GnRH analogue triptorelin acetate induces ovulation in jennies during oestrus.

Most of the northern hemisphere donkey breeds are faced with the risk of extinction, thus donkey reproduction is considered an emerging branch of theriogenology, and the management of artificial insemination and induction of ovulation is a crucial point in setting up preservation protocols. For four consecutive cycles, six jennies' ovarian activity was routinely monitored; an ultrasound examination was performed daily from the evidence of a follicle diameter ≥27 mm until ovulation. Upon reaching a follicular diameter ≥32 ± 2 mm (Hour 0), oestrous jennies were treated alternatively with 0.1 mg triptorelin acetate, sc, (TRIP), 0.4 mg/sc of buserelin acetate (BUS) or saline, sc, (CTRL) and examined ultrasonographically at Hours 14, 24, 38, 42, 48, 62 and every 24 h until ovulation. Induction of ovulation was considered successful if ovulation occurred from 24 to 48 h after treatment. 11/12 cycles resulted in ovulation for TRIP and 12/12 for BUS and CTRL groups, respectively. Mean ± SD ovulation time after treatment was 37.3 ± 8.3, 47.1 ± 21.0 and 66.8 ± 25.9 h for BUS, TRIP and CTRL, respectively (p = .0032). Ovulation rates between h24 and h48 were 10/12 (83.3%) for both TRIP/BUS and 2/12 (16.7%) for CTRL, respectively (p = .003). Buserelin and triptorelin-treated jennies had a 25 times higher probability to ovulate between Hours 24 and 48 than controls (p = .003), while there were no jenny and cycle effects on the ovulatory rate. The results of this study show how triptorelin successfully induced ovulation in jennies, like other GnRH analogues previously evaluated.

Serum anti-Müllerian hormone around the time of ovulation simulated by exogenous hormones in clouded leopards (Neofelis nebulosa).

Anti-Müllerian hormone (AMH) is produced by granulosa cells of the antral follicles. It serves as a promising biomarker for ovarian reserve and responsiveness to ovarian stimulation in humans and domestic animals. This study aimed to validate the AMH Gen II enzyme-linked immunosorbent assay (ELISA) and correlate ovarian structures with serum AMH concentrations after stimulation treatment in clouded leopards (Neofelis nebulosa). Serum samples were collected from 12 women (age 6.21 ± 3.56 years), and serum AMH concentrations were analysed using AMH Gen II ELISA. The animals were divided into two groups based on ovarian structures [preovulatory follicles (>2 mm) and/or corpora hemorrhagica] along with the presence of uterine tonicity visualized laparoscopically around the time of ovulation. Animals that exhibited these reproductive features were identified as the responder group (n = 9, aged 7.59 ± 2.96 years), whereas those lacking the corresponding features were assigned to the nonresponder group (n = 3, aged 2.06 ± 0.53 years). The intra-assay coefficient of variation (CV) and interassay CV was 3.56% and 7.75%, respectively. The linearity of AMH dilution was confirmed (r2 = .998), and the percentage of recovery ranged from 93% to 115%. The results demonstrated that overall serum AMH concentrations around the time of ovulation were negatively correlated with age (rs = -.692, p = .013). However, serum AMH concentrations were not correlated with the average number of ovarian structures (rs = -.535, p = .074). Thus, AMH Gen II ELISA was validated in clouded leopards. Around the time of ovulation, serum AMH decreased with advancing age and ovarian responsiveness cannot be evaluated using serum AMH.

The effect of different FSH administration before ovum pick up on superstimulation response and oocyte yield.

This study aims to evaluate the effect of synchronization and different superstimulation protocols on oocyte yield before ovum-pick up (OPU) to provide a homogeneous follicle population. Animals in all study groups except the control group applied a synchronization protocol including modified ovsynch+progesterone and dominant follicle ablation (DFA, on the 6th day following synchronization). In group 1, oocytes were retrieved by ultrasonography only on the 4th day after DFA. In group 2, 250 µg pFSH (100 µg IM, 150 µg SC) was administered as a single dose on the 2nd day following DFA, and oocytes were retrieved on the 2nd day following this injection. In group 3, 250 µg pFSH was administered IM in four equal doses 12 h apart on the 1st and 2nd days following DFA, and oocytes were retrieved 2 days after the last FSH injection. In group 4, 250 µg pFSH (IM) dissolved in Montanide ISA 206 adjuvant was administered as a single dose on the 2nd day following DFA, and oocytes were retrieved 2 days after this treatment. In the control group (group 5), oocytes were retrieved from animals without any hormonal treatment on a random day of the oestrus cycle. In order to assess the follicle population in the ovary on the day of OPU, the number of follicles according to their diameter was determined by ultrasonography in all groups. The ratio of medium-sized follicles (3-8 mm) was higher in the synchronized groups (Groups 1, 2, 3 and 4) than in the control group (Group 5) (p < .05). It was determined that the total number of oocytes obtained after OPU and the number of oocytes of suitable quality (Grade A and B) in in vitro embryo production were higher in the superstimulated groups (Groups 2, 3 and 4) compared to the control group. It was found that the number of Grade-A quality oocytes was higher in the superstimulated groups (Groups 2, 3 and 4) than the other groups. As a result, it was found that the synchronization and superstimulation treatments prior to the OPU increased the ratio of medium-sized follicles and the total number of oocytes obtained. In addition to the synchronization protocol, it was determined that superstimulation treatments increased the oocyte quality obtained with OPU. Furthermore, it was observed that a single dose of FSH dissolved in Montanide ISA 206 adjuvant produced a superstimulation response similar to that produced by repeated doses of FSH.

Success of embryo transfer of hybrid embryos in Old World camelids: A first study.

This is the first study to test the embryo transfer (ET) of hybrid embryos in Old World camelids and produces a live calf from a dromedary recipient. Hybrid embryos were collected from 7 dromedary and 10 Bactrian donors, with or without ovarian super-stimulation, and transferred to dromedary recipients. Pregnancy diagnosis was conducted on Day 10 post-ET by using the progesterone-ELISA test and trans-rectal ultrasonography at 1 and 2 months of gestation. The date of abortion, stillbirth, or normal calving for each pregnant recipient was recorded. Without ovarian super-stimulation, two and one recipients were pregnant at 10 days post-ET, from ♂ Bactrian X ♀ dromedary and ♂ dromedary X ♀ Bactrian, respectively. While at 2 months of gestation, only one recipient was diagnosed pregnant from ♂ Bactrian X ♀ dromedary. Response to ovarian super-stimulation was successful in all 4 of the tested dromedary donors and in 8 out of 10 Bactrian donors. Additionally, 4 super-stimulated Bactrian donors (40%) showed failure of ovulation. The number of super-stimulated developed follicles and recovered embryos was higher in dromedary donors compared to Bactrian donors. Ten and two recipients were diagnosed pregnant at 10 days post-ET for ♂ Bactrian X ♀ dromedary and ♂ dromedary X ♀ Bactrian, respectively. At 2 months of gestation, the number of pregnant recipients from ♂ Bactrian X ♀ dromedary was reduced to eight, while the two pregnant recipients from ♂ dromedary X ♀ Bactrian remained pregnant. Total early pregnancy loss at 2 months gestation for all transferred hybrid embryos, obtained with or without ovarian super-stimulation, was 4/15 (26.6%). One healthy male calf was born from a recipient, with a total gestation period of 383 days, that received an embryo from a Bactrian male and a dromedary donor. Stillbirth was observed in six cases after 10.5-12 months of gestation and three cases aborted between 7 and 9 months of gestation due to trypanosomiasis. In conclusion, ET of hybrid embryos in Old World camelids is successful. However, further studies are required to improve the outcome of this technology to be used for meat and milk production in camels.

The post-ovulatory rise in progesterone is lower and the persistence of oestrous behaviour longer during the first compared with the second cycle of the breeding season in mares.

Mares are seasonally polyoestrous breeders. Therefore, the first ovulation of the season, following winter anoestrus, is the only cycle in which mares ovulate without the presence of an old CL from the previous cycle. The objective of this study was to compare the length of oestrous behaviour, and plasma progesterone concentrations during the early post-ovulatory period between mares after the first and second ovulation of the breeding season. Overall, 38 mares and 167 oestrous periods were used in the study. From those, 11 mares were used during the first and subsequent oestrous period to measure and compare the post-ovulatory rise in progesterone concentration, whereas all the mares were used to compare the length of the post-ovulatory oestrous behaviour between the first and subsequent cycles of the breeding season. The persistence of the post-ovulatory oestrus was longer (p < .001) following the first ovulation of the year (median of 52 h) compared with the subsequent ovulations (median of 36 h for second and later ovulations groups; n = 38 mares). The progesterone concentration at any of the four 8 h-intervals analysed (28, 36, 76 and 84 h post-ovulation) was lower (p < .01) following the first versus the second ovulation of the year. By 36 h post-ovulation the progesterone concentration of mares at the second ovulation of the year had passed the threshold of 2 ng/ml (2.1 ± 0.33 ng/ml), whereas in the first cycle it was 1.2 ± 0.13 ng/ml. In conclusion, mares had lower progesterone concentrations in their peripheral circulation and longer persistence of oestrous behaviour following the first ovulation of the year compared with the second and subsequent ovulatory periods of the breeding season.

Effect of follicular ablation and gonadotropin priming on the recovery and quality of oocytes in Boran cows.

The objective of the study was to evaluate the effect of follicle ablation, exogenous FSH application, and different coasting time prior to ovum pick-up (OPU) on the number of follicles suitable for aspiration, oocyte quality, and cleavage rate in Ethiopian Boran cows. The experiment was carried out in three parts, (I) cows were synchronized using 500 µg PGF2α given 11 days apart. Cows were then subjected to a biweekly ovum pickup session before ovulation (n = 5) or starting day 7 after ovulation (n = 4) for 3 weeks. (II) Cows were synchronized, and all visible follicles were ablated on the first days of overt estrus, and cows were grouped into those that received a divided dose of 350 IU FSH (n = 5) or 175 IU FSH (n = 5) over 3 days. In both groups, OPU was carried out weekly starting 48 h after the last FSH for 6 weeks. (III) Protocol was similar to part II, but in group with 350 IU FSH (n = 5), coasting period was increased to 72 h. The covariates of follicles and oocyte were not affected (P > 0.05) by corpus luteum presence at OPU. The mean number of medium (7.36 ± 0.57) and large (8.28 ± 0.96) follicles were significantly higher (P < 0.05) in the group that received divided 350 IU FSH. Similarly, the mean number of grade-1 (4.19 ± 0.24) and grade-2 (4.32 ± .27) oocytes, maturation rate (70.41%), and cleavage rate (47.5%) were significantly higher (P < 0.05) in the group that received 350 IU FSH. COC quality was significantly (P < 0.05) influenced by coasting period. However, both maturation and cleavage rates were not affected by the coasting period. This study demonstrated that follicular ablation and treatment with FSH improves follicular population and oocyte recovery rate in Boran cows.

Artificial Insemination in Queens in the Clinical Practice Setting: Protocols and challenges.

PRACTICAL RELEVANCE: Despite substantial advances in assisted reproductive techniques having been recently reported in cats, the use of these is limited and routine application is still far from being a reality in veterinary clinics. Nevertheless, there is an increasing demand from domestic cat breeders for artificial insemination (AI) techniques that are already commonly used in dogs. Where natural breeding is not possible in tom cats and queens of high breeding value, AI could offer a solution. Clinical challenges: AI in cats is more difficult than in other species - both in terms of semen collection/handling and oestrous cycle management given that ovulation must be induced. AIM: For practitioners wishing to perform AI in queens, there are challenges to overcome, and a good understanding of the techniques and procedures involved is pivotal. This review aims to contribute to improved knowledge by providing an overview of AI protocols, encompassing choice of breeding animals, procedures for semen collection, oestrus and ovulation induction, AI techniques and equipment. EQUIPMENT AND TECHNICAL SKILLS: Depending on the animals involved and the specific AI technique chosen, essential equipment may include an artificial vagina, electroejaculator, endoscope (sialendoscope, which can be fairly expensive) and special catheters for transcervical insemination. Other instrumentation and materials needed are typically readily available in a veterinary clinic. In general, no particular skills are needed to perform the procedures described in this review, with the exception of endoscopic transcervical catheterisation, where the ability to use an endoscope is required. EVIDENCE BASE: The information and advice/recommendations provided are based on specific feline research and reviews published in scientific peer-reviewed journals, animal reproduction textbooks, and presentations at national and international congresses. The authors also drew on their own clinical experience with regard to the choice of protocols and procedures presented in this review.

The Kisspeptin analogue C6 induces ovulation in jennies.

Kisspeptins (KPs) are the most potent stimulating neurotransmitters of GnRH release, and consequently KP administration triggers LH and/or FSH release. In small ruminants, KP or its analogs induced an LH surge followed by ovulation in both cyclic and acyclic animals, while in the mare KP only increased LH plasma levels but failed to induce ovulation. This study in jennies compares the endocrinological effects, ovulatory and pregnancy rates of the KP analog C6 and the GnRH analog buserelin acetate. The ovarian activity of nine Amiata jennies was monitored daily by transrectal ultrasound for three complete estrous cycles. Jennies in estrus were assigned, to one of three treatment groups: 50 nmol of the KP analog C6 (injected twice, 24 h apart, C6 group); 0.4 mg buserelin acetate (injected once, Bu group); and 2 mL of saline (injected once, CTRL group). Blood samples were collected at Day-1 (-24 h) Day0 (h0, before treatment), h2, h4, h6, h8, h10, h24 (before second treatment with C6), h26, h28, h30, h32, h34, h48 and every 24 h until ovulation. Jennies were inseminated once at h24 with fresh extended semen from a donkey stallion. Pregnancy diagnoses were performed 14 days after ovulation. On days 5, 10, and 14 after ovulation, for every CL the cross-sectional area (CSA) and the vascularized area (VA) were recorded by color doppler ultrasound and measured. Significantly higher plasma LH levels were found after induction between the Bu and CTRL groups at h6 and h8 (P < 0.05), while tendentially higher differences were found between the Bu/C6 groups and CTRL at h10. Five/9, 4/9, and 2/9 jennies ovulated between 24 and 48 h after induction from the Bu, C6, and CTRL groups respectively, (P > 0.05). Correlations between corpora lutea CSA and VA with serum progesterone concentration were r = 0.31, P = 0.01, r = 0.38, P = 0.01, respectively. Pregnancy rates after artificial insemination did not differ among groups (CTRL: 6/9, 66.7%; C6: 7/9, 77.8%; Bu: 6/9, 66.7%; P > 0.05). Ovulation rates after C6 treatment were comparable to that of Bu, although not different from the CTRL. Pregnancy rates were comparable to the literature in terms of fresh extended donkey semen in every group. This study suggests that stimulation of the Kp system in jennies, in contrast to findings observed in mares, induces ovulation. Further studies using higher doses and/or more animals are needed to better characterize the efficacy of C6 in jennies.

A controlled ovarian stimulation procedure suitable for cynomolgus macaques.

This study aimed to develop a more suitable ovarian stimulation procedure for cynomolgus macaques (Macaca fascicularis). Macaques were divided into 4 groups, 7AG, 8AG, 7AN, and 8AN, according to the ovarian stimulation procedure administered (i.e., administration of either a gonadotropin-releasing hormone agonist [GnRH-a] or GnRH antagonist [GnRH-ant]) and the number of menstruations (≤ 7 times or ≥ 8 times) in the previous year. In both procedures, oocyte growth and maturation were induced by administration of human follicle-stimulating hormone and human chorionic gonadotropin. The mean numbers of metaphase II mature and metaphase I premature oocytes collected from the 7AG, 8AG, 7AN, and 8AN groups were 12.1 and 10.4, 12.0 and 13.8, 9.1 and 8.3, and 15.5 and 8.8, respectively (P>0.05). The fertilization rates of the 7AN and 8AN groups (85.3% and 74.7%) tended to be higher compared with those in the 7AG and 8AG groups (59.1% and 47.3%; P>0.05). The 8AN group yielded 19.9 zygotes, which was the largest number per macaque, compared with the other three groups. Furthermore, regarding the decreases in body weight between the start of the procedures and the time of oocyte collection, those of the 7AN and 8AN groups were significantly smaller than those of the 7AG and 8AG groups (P<0.05), suggesting that the procedure involving GnRH-ant reduced the burden on the macaques. Thus, controlled ovarian stimulation using a GnRH-ant has some advantages for cynomolgus macaques compared with that using a GnRH-a.

Excessive follicle-stimulating hormone during ovarian stimulation of cattle may induce premature luteinization of most ovulatory-size follicles†.

High follicle-stimulating hormone (FSH) doses during ovarian stimulation are detrimental to ovulatory follicle function and decrease live birth rate in cattle and women. However, the mechanism whereby excessive FSH causes ovarian dysfunction is unknown. This study tested the hypothesis that excessive FSH during ovarian stimulation induces premature luteinization of ovulatory-size follicles. Small ovarian reserve heifers were injected twice daily for 4 days with 70 IU (N = 7 heifers) or 210 IU (N = 6 heifers) Folltropin-V [commercial FSH-enriched preparation of porcine pituitary glands with minor (<1%) luteinizing hormone (LH) contamination, cpFSH]. Ovulatory-size (≥10 mm) follicles were excised from ovaries after the last cpFSH injection and hormone concentrations in follicular fluid (FF) were determined using ELISA. Luteinization was monitored by assessing cumulus cell-oocyte complex (COC) morphology and measuring concentrations of estradiol (E), progesterone (P), and oxytocin (O) in FF. COCs were classified as having compact (cCOC) or expanded (eCOC) cumulus cell layers, and as estrogen-active (E:P in FF ≥1), estrogen-inactive (EI, E:P in FF ≤1 > 0.1), or extreme-estrogen-inactive (EEI, E:P in FF ≤0.1). A high proportion (72%) of ovulatory-size follicles in 210 IU, but not 70 IU, dose heifers displayed eCOCs. The high doses also produced higher proportions of EI or EEI follicles which had lower E:P ratio and/or E but higher P and/or O concentrations compared with the 70 IU dose heifers. In conclusion, excessive cpFSH doses during ovarian stimulation may induce premature luteinization of most ovulatory-size follicles in heifers with small ovarian reserves.

hCG is more effective than the GnRH agonist buserelin for inducing the first ovulation of the breeding season in mares.

BACKGROUND: Human Chorionic Gonadotropin (hCG) and Gonadotropin Releasing Hormone agonists (GnRHa) are routinely used to induce ovulation in mares. However, GnRHa efficacy in transitional mares has been suggested to be low. OBJECTIVES: The aims of this study were as follows: (a) to compare the efficacy of hCG and GnRHa in inducing the first ovulation of the breeding season and (b) to evaluate the correlation between ovulatory response, uterine oedema and teasing score at the time of treatment during the early or late transitional phase. STUDY DESIGN: Randomised controlled superiority trial. METHODS: Mares in winter anoestrus were treated with sulpiride when at least two follicles reached a diameter of 25 mm. The day after the follicle reached 35 mm in diameter, mares in oestrus were treated with GnRHa buserelin (N = 29) or hCG (N = 33) and checked daily for ovulation. RESULTS: More mares (30/33, 90.1%) ovulated when the first ovulation after winter anoestrus was induced with hCG, than with GnRHa, (11/29, 38.0%) (P = .0001). Ovulation rate was lower in mares that did not show uterine oedema and full acceptance of the teaser stallion for at least three days before the treatment (32/41, 78% vs 9/21, 42.9%) P = .01. MAIN LIMITATIONS: Plasma LH and oestrogen concentrations were not performed. CONCLUSIONS: These results demonstrate that hCG was more effective than GnRHa for inducing ovulation in the first cycle after winter anoestrus. Uterine oedema and behavioural signs of oestrus, for at least three days before the treatment, were predictors for a positive response to ovulation induction.

The effect of fixed-time artificial insemination protocol initiated at different stages of the estrous cycle on follicle development and ovulation in gilts.

Hormonal products have been developed for fixed-time artificial insemination (FTAI) to improve the efficiency of swine production. Here, we evaluated the effect of an FTAI protocol initiated during different phases of the estrous cycle on follicle development and ovulation in gilts. A total of 36 gilts were equally divided into three groups designated as the luteal (L), follicular (F), and post-ovulation (O) groups and fed with 20 mg of altrenogest for 18 days, followed by intramuscular injection of 1000 IU PMSG at 42 h after withdrawal of altrenogest, and 100 µg of GnRH after an 80-h interval. The L group had the highest number of follicles 4-6 mm in diameter, as well as corpora hemorrhagica. The mRNA expression of caspase-9 in the L group were significantly lower than those in the O and F groups (P < 0.05), while CYP11A1 and VEGF mRNA expression levels were significantly higher (P < 0.05). Moreover, FSHR mRNA levels were significantly higher in the O group than in the L, F, and control groups (P < 0.05). LHCGR and CYP19A1 mRNA levels were the highest in the F group (P < 0.05). Thus, the changes in the expression of genes associated with follicular development, maturation, and ovulation identified in this study indicated that initiation of the FTAI protocol during the luteal phase induced a better environment for follicle development and ovulation in gilts.

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.

Vaginal stimulation enhances ovulation of queen ovaries treated using a combination of eCG and hCG.

Follicular changes throughout the oestrous phase have been poorly documented in queens because of the location and the small size of ovaries. We investigated follicular development in queens treated with a combination of equine chorionic gonadotropin (eCG) and human chorionic gonadotropin (hCG) and evaluated the effects of vaginal stimulation by a tomcat on ovulation induction. A hormonal treatment was administered using a simple crossover design. Four queens were administered 150 IU of eCG (day 1) and 250 IU of hCG on day 5 and 6. Half of the queens were mated with a vasectomised tomcat for 3 days after hCG injection. Ultrasound imaging of the ovaries clamped at a subcutaneous site was performed once a day from day 1 to 7, and on day 13, and the serum concentrations of oestradiol and progesterone were examined on day 1, 5, 7 and 13. The mean number of follicles gradually increased with the eCG treatment and decreased after hCG injection. The ovulation rate of follicles was significantly higher in the vaginal stimulation group (70.0%) than in the control group (42.6%). During the hormonal treatments, the serum concentration of oestradiol and progesterone did not differ between the two groups. Ultrasound imaging of the ovaries clamped at a subcutaneous site showed that eCG and hCG treatment promoted the follicular growth and corpus luteum formation, respectively. The combination of hCG injection with vaginal stimulation by a vasectomised tomcat enhanced the ovulation rate of follicles.

Inducing ovulation with human chorionic gonadotrophin improves the pregnancy rate in lactating dairy cows receiving an in vitro-produced embryo.

While the global use of in vitro-produced embryos in dairy cattle is on the rise, several technical aspects of embryo transfer procedures have not yet been optimized. This study compares the effects of inducing ovulation using human chorionic gonadotropin (hCG) versus gonadotropin-releasing hormone (GnRH) at the end of a 5-day progesterone(P4)-based protocol for oestrous synchronization on the pregnancy rate of lactating dairy cow recipients of in vitro-produced embryos. Fresh embryos were transferred on Day-seven post-oestrus to ovulating cows receiving GnRH or hCG (groups GnRH and hCG, n = 60 each). Pregnancy was diagnosed by ultrasound on Day 28 post-oestrus. Forty-nine cows became pregnant: 16 in GnRH (26.7%) and 33 in hCG (55%). Taking GnRH-treated cows as reference, the odds ratio for pregnancy of hCG-treated cows was 3.3 (p = .002). In conclusion, hCG treatment given at the end of a 5-day P4-based protocol for oestrous synchronization improved the pregnancy rate in lactating dairy cows receiving an in vitro-produced embryo.

Use of estradiol cypionate to induce ovulation in buffalo raised in floodplain areas of Itacoatiara, Amazonas / [Uso do cipionato de estradiol na indução da ovulação de búfalas criadas em várzea da região de Itacoatiara, Amazonas]

This study aimed to determine the efficiency of estradiol cypionate (EC) as an ovulation inducer in a Timed Artificial Insemination protocol. 69 buffalo cows received an intravaginal progesterone device and 2mg of estradiol benzoate (EB) at D0. On D9, the intravaginal device was removed and 0.53mg of prostaglandin (PGF2α) and 400UI of equine chorionic gonadotrophin (eCG) were applied. The cows were distributed into two groups: the first group received 1mg of EC (ECG) in D9, and the second group received 1mg of EB (EBG) in D10. Inseminations occurred on D11. Ovarian activity and pregnancy diagnosis were analyzed by ultrasonography. There was no difference (P>0.05) in follicular diameter (9.6 ± 0.89mm vs. 10.7 ± 1.12mm; P=0.06), in ovulation rate (90.9% vs. 90.9%; P=1) and pregnancy rate (58.8% vs. 62.9%; P=0.79), however, buffalo cows from the ECG treatment have less time between P4 removal and ovulation when compared to EBG buffalos (37.4h vs. 52.8h; P=0.001), respectively. Thus, it was concluded that the implantation of TAI in the floodplain of Amazonas is feasible and the use of EC results in successful rates, similar to EB.(AU)

O objetivo deste trabalho foi determinar a eficiência do cipionato de estradiol (CE) como indutor de ovulação em um protocolo de inseminação artificial de tempo fixo. Para isso, 69 búfalas receberam no D0 um dispositivo intravaginal de progesterona e 2mg de benzoato de estradiol (BE). No D9, o dispositivo intravaginal foi removido e foram aplicados 0,53mg de prostaglandina (PGF2α) e 400UI de gonadotrofina coriônica equina (eCG), para, então, os animais serem divididos em dois grupos: um deles (GCE) recebeu 1mg de CE no D9, e o outro (GBE) recebeu 1mg de BE 24h após. As inseminações ocorreram no D11. A atividade ovariana e o diagnóstico de prenhez foram avaliados por ultrassonografia. Não houve diferença (P>0,05) no diâmetro folicular (9,6 ± 0,89mm vs. 10,7 ± 1,12mm; P=0,06), na taxa de ovulação (90,9% vs. 90,9%; P=1) e na taxa de prenhez (58,8% vs. 62,9%; P=0,79), no entanto búfalas do tratamento GCE apresentaram menor tempo entre a remoção da P4 e a ovulação, quando comparadas com as búfalas do GBE (37,4h vs. 52,8h; P=0,001), respectivamente. A implantação da IATF nas várzeas do Amazonas é viável e a utilização do CE resulta em taxas de sucesso similares ao BE.(AU)

Improving ovulation in gilts using anti-inhibin serum treatment combined with fixed-time artificial insemination.

For successful batch farrowing, porcine oestrus and ovulation must be synchronized using fixed-time artificial insemination (FTAI). However, exogenous gonadotropins, which are currently used in FTAI, negatively affect gilt ovulation. Here, we aimed to improve sexually mature gilt superovulation efficiency using passive immunization against inhibin during FTAI. Altrenogest-treated gilts were challenged with 10 ml anti-inhibin serum (AIS group, n = 6), 1,000 IU pregnant mare serum gonadotropin (PMSG group, n = 6), or 10 ml goat serum (control group, n = 6). Gilts in the AIS and PMSG groups were inseminated according to the FTAI protocol, and gilts in the control group were inseminated during natural oestrus. When PMSG was replaced by AIS during FTAI of gilts, ovulation rate and embryos recovered were significantly greater in the AIS group as compared to the other two groups (p < .05). Especially the average number of 6-8-cell embryos in the AIS group was significantly higher than that in the PMSG group (p < .01). Moreover, the blastocyst number in the AIS group was significantly higher than that in the PMSG group and the control group (p < .05). But there was no significant difference in the blastocyst number between the PMSG group and the control group (p > .05). Besides, plasma levels of estradiol-ß (E2) and progesterone (P4) were significantly greater in the AIS group as compared to the other two groups on Day 23 and D 27, respectively (p < .01). In summary, we devised an improved high-yield FTAI protocol for sexually mature gilts using AIS; this protocol had a greater superovulation efficiency than the FTAI using PMSG.

Analysis of bovine blastocysts indicates ovarian stimulation does not induce chromosome errors, nor discordance between inner-cell mass and trophectoderm lineages.

Contemporary systems for oocyte retrieval and culture of both cattle and human embryos are suboptimal with respect to pregnancy outcomes following transfer. In humans, chromosome abnormalities are the leading cause of early pregnancy loss in assisted reproduction. Consequently, pre-implantation genetic testing for aneuploidy (PGT-A) is widespread and there is considerable interest in its application to identify suitable cattle IVP embryos for transfer. Here we report on the nature and extent of chromosomal abnormalities following transvaginal follicular aspiration (OPU) and IVP in cattle. Nine sexually mature Holstein heifers underwent nine sequential cycles of OPU-IVP (six non-stimulated and three stimulated cycles), generating 459 blastocysts from 783 oocytes. We adopted a SNP-array approach normally employed in genomic evaluations but reanalysed (Turner et al., 2019; Theriogenology125: 249) to detect levels of meiotic aneuploidy. Specifically, we asked whether ovarian stimulation increased the level of aneuploidy in either trophectoderm (TE) or inner-cell mass (ICM) lineages of blastocysts generated from OPU-IVP cycles. The proportion of Day 8 blastocysts of inseminated was greater (P < 0.001) for stimulated than non-stimulated cycles (0.712 ± 0.0288 vs. 0.466 ± 0.0360), but the overall proportion aneuploidy was similar for both groups (0.241 ± 0.0231). Most abnormalities consisted of meiotic trisomies. Twenty in vivo derived blastocysts recovered from the same donors were all euploid, thus indicating that 24 h of maturation is primarily responsible for aneuploidy induction. Chromosomal errors in OPU-IVP blastocysts decreased (P < 0.001) proportionately as stage/grade improved (from 0.373 for expanded Grade 2 to 0.128 for hatching Grade 1 blastocysts). Importantly, there was a high degree of concordance in the incidence of aneuploidy between TE and ICM lineages. Proportionately, 0.94 were "perfectly concordant" (i.e. identical result in both); 0.01 were imperfectly concordant (differing abnormalities detected); 0.05 were discordant; of which 0.03 detected a potentially lethal TE abnormality (false positives), leaving only 0.02 false negatives. These data support the use of TE biopsies for PGT-A in embryos undergoing genomic evaluation in cattle breeding. Finally, we report chromosome-specific errors and a high degree of variability in the incidence of aneuploidy between donors, suggesting a genetic contribution that merits further investigation.

Effect of the subdose of human chorionic gonadotropin applied in the Hou Hai acupoint on ovulation induction in mares / [Efeito da subdose de gonadotrofina coriônica humana aplicada no acuponto Hou Hai sobre a indução da ovulação em éguas]

The objective of this study was to evaluate the effects of an hCG sub dose applied at the Hou Hai acupoint on corpus luteum (CL) quality and ovulation induction in mares. Fifteen crossbred mares were distributed in randomized blocks and used in three periods with each period employed as the blocking factor in three treatments: T1 = 1500 IU of hCG via intravenous (IV); T2 = 450 IU of hCG applied at the false acupoint (IV); and T3 = 450 IU of hCG applied at the Hou Hai acupoint. Mean diameter of the CL, serum concentration of progesterone (P4), vascularization of the pre-ovulatory follicle and CL were evaluated. Females administered 450 IU of hCG at the Hou Hai acupoint exhibited greater ovulation rates (33.33%) 48h after induction; The minimum number of colored pixel (NCP) of the pre-ovulatory follicle of control females was superior (40.33) to that of mares administered 450 IU of hCG IV at the false acupoint (36.84) and similar to that of those administered hCG at the Hou Hai acupoint (39.31). Further, moderately positive correlations were found between the CL diameter and the P4 concentration on D8 (P<0.05). IV administration of 450 IU of hCG or at the Hou Hai acupoint was efficient at inducing ovulation and ensuring the quality of CL in mares.(AU)

O objetivo foi avaliar os efeitos de uma subdose de hCG aplicada no acuponto Hou Hai na qualidade do corpo lúteo (CL) e na indução da ovulação em éguas. Quinze éguas mestiças foram distribuídas em blocos ao acaso, sendo o período utilizado como fator de blocagem, em: T1 = 1500 UI de hCG por via intravenosa (IV); T2 = 450 UI de hCG aplicado no falso acuponto (IV) e T3 = 450 UI de hCG aplicada no acuponto Hou Hai. Avaliou-se diâmetro médio do CL, concentração sérica de progesterona (P4), vascularização do folículo pré-ovulatório e do CL. As fêmeas que receberam 450 UI de hCG no acuponto Hou Hai apresentaram maiores taxas de ovulação (33,33%) 48h após a indução. O número de pixels coloridos (NPC) mínimo do folículo pré-ovulatório das fêmeas do grupo controle foi superior (40,33) ao das éguas que receberam 450 UI de hCG IV no falso acuponto (36,84) e semelhante ao das éguas que receberam hCG no acuponto Hou Hai (39,31); correlações moderadamente positivas foram encontradas entre o diâmetro do CL e a concentração de P4, ambos no D8 (P <0,05). A administração IV de 450 UI de hCG ou no acuponto Hou Hai foi eficiente na indução da ovulação e na garantia da qualidade do CL nas éguas.(AU)

Effect of ovarian stimulation by different gonadotrophin treatments on in vivo and in vitro reproductive efficiency of rabbit does under high ambient temperature.

Non-lactating multiparous NZW rabbit does (n = 227) were used in two experiments. In the 1st experiment (n = 87), does were i.m. injected with 0.1-ml saline/doe in day 0 (control, n = 29). Other does were injected with 25 IU equine chorionic gonadotrophin (eCG), followed by 0.2-ml gonadotrophin-releasing hormone (GnRH, n = 29) or 75 IU human chorionic gonadotrophin (hCG, n = 29) per doe 48 h later. After 60 h of day 0, does in all groups were artificially inseminated (AI). In the 2nd experiment, does (n = 140) were mated (AI) after synchronization of estrus/ovulation with 25 IU eCG, and 75 IU hCG 48 h later. On day 5 post-AI, does were injected with saline (control), 75 IU hCG, 0.2 ml GnRH, or 25 IU eCG per doe. Injection of eCG with GnRH or hCG pre-AI significantly increased corpora lutea number, ovulation rate, total number/doe and recovery rate of embryos, viable embryos, hatched blastocysts, in vivo reproductive parameters, and concentration of progesterone and progesterone/estradiol 17-ß ratio. Injection of eCG on day 5 post-AI significantly improved large and total follicle number, and in vivo reproductive efficiency. The corpora lutea number and impantation sites were significantly increased in the hCG and eCG groups. Fetal loss rate significantly increased only in the GnRH group. Under high ambient temperature, administration of eCG with hCG or GnRH injection pre-AI could be synchronized estrus/ovulation for improving in vivo and in vitro embryo production. In addition, pregnancy outcomes could be enhanced in rabbit does induced to ovulation by a single eCG or hCG dose on day 5 post-AI.