeks). Additionally, we examined the fertilizing and developmental ability of the oocytes through in-vitro fertilization using frozen–thawed sperm, embryo culture and embryo transfer. The results showed that NOG mice produced the highest number of oocytes at 12 weeks old following the co-administration of eCG and IAS (collectively IASe) (70 oocytes/female). IASe was more effective in increasing the number of oocytes v. eCG at all ages. The IASe-derived oocytes demonstrated the ability to fertilize and develop into blastocysts and pups. Finally, we demonstrated that three strains of genetically modified NOG mice were efficiently produced through the optimized reproductive techniques. In summary, we developed an efficient system for the production of immunodeficient mice using 12-week-old, IASe-treated female NOG mice. [ABSTRACT FROM AUTHOR]

The Tsushima leopard cat (Prionailurus bengalensis euptilurus) is an endangered wild felid that lives solely on Tsushima Island, Nagasaki, Japan. Japan’s Ministry of the Environment is working with the Japanese Association of Zoo and Aquariums for ex situ conservation of this species. However, considering genetic diversity, it is difficult to conduct captive breeding programs by natural breeding alone; hence, assisted reproductive technologies are required. This study aimed to breed Tsushima leopard cats, which otherwise cannot be paired, using laparoscopic oviductal artificial insemination (AI). Female Tsushima leopard cats (female 1, aged 7 years; female 2, aged 6 years) were treated with 200 IU equine chorionic gonadotropin, followed by administration of 1000 IU porcine luteinizing hormone (pLH) after 96 h to induce ovulation. Laparoscopic AI was performed 32 h post-pLH administration. Females 1 and 2 were inseminated in the oviduct with 2.4 × 10⁶ and 3.3 × 10⁶ motile spermatozoa, respectively, collected from two males. Pregnancy was confirmed by radiography 45 and 51 days post-AI in females 1 and 2, respectively; one fetus was found in female 2. Moreover, female 2 had spontaneous delivery of a female kitten 66 days post-AI. This is the first successful case of AI in a Tsushima leopard cat.

This study has been conducted for the purpose of investigating the effect of injection sexually adult Shami male goats with eCG serum outside the reproductive season on reproductive qualities. In the current study, 36 male goats aged 1.5-2 years have been divided into three months and by 12 animals per month, as well as the animals have been divided into three treatments of four replicates for each month separately. Whereas the first treatment was T1 control without injection and the second and third treatments T2 and T3 in which males were injected with 250 and 500 IU of eCG hormone respectively. The injection was done at the beginning, middle and end of each month after the injection and semen was collected. As a result, the injection process resulted in a highly significant increase in individual and collective movement and sperm concentrations in Shami goats in Iraq as well as a highly significant increase in sperm abnormalities. Therefore, an inject of eCG hormone in Shami male goats outside the reproductive season recommended to stimulate them sexually. Where a highly significant effect of injection appears at rang (p < 0.05) on the individual movement of sperm whereas treatment at a dose of 500 and 250 exceeded the control treatment (90.43, 87.75 and 76.25), respectively. The current study also reveals a highly significant effect of injection appears on the collective movement of sperm. As well, treatments at a dose of 500 IU and 250 IU outperformed the control treatment (89.75, 88.25 and 77.50) respectively. A highly significant effect of injection appears sperm concentrations while treatment of injection at a dose of 500 exceeded the treatment of injection at a dose of 250 as well as control treatment. Where the 500 injection treatment outweighed the 250 injection treatment and control (3.60, 2.80 and 1.35) × 109 respectively and the 250 treatment outperformed the control treatment. Although, live sperm ratio at 500 IU injections exceeded 250 IU injections and control (91.75, 88.67 and 78.33), respectively, and 250 IU treatment outperformed the control. A highly significant effect appears in dead sperm ratio where treatment with a dose of 500 IU exceeded the treatment of 250 IU and control, and treatment of 250 IU outperformed control (8.25, 11.3 and 21.67), respectively. A highly significant effect also found on the deformed sperm ratio. [ABSTRACT FROM AUTHOR]

Various pharmaceutical products have been derived from horse blood and urine for over a century. Production of biologics and therapeutics from these samples is a niche industry and often occurs in regions with little regulation or veterinary oversight. To ensure good welfare of horses maintained for these purposes, guidance has been developed to support the industry.

In the Pelibuey breed, the dose of equine chorionic gonadotropin (eCG) used in the estrous synchronization is not fully established. The objective of this study was to analyze the effect of two different doses of eCG included in progestagens-based estrous synchronization protocols, on the reproductive response of Pelibuey ewes. For this reason, 28 and 24 ewes during two consecutive years were submitted to a synchronization protocol. The first group (LOW) considered the use of a CIDR for a 7-day period, followed by an i.m. administration of 0.125 mg of Cloprostenol and a dose of 300 U of eCG. The second group (HIGH) received the same protocol with a modification, the use of a 400 U of eCG. To evaluate the response variables, Fisher exact test and analysis of variance, were considered. There was no difference (P>0.05) between groups for the percentage of estrous ewes (92.31%), total conception rate (82.69%) and the conception rate of ewes with synchronized estrous (87.5%). Additionally, the estrous beginning (47.75±1.43 h) and prolificacy (1.86 lambs/partum) was similar between groups. In conclusion, the estrous synchronization protocols for Pelibuey ewes using CIDR for a 7-day period, can use eCG in a dose of 300 U without effects on their associated reproductive performance. [ABSTRACT FROM AUTHOR]

This study was conducted to investigate the different doses of eCG on reproductive performance activities in Lake and Torki Ghashghaei ewes in spring season. In this study 75 Lake Ghashghaei ewes and Torki Ghashghaei ewes (3 to 4 years old) with the mean weight of 55±1.8 and 58±2.2 kgs were chosen respectively and divided into 5 treatment groups. The estrus cycle of the ewes were synchronized with progesterone sponges during a 14 days period. In each race one day before removing the sponges 300, 400, 500 and 600 eCG IU were injected intramuscularly to group 2 to 5 respectively and group one was assumed as control. The results showed that all of Lake Ghashghaei ewes in group three and four and Torki Ghashghaei ewes in group three, four and five showed estrus signs, after 48 h of removing sponges. There were not any significant differences (P>0.05) among different treatment groups in the percentage of pregnant ewes. In both races the groups which received eCG had more percentage of twining rate compared with control and the number of ewes with twin lambs increased after increasing the dose of eCG. In conclusion the results showed that in Lake and Torki Ghashghaei 400 and 500 eCG IU had the most effect on pregnancy and twining rate in spring season respectively. [ABSTRACT FROM AUTHOR]

In order to investigate the different times of GnRH injection on the reproductive activities of Lake-Ghashghaei ewes supperovulated with eCG in autumn season, 60 ewes (2-3 ages and average body weight 49±1.8 Kg) were chosen. Estrus cycle of ewes were synchronized by progesterone sponges during a 14 days period. One day before removing the sponges, 400 IU of eCG were injected intramuscularly. Then the ewes were divided into 4 groups according to receiving GnRH on different days (one, seven and 12 days) or not receiving GnRH (control) after estrus observation and reproductive indexes such as the rate of return to estrus and pregnancy rate, were measured and compared among different groups in two continuous estrus cycle. The result indicated that there were not any significant differences (P>0.05) in the rate of return to estrus, pregnancy rate, parturation rate, fecundity and prolificacy among treatment groups, but the rate of twin birth was significantly (P<0.05) lesser in the groups, receiving GnRH in 7 and 12 days compared with the group that recieved GnRH in the first day. Serum progesterone concentration in pregnant, delivered, single and twin births ewes that received GnRH were significantly (P<0.05) more than control ewes. In conclusion, GnRH administration during different days after mating increased serum progesterone concentration in Lake-Ghashghaei ewes. Moreover, the rate of twining birth in ewes which received GnRH on the first day, was significantly more compared with using GnRH on 7th and 12th days after estrus. [ABSTRACT FROM AUTHOR]

The aim of this study was to investigate the effect of progesterone (P4)-based timed artificial insemination (TAI) programs on fertility in seasonal-calving, pasture-based dairy herds. A total of 1,421 lactating dairy cows on 4 spring-calving farms were stratified based on days in milk (DIM) and parity and randomly allocated to 1 of 3 treatments: (1) control: no hormonal treatment; cows inseminated at detected estrus; (2) P4- Ovsynch: cows received a 7-d P4-releasing intravaginal device (PRID Delta; CEVA Santé Animale, Libourne, France) with 100 µg of a gonadotropin-releasing hormone (GnRH) analog (Ovarelin; CEVA Santé Animale) at PRID insertion, a 25-mg injection of PGF2a (Enzaprost; CEVA Santé Animale) at PRID removal, GnRH at 56 h after device removal and TAI 16 h later; (3) P4-Ovsynch+eCG: the same as P4-Ovsynch, but cows received 500 IU of equine chorionic gonadotropin (eCG; Syncrostim; CEVA Santé Animale) at PRID removal. At 10 d before mating start date (MSD), all cows that were =35 DIM were examined by transrectal ultrasound to assess presence or absence of a corpus luteum; body condition score (BCS) was also recorded. Pregnancy diagnosis was performed by transrectal ultrasonography 30 to 35 d after insemination. Overall pregnancy/AI (P/AI) was not different between groups (50.9, 49.8, and 46.3% for control, P4-Ovsynch, and P4-Ovsynch+eCG, respectively) but the 21-d pregnancy rate was increased by the use of synchronization (35.0, 51.7, and 47.2%, respectively). Compared with the control group, synchronization significantly reduced the interval from MSD to conception (34.6, 23.0, and 26.5 d, respectively) and consequently reduced the average days open (98.0, 86.0, and 89.0 d). Across all treatment groups, DIM at the start of synchronization affected P/AI (42.3, 49.5, and 53.9% for <60, 60-80, and >80 DIM, respectively), but neither parity (46.5, 50.4, and 48.4% for parity 1, 2, and =3, respectively) nor BCS (44.0, 49.4, and 58.6% for =2.50, 2.75-3.25, and =3.50, respectively) affected the likelihood of P/AI. Two-way interactions between treatment and DIM, parity, or BCS were not detected. In conclusion, the use of TAI accelerated pregnancy establishment in cows in a pasture-based system by reducing days open, but eCG administration at PRID removal did not affect P/AI. [ABSTRACT FROM AUTHOR]

The objective of this study was to evaluate the effect of equine chorionic gonadotropin (eCG) on the estrous response, ovulatory follicle development, ovulation rate, corpus luteum (CL) diameter, concentrations of progesterone (P4) and pregnancy per AI (P/AI) in CIDR-EB treated lactating anovular Nili-Ravi buffalo during the breeding season. Buffalo ( n = 87), 60 to 200 Days postpartum were treated with CIDR at a random stage of the estrous cycle (Day 0) and assigned to two groups; with eCG (+eCG; n  = 44), or without eCG (-eCG; n  = 43). In both groups, each animal received 2 and 1 mg estradiol benzoate (EB) on Day 0 and then on Day 8, respectively. On Day 6, eCG and PGF 2α were administered. On Day 7, CIDR were removed and FTAI was performed at 48 and 60 h later and pregnancy was diagnosed 35 Days post AI. The results revealed that eCG treatment increased ( P  <  0.05) the CL diameter on 15, 18, and 21 after the ovulation that resulted from imposing the estrous synchronization protocol than when eCG was not administered. Similarly, treatment with eCG resulted in an increased ( P  <  0.05) mean concentration of P4 as compared with animals not treated with eCG on Days 18 and 21 after the ovulation that occurred subsequent to imposing the estrous synchronization protocol. The ovulation rate was greater in eCG-treated buffalo as compared with those not treated with eCG (93% compared with 74%, respectively; P < 0.05). The P/AI was greater in buffalo treated with eCG than those not treated with eCG (56% compared with 31%, respectively; P < 0.05). In conclusion, the addition of eCG along with EB and P4 based treatments enhanced the estrous response, follicular and luteal function, ovulation rate, concentrations of P4, and P/AI in lactating anovular Nili-Ravi buffalo. [ABSTRACT FROM AUTHOR]

The aim of this study was to investigate the efficacy of equine chorionic gonadotropin (eCG) and cloprostenol (CLO) administration on oestrus synchronisation, uterine development as well as serum LH and FSH concentrations in mice. One hundred and five KM mice were assigned into eCG-1, eCG-2, eCG-3, CLO-1, CLO-2, CLO-3 and control groups (CG, n = 15). The eCG-1, eCG-2 and eCG-3 groups were intramuscularly injected with 10, 20 and 40 IU eCG. CLO-1, CLO-2 and CLO-3 were intramuscularly injected with 10, 15 and 20 μg cloprostenol acetate. The results showed that 93.33% and 66.67% of synchronised mice displayed oestrus within 18.68-37.59 h. Oestrus numbers, oestrus onset time (EOT) and oestrus rate in CLO and eCG groups were greater than in CG (P < 0.05). EOT in CLO and eCG groups were 19.88 ± 2.91 h and 34.84 ± 5.05 h. Uterine weights of treatment groups were larger than CG. Uterine weights of the eCG group were higher than those in the CLO group. Uterine horn longitudial diameters (ULD) in treatment groups were larger than CG during the experiment. ULD in eCG-2 and eCG-3 were significantly greater when compared to CG (P < 0.05 or P < 0.01). On days 14 and 21, uterine horn transverse diameters (UTD) in CLO-1, eCG-1, eCG-2 and eCG-3 subgroups were significantly larger than that of CG (P < 0.05 or P < 0.01). Serum LH concentrations in eCG and CLO increased. Increments in eCG and CLO groups were greater than that of CG. FSH concentrations in eCG mice were higher than those in CLO and CG mice (P < 0.05) on day 21. Thus, eCG and cloprostenol treatments in mice can improve uterine development and promote the secretion of LH and FSH.

Conventional practice is to breed sows by artificial insemination (AI) at least twice using approximately three billion sperm per insemination upon estrus at standing heat. This research explored the use of combined technologies, including fixed-time insemination (FTAI) and an alternative catheter design that reportedly reduces semen backflow, in order to reduce the number of inseminations and the semen dosage and maintain reproductive efficiency. The FTAI technique used in this study was to inject I.M. 600 IU equine chorionic gonadotropin (eCG) at weaning and 5 mg porcine luteinizing hormone (pLH) to stimulate ovulation 80 h later, followed by a single insemination 36 h after the pLH injection. The two catheters used in this study were a conventional foam-tipped insemination catheter and a Gedis catheter. The Gedis catheter is designed to be completely inserted into the vagina. The semen is enclosed along the length of the rod and held in place by a gel cap that melts when inserted into the cervix. Sows were assigned to the following treatments: Group 1 (n = 135), bred twice with a conventional catheter and a standard semen dose of approximately three billion sperm in 80 mL; Group 2 (n = 123), FTAI with conventional catheter and a standard semen dose; Group 3 (n = 127), FTAI with Gedis catheter and a standard semen dose; Group 4 (n = 126), FTAI with Gedis catheter and a reduced semen dose with one billion sperm. The farrowing rates were 81.6%, 77.7%, 74.0%, and 62.7% for Groups 1 to 4, respectively. The likelihood of farrowing was lower for Group 3 and Group 4 compared to Group 1 (odds ratio (OR) = 0.57; p = 0.08 and OR = 0.35; p = 0.001, respectively). Likewise, litter size of Group 3 and Group 4 was smaller than Group 1 (p = 0.006 and p = 0.04, respectively). Overall, the combination of Gedis catheter and FTAI resulted in decreased reproductive performance that outweighed the value of using less semen.

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The objective of this study was to compare synchronization protocols with one and two applications of a luteolytic, simultaneous or not, to equine chorionic gonadotrophin (eCG) on the diameter of the ovulatory follicle (DFOL) and the conception rate of cyclic dairy crossbred females. For this, on D0 the protocol was initiated by means of insertion of progesterone device (P4) and application of 2.0mg of estradiol benzoate. In D7 they received 12.5mg of dinoprost tromethamine. In D9 performed removal of P4 and applied 0.6mg of estradiol cypionate. At this time, females were subdivided into the following treatments: Control Group - 2.5mL of saline solution, Group 2PGF - 12.5mg of dinoprost tromethamine, eCG, Group eCG - 300UI eCG, Group 2PGF + eCG - 300UI eCG and 12.5mg of dinoprost tromethamine. In D11 transrectal ultrasonography (US) was performed to determine the DFOL and the animals were inseminated. The diagnosis of gestation was performed for 55 days after. The obtained data were evaluated by the SPSS considering P=0.05. The DFOL and conception rate were similar between synchronization protocols. It was concluded that in cyclic animals the use of protocol with a single PGF2a dose and without gonadotropic support of eCG seems to provide adequate follicular response and satisfactory fertility indexes. [ABSTRACT FROM AUTHOR]

Contents Recently, it has been demonstrated that administration of equine chorionic gonadotropin ( eCG) in the postpartum period in dairy cows can enhance follicle growth, reduce the interval from calving to first ovulation and increase plasma estradiol concentrations, and, thus, could enhance reproductive performance in a dairy herd when administered on day 6 postpartum. The aim of this study was to investigate the effects of a single dose of eCG between days 9 and 15 postpartum on parameters of reproductive performance in dairy cows. German Holstein cows ( n = 1937; primiparous cows: n = 748; pluriparous cows: n = 1189) in a commercial dairy farm were randomly assigned to three experimental groups. Animals within the group eCG received a single dose of 600 IU eCG intramuscularly (i.m.) between days 9 and 15 postpartum followed by an i.m. administration of 500 μg cloprostenol after 14 days. Those of treatment group PG received cloprostenol only between days 23 and 29 postpartum. Cows of the control group remained untreated. Starting on day 49 postpartum, cows were subjected to a Presynch-Ovsynch protocol and inseminated artificially. The impact of application time (days postpartum) of eCG on the intervals calving to first service and calving to conception was statistically not significant. Outcomes of reproductive performance (i.e. first service conception rate, proportion of pregnant cows until 100 and 150 days in milk [ DIM], number of inseminations until 150 DIM, calving to first service interval and calving to conception interval) did not differ significantly between treatment group eCG and group PG compared to control group. Regarding postpartum eCG administration, significant interactions between treatment and parity, season, milk yield, and early puerperal disorders, respectively, could not be shown. In conclusion, an eCG treatment of dairy cows between days 9 and 15 postpartum to increase reproductive performance cannot be recommended under the given circumstances. [ABSTRACT FROM AUTHOR]

This study aims to investigate the estrus efficacy of FIS (fluorogestone intravaginal sponges)/eCG (equine chorionic gonadotropin) and cloprostenol treatments to establish the optimum protocols for estrus synchronization in ewes. Forty-two ewes were assigned into groups A (FIS/eCG group) and B (CLO (cloprostenol) group). Each group was randomly divided into three subgroups (n = 7) according to the dose of eCG (ECG1, ECG2 and ECG3) or cloprostenol (CLO1, CLO2 and CLO3). The estrus rates, lambing rates and average litter sizes were accounted. Serum concentrations of progesterone (P4), follicle-stimulating hormone (FSH) and luteinizing hormone were determined. Selected optimum schemes were employed in 636 ewes in four sheep farms. Estrus rates of groups A and B were 85.72% and 57.14%. Estrus onset times (EOTs) were 53.91 ± 12.26 and 46.41 ± 4.65 h for groups A and B. EOT of ECG1 was longer than that of CLO3 (P < .05). Lamb numbers, lambing rate and litter size of group B were lower than those of group A. The maximum and minimum lambing rates were calculated in ECG3 and CLO1 (157 vs. 57). On day 11, higher P4 values (P < .05) were determined of ECG3 and CLO1 compared to CLO2 and CLO3 subgroups. FSH concentration of ECG1 was significantly higher than that in group B (P < .05). Application results showed that estrus rate, pregnancy rate and lambing rates of ECG3 and CLO3 protocols were 95.97% vs. 70.91%, 91.37% vs. 88.89% and 149.87% vs 132.69% (P < .05), respectively. FIS/eCG and cloprostenol improved estrus synchronization. Injection of 400 IU eCG after FIS withdrawal was an optimum protocol for estrus synchronization of ewes. [ABSTRACT FROM PUBLISHER]

Ovarian stimulation with commercial preparations of equine chorionic gonadotropin (eCG) produces extremely variable responses in domestic animals, ranging from excessive stimulation to practically no stimulation, when applied on the basis of their declared unitage. This study was conducted to analyze four commercial preparations from different manufacturers via reversed-phase HPLC (RP-HPLC) in comparison with a reference preparation and an official International Standard from the World Health Organization. The peaks obtained by this qualitative and quantitative physical-chemical analysis were compared using an in vivo bioassay based on the ovarian weight gain of prepubertal female rats. The RP-HPLC data showed one or two peaks close to a main peak (tR = 27.9 min), which were related to the in vivo bioactivity. Commercial preparations that have this altered peak showed very little or no in vivo activity, as demonstrated by rat ovarian weight and in peripubertal gilts induced to ovulate. Overall, these findings indicate that RP-HPLC can be a rapid and reliable tool to reveal changes in the physicochemical profile of commercial eCG that is apparently related to decreased biological activity of this hormone. [ABSTRACT FROM AUTHOR]