Synchronization Of Ovulation Research Articles

Characterizing pregnancy losses in Bos indicus beef females receiving a fixed-timed artificial insemination protocol

This experiment evaluated pregnancy losses from day 30 of gestation to calving in Bos indicus females, and evaluated if serum haptoglobin concentrations during early gestation impacts subsequent pregnancy losses. A total of 4926 Nelore females were used, being 1802 nulliparous heifers inseminated as yearlings (precocious heifers), 1356 nulliparous heifers inseminated at 24 months of age (conventional heifers), 887 suckling primiparous cows, and 881 suckling multiparous cows. Cows were assigned to an ovulation synchronization + fixed-time artificial insemination (FTAI) protocol from day −11 to 0 of the experiment. Pregnancy status was verified using transrectal ultrasonography on days 30 and 60 after FTAI, via transrectal palpation on day 150 after FTAI, and according to calf birth. Blood samples were collected from all animals diagnosed pregnant on day 30 after FTAI, and analyzed for serum concentrations of haptoglobin and pregnancy associated glycoproteins (PAG). Pregnancy loss was greater (P < 0.01) from day 60–150 of gestation (10.2 %) compared with day 30–60 of gestation (6.0 %) and with day 150 of gestation to calving (7.4 %), and differed (P = 0.04) between these latter two periods. Pregnancy loss from day 30–60 of gestation did not differ (P = 0.26) among parities, whereas total pregnancy losses (day 30 to calving) were greater (P < 0.01) in precocious (28.4 %) and conventional (27.1 %) heifers compared with primiparous (16.4 %) and multiparous (13.0 %) cows. Serum PAG concentrations on day 30 after FTAI were less (P ≤ 0.03) in cows that lost the pregnancy (5.63 ng/mL) from day 30–60 of gestation, as well as those that lost the pregnancy from day 30 to calving (8.59 ng/mL) compared with cohorts that maintained the pregnancy (9.39 and 9.32 ng/mL, respectively). No differences in serum PAG concentrations on day 30 after FTAI were noted (P ≥ 0.23) according to pregnancy losses from day 60 to calving. Serum haptoglobin concentration on day 30 after FTAI also did not differ (P ≥ 0.48) between cows that maintained or lost the pregnancy. This experiment provides novel information about pregnancy losses after day 30 of gestation in B. indicus cattle, with most losses occurring as fetal mortality and not affected by systemic inflammation during early gestation. Pregnancy losses were nearly doubled in precocious and conventional heifers compared with parous cows, demonstrating the relevance of this reproductive failure to B. indicus replacement heifers.

Study of menstrual cycle synchrony in female medical students sharing common accommodation.

Menstrual cycle synchronization is a phenomenon in which menstrual onset shifts progressively closer with time. It is an adoptive conditional phenomenon seen in the females who associate closely and share a common environment. To ascertain whether menstrual cycle synchrony exists in the roommates living in a closed space in a medical hostel. This is a prospective observational study comprising 62 female medical students of a mean age of 22 years living in twin sharing accommodation with a history of regular menses (26-32 days). These participants were followed on a monthly basis for 13 months. Menstrual cycle history was obtained using standardized Google forms. Menstrual cycle initial and final onset differences, expected cycle cut-off values, and absolute differences were calculated. The menstrual cycle synchrony score was obtained by subtracting the expected difference from the onset difference. Wilson's absolute difference method was used for determining menstrual synchrony between pairs. The descriptive analysis was done using mean and standard deviation. One sample t-test was used to assess the synchrony between roommates. P value ≤0.05 was considered as statistically significant. The initial onset difference of the menstrual cycle was 7.58 ± 4.25 days, whereas the final onset difference was 6.06 ± 3.92 days. The calculated synchrony score was -9.28 ± 5.05, which was statistically significant. Menstrual cycle synchrony was observed in 17 pairs (54.8%) and asynchrony in eight pairs (25.8%). Long-term association between roommates has potential to cause menstrual cycle synchrony. It has significant implications in reproductive medicine for reproductive scheduling and family planning.

Uso da farmacopuntura em subdoses hormonais comparada ao método convencional para indução de estro, taxa de prenhez e parto em ovelhas da raça Santa Inês

The use of subdoses of medication applied to acupuncture points produces an effect similar to the conventional dose, with the advantage of having fewer side effects and reducing the cost of treatment. The objective of this work was to evaluate the effectiveness of hormonal subdoses at acupuncture points (acupoints): Bai Hui (lumbosacral space), and VG 1 (Hou Hai). The application was 10% of the dose of prostaglandin hormones (Lutalyse®, Pfizer – SP, Brazil), and equine chorionic gonadotropin - eCG (Novormon®). It was observed that pharmacopuncture can be as efficient as conventional methods of inducing estrus and pregnancy rate in Santa Inês sheep. Pharmacopuncture becomes an alternative to hormonal administration in estrus and ovulation synchronization protocols in sheep.

Pseudo Almost Periodic Synchronization of OVCNNs with Time-Varying Delays and Distributed Delays on Time Scales

Pseudo Almost Periodic Synchronization of OVCNNs with Time-Varying Delays and Distributed Delays on Time Scales

Proteomics approach reveals urinary markers for early pregnancy diagnosis in buffaloes

This study aimed to compare urine proteomics from non- and pregnant buffaloes in order to identify potential biomarkers of early pregnancy. Forty-four females underwent hormonal ovulation synchronization and were randomly divided into two experimental groups: inseminated (n = 30) and non-inseminated (n = 14). The pregnant females were further divided into two groups: pregnant at Day 12 (P12; n = 8) and at Day 18 (P18; n = 8) post-ovulation. The non-pregnant group was also subdivided into two groups: non-pregnant at Day 12 (NP12; n = 7) and at Day 18 (NP18; n = 7). Urine was collected from all females on Days 12 or 18. The samples were processed for proteomics. A total of 798 proteins were reported in the urine considering all groups. The differential proteins play essential roles during pregnancy, acting in cellular transport and metabolism, endometrial remodeling, embryonic protection, and degradation of defective proteins. We suggest that some proteins from our study can be considered biomarkers for early pregnancy diagnosis, since they were increased in pregnant buffaloes. SignificanceMacromolecules have been studied for early pregnancy diagnosis, aiming to increase reproductive efficiency in cattle and buffaloes. Direct methods such as rectal palpation and ultrasonography have been considered late. Thus, this study aimed to compare urine proteomics from non- and pregnant buffaloes to identify potential biomarkers of early pregnancy. The differential proteins found in our study play essential roles during pregnancy, acting in cellular transport and metabolism, endometrial remodeling, embryonic protection, and degradation of defective proteins. We suggest that these proteins can be considered possible biomarkers for early pregnancy diagnosis since they were increased in the pregnant buffaloes.

Almost periodic quasi-projective synchronization of delayed fractional-order quaternion-valued neural networks

This paper examines the issue of almost periodic quasi-projective synchronization of delayed fractional-order quaternion-valued neural networks. First, using a direct method rather than decomposing the fractional quaternion-valued system into four equivalent fractional real-valued systems, using Banach’s fixed point theorem, according to the basic properties of fractional calculus and some inequality methods, we obtain that there is a unique almost periodic solution for this class of neural network with some sufficient conditions. Next, by constructing a suitable Lyapunov functional, using the characteristic of the Mittag-Leffler function and the scaling idea of the inequality, the adequate conditions for the quasi-projective synchronization of the established model are derived, and the upper bound of the systematic error is estimated. Finally, further use Matlab is used to carry out two numerical simulations to prove the results of theoretical analysis.

Effects of 17β-estradiol on the uterine luteolytic cascade in bovine females at the end of diestrus

In cattle, 17β-estradiol (E2) is essential for triggering luteolysis via the synthesis of prostaglandin F2α (PGF2α). We aimed to evaluate the effects of E2-treatment on day 15 of the estrous cycle on the transcript abundance of genes involved in the PGF2α synthetic cascade. Nelore heifers (N = 50) were subjected to a hormonal protocol for the synchronization of ovulation. Between days 14 and 23 after estrus, the area (cm2) and blood perfusion (%) of the corpus luteum (CL) and progesterone (P4) plasma concentrations were evaluated daily. On day 15, the heifers were assigned to the Control (2 mL of pure sesame oil, N = 21) or Estradiol group (1 mg of E2 diluted in 2 mL of sesame oil, N = 23). After the treatments at 0 h, uterine biopsies were collected at times 1.5 h (C1.5h, N = 8 and E1.5h, N = 10) or 3 h (C3h, N = 8 and E3h, N = 11); and blood samples were obtained from 0, 3, 4, 6 and 7 h for the measurement of 13,14-dihydro-15-keto-PGF2α (PGFM) concentrations by ELISA. Transcript abundance was determined by RT-qPCR and protein abundance of ESRβ and OXTR was determined by Western Blotting. The Estradiol group showed greater (P < 0.05) concentrations of PGFM at 6 and 7 h compared to the Control group. A progressive decrease in plasma P4 concentrations characterized a hastened functional luteolysis, followed by structural luteolysis in the Estradiol group (P < 0.05). Among the treatment groups, no significant difference was detected for the abundance of PRKCα, PRKCβ, AKR1B1, PTGS2 and ESRα transcripts (P > 0.05). Estradiol treatment decreased the abundance of PLA2G4A, AKR1C4, and ESRβ both 1.5h and 3h after treatment (P < 0.05). The relative expression of PGR and OXTR was greater in E3h compared to the C3h (P > 0.05). Protein abundance did not differ between treatment groups at either experimental times (P > 0.05). Overall, E2 promoted an increase in PGFM concentrations and the hastening of functional and structural luteolysis in Nelore heifers through the upregulation of PGR and OXTR, demonstrating for the first time that the expression of these receptors within 3 h after E2 stimulus was associated with triggering luteolysis in cattle.

THE INFLUENCE OF SOME CLIMATIC FACTORS ON THE EFFECTIVENESS OF ESTRUS SYNCHRONIZATION IN BEEF OF DAIRY COWS

The aim of this study was to determine the influence of the temperature humidity index (THI) on the efficiency of estrus synchronization on both beef and dairy cows. The research was carried out at APC "Azamat" of the Beskaragai district of the East Kazakhstan region of the Republic of Kazakhstan. The natural and climatic conditions of this zone make it possible to raise both beef and dairy cattle. The study involved 408 Kazakh white-headed cows aged 3 to 5 year.&#x0D; During the experimental period, the data for air temperature (T), relative humidity (φ), wind speed (υ) were collected, and the temperature humidity index (THI) was determined. The data was recorded for 30 days (10 days before synchronization, 10 days during synchronization and 10 days after synchronization). In addition, during the synchronization period, clinical parameters - body temperature (t), pulse (P), respiratory rate (Re) and rumination (R) were measured daily in 10% of animals by conventional methods.&#x0D; During the experimental period (2020-2022) THI was 74,50±1,31, 78,20±2,11, 72,80±0,7210 days before the estrus synchronization. When THI was increased by 5.6±0.03 in 2021 compared to 2020, the fertility decreased by 9.7±0.78. Similarly, when THI was increased by 7.3 ± 0.56 compared to 2022, fertility was reduced by 13.8 ± 0.36. The latter indicates that when THI increases the fertility rate decreases.&#x0D; Based on the results, there is an influence of THI on the effectiveness of estrus synchronization. Increased THI, to a certain extent, reduces both estrus expression and effectiveness of estrus synchronization leading to reduced fertility rate and increased embryonic mortality.

Comparison of three reproductive management strategies for lactating dairy cows using combination of estrus detection or ovulation synchronization and Fixed-Timed Artificial Insemination

The objective of this study was to compare the reproductive performance of lactating dairy cows submitted to first AI after combination of estrus detection and fixed timed AI (FTAI) and FTAI only. Cows were randomly assigned to receive AI at detected estrus between 50 and 70 d in milk (DIM), if not detected in estrus, were enrolled in either Ovsynch (ED-Ov, n = 485) or PRIDsynch (ED-PR, n = 505) protocols; or received FTAI at 80 DIM after Double-Ovsynch protocol (DO, n = 501). Cows were body condition scored (BCS) at calving and at 43 DIM; and evaluated for postpartum disorders within 7 d postpartum; clinical mastitis, lameness and bovine respiratory disease were recorded until first AI. Ovarian cyclicity was monitored at 43 and 50 DIM, and at 70 and 77 DIM. Pregnancy diagnoses (PD) were performed at 32 and 63 d after AI. Overall prevalence of postpartum anovulation was 7.8%. Pregnancy per AI (P/AI) did not differ between reproductive strategies at 32 d PD (ED-Ov = 43.2%; ED-PR = 41.7%; DO= 45.3%). Primiparous cows had greater P/AI than multiparous cows (53.7% vs 36.8%). Cows on farm 1 had lower P/AI compared with their counterparts on farm 2 (42.1% vs 45.4%). Cows with BCS > 2.5 at 43 DIM had greater P/AI compared with cows with BCS ≤ 2.5 (44.5% vs 34.7%). Similar P/AI for cow’s receiving AI at detected estrus and FTAI, low prevalence of disease anovulation may have contributed to the similar performance of ED-Ov, ED-PR and DO.

Asymptotically almost periodic synchronization in fuzzy competitive neural networks with Caputo-Fabrizio operator

This paper researches a class of Caputo-Fabrizio fractional-order fuzzy competitive neural networks (CF-FCNNs) with different time scales and time delays. Firstly, according to Banach contracting mapping principle and some appropriate assumptions, it derives CF-FCNNs possess a unique weak solution. Then, exponential Euler difference scheme of discrete-time CF-FCNNs (DCF-FCNNs) is presented by the constant variation methods and the difference format is implicit Euler difference and is solved by fractional PECE algorithm. Next, the existence of a unique bounded asymptotically almost periodic sequence solution, global exponential stability and synchronization of DCF-FCNNs are considered. In the end, numerical examples are given to describe the effectiveness of the acquired conclusions.

Finite-time complete periodic synchronization of memristive neural networks with mixed delays

In this paper we study the oscillatory behavior of a new class of memristor based neural networks with mixed delays and we prove the existence and uniqueness of the periodic solution of the system based on the concept of Filippov solutions of the differential equation with discontinuous right-hand side. In addition, some assumptions are determined to guarantee the globally exponentially stability of the solution. Then, we study the adaptive finite-time complete periodic synchronization problem and by applying Lyapunov–Krasovskii functional approach, a new adaptive controller and adaptive update rule have been developed. A useful finite-time complete synchronization condition is established in terms of linear matrix inequalities. Finally, an illustrative simulation is given to substantiate the main results.

Effect of delayed timing of artificial insemination with sex-sorted semen on pregnancy per artificial insemination in synchronized dairy heifers managed in a seasonal-calving pasture-based system

The objective of this study was to evaluate the timing of artificial insemination (AI) with frozen-thawed sex-sorted semen on pregnancy per AI (P/AI) in dairy heifers. A 6-d progesterone Co-Synch protocol was used for ovulation synchronization of dairy heifers, with timed AI (TAI) coincident with (TAI-0) or 8 h (TAI-8) after the second injection of GnRH, corresponding to either 48 h or 56 h after removal of the progesterone-releasing intravaginal device. Pregnancy diagnosis was conducted by transrectal ultrasound scanning of the uterus 34 d after TAI (n = 816 records available for analysis). Generalized linear mixed models were used to examine the effects of treatment on P/AI. Treatment (n = 2), herd (n = 11), and treatment × herd were included as categorical fixed effects. Heifer body weight and Economic Breeding Index values for milk production, fertility, calving performance, beef carcass, cow maintenance, cow management, and health were included as continuous fixed effects. Heifer ID was included as a random effect. Pregnancy per AI was greater for TAI-8 heifers (59%) compared with TAI-0 heifers (50%). Pregnancy per AI ranged from 38% to 75% between herds but there was no treatment × herd interaction. The fertility subindex (positive) and the cow management subindex (negative) were the only continuous animal variables associated with P/AI. Delaying the timing of AI with frozen-thawed sex-sorted semen by 8 h in dairy heifers enrolled on a 6-d progesterone Co-Synch protocol improved P/AI.

The Waves and Cycles of COVID-19 Pandemic: A Phase Synchronization Approach

This study pretends to contribute to a better understanding of the COVID-19 dynamics through the non-parametric technique of phase synchronization by comparing the fifteen most affected countries by the number of positive cases plus China, where the firstoutbreak took place in December 2019. It was possible to state the number of cycles and waves for each one of the studied countries and to determine periods of synchronization between them. The results also showed the average duration of the cycles and some coincidences regarding Nason (2020); Bontempi (2021); Coccia (2021); Rusiñol, Zammit, Itarte, Forés, Martı́nez-Puchol, Girones, Borrego, Corominas, and Bofill-Mas (2021). This study is limited by the reliability of the number of positive cases reported by national governments and health authorities because of an insufficient number of tests and a great number of asymptomatic persons but presents a legit alternative to predict the evolution of the pandemic in a country due to the forward looking behavior of another one, therefore studies like this could be useful to implement contention measures and to prepare the health systems in advance.

Weighted Pseudo Almost Periodic Synchronization for Clifford-Valued Neural Networks with Leakage Delay and Proportional Delay

Weighted Pseudo Almost Periodic Synchronization for Clifford-Valued Neural Networks with Leakage Delay and Proportional Delay

Estrus and ovulation synchrony of buffaloes (Bubalus bubalis): A review

Synchronizing estrus and ovulation in buffalo using timed inseminations (TAI) protocols circumvents the limitations associated with estrus detection. Spontaneous estrus in buffalo may achieve more conception rate on insemination than those subjected to synchronization of estrus and timed insemination (TAI). The advantages of insemination following synchronization programs include higher detection rates combined with decreased embryonic losses and reduction in days open. A synchonization programme should ensure control of estrus cycle which entirely depends on ovarian status of animals before starting any protocol. Ovarian follicular status at the beginning of treatment protocols plays vital role for effective response shown by animals. Studies show that more precise alterations in follicular waves may be needed to achieve better synchrony of ovulation and more fertility. The protocols which use Gonadotropic Releasing Hormone (GnRH), follicle stimulating hormone (FSH), luteinizing hormone (LH), equine chorionic gonadotropin (eCG), human chorionic gonadotropin (hCG), prostaglandins, progesterone and estradiol have been helpful in achieving the estrus and ovulation synchrony. Use of estradiol esters and progesterone per-vaginum implants have also been incorporated in synchronization programs. Synchronous emergence of follicular waves using trans-vaginal ultrasound guided follicular ablation and estradiol administration is a recent concept for synchronization in buffalo. Further, a recent approach has been to allow the follicle of second follicular wave to ovulate as the fertility has been lesser when first wave follicle ovulates. Moreover, controlling environmental influences, nutritional and managemental strategies remain pre-requisite to achieve desired goals though hormonal administration. This is more particular in buffaloes suffering from anestrum more so in low or non-breeding season and pre-pubetal anestrum. This review will cover the available documented literature regarding estrous cycle physiology with emphasis on follicular wave dynamics and the future area of work to be focused to achieve more reproductive efficiency in buffalo.

GnRH34 with or without estradiol cypionate in timed AI in Bos indicus beef cows

Two experiments were performed to evaluate the effects of GnRH treatment on the fertility of suckled Nelore beef cows treated with an estradiol/progesterone (E2/P4)-based protocol for timed artificial insemination (TAI). Experiment 1 focused on determining the effects of estradiol cypionate (EC) on ovulation in TAI cows treated with GnRH 34 h after removal of the intravaginal P4 device (IPD). Suckled cows (n = 26) were treated with 2 mg estradiol benzoate (EB) and IPD containing 1 g P4. After 8 days, IPDs were removed, and all cows were treated with 150 μg of d-cloprostenol (prostaglandin F2 alpha analog) and 300 IU of equine chorionic gonadotropin (eCG), then separated into two treatment groups consisting of cows who received 1) saline 0.9% i.m. (GnRH34 group) or 2) 0.6 mg i.m. of EC (EC-GnRH34 group). On day 9 (05:00 p.m.), all cows were given GnRH (10.5 μg of buserelin acetate) i.m. No differences were observed between the groups (P > 0.05) in the time of ovulation after IPD removal or in the proportion of cows ovulating. Experiment 2 focused on determining the effects of GnRH34 along with or in the absence of EC on day 8 on pregnancy per AI (P/AI) in postpartum beef cows. Cows (n = 981) were treated similarly to those in Experiment 1, but an additional group, the EC-GnRH48 group, was included, in which cows received EC on day 8 whereas those that did not show estrus received GnRH at TAI. Thus, in this experiment, groups consisted of GnRH34 (n = 322), EC-GnRH34 (n = 335), and EC-GnRH48 (n = 324). A higher rate of estrus expression was observed in cows treated with EC following IPD removal (EC-GnRH34: 69%, EC-GnRH48: 64.8%) than in cows in the GnRH34 group (45.6%). No difference in P/AI was observed between the treatment groups (P = 0.45), but P/AI in cows in the EC-GnRH34 group (64.2%) tended to be greater (P = 0.1) than in cows in the GnRH34 group (58%). In summary, although ovulation synchrony did not differ among the groups, P/AI in cows treated with EC and GnRH 34 h after IPD removal tended to be greater than in cows treated solely with GnRH; this was most likely due to a shorter proestrus/estrus period, considering the lower proportion of cows that displayed estrus in the GnRH34 group. Finally, given that P/AI did not differ between the EC-GnRH34 and EC-GnRH48 groups, our results suggest that, for cows not displaying estrus, administration of EC at the time of IPD removal followed by treatment with GnRH 48 h afterward represents the most cost-efficient TAI strategy for South American Zebu-based beef operations.

Analysis for flow termination in the decentralized and centralized pre-congestion notification architecture

This paper discusses decentralized and centralized pre-congestion notification (PCN)-based measured-rate flow termination (FT) in the case of a single bottleneck. The paper finds out that asynchronous measurement periods between ingress–egress aggregates (IEAs) cause overtermination in the decentralized PCN although RFC6661 states that the operation of PCN is not affected if the starting and ending times of the measurement periods for IEAs are different. Also, the paper finds that the asynchronous measurement periods can prevent a FT for one IEA from terminating enough flows in one shot. Furthermore, the paper proves that overtermination occurs in the decentralized PCN due to asynchronous measurement periods regardless of the same or different round trip time (RTT) and synchronous measurement period with different RTTs. In contrast, the centralized PCN can avoid overtermination due to effects of the asynchronous measurement periods and different RTTs.

EFFICACY OF OVULATION SYNCHRONIZATION REGIMENS ON PREGNANCY RATE TO TIMED ARTIFICIAL INSEMINATION IN ACYCLIC POST-PARTUM NILI-RAVI BUFFALOES

The present study compared the two ovulation synchronization treatments combined with a progesterone release device in buffaloes. Ninety acyclic buffaloes were divided into three experimental The blood samples were collected before the start of the trial to determine the reproductive status (anestrous and sub-estrous). In G I and G II, CIDR was inserted for seven days and treated with on the 6th day of protocol. In the protocol, the first estradiol benzoate (EB) and doses were given on day 0 and 2nd EB and doses on day 8 to G I and G II groups, respectively. Whereas, G III served as a control group. The G I and G II groups were observed for heat signs, but fixed time twice AI was done at 48 or 60 hours of CIDR removal, whereas G III was inseminated at detected estrus. The blood samples were also collected prior to the execution of the trial from experimental buffaloes for observing the cyclicity status through serum progesterone level. The results of cyclicity showed 78% anestrous and 22% sub-estrous status in included buffaloes. The effects of synchronization protocols revealed that estrus response was significantly greater in G I and G II groups than in the G III group. The ovulation occurrence, ovulatory follicle szie and pregnancy outcomes were also significantly higher in G I and G II compared to G III. Conclusively, including EB or at the CIDR insertion and removal times effectively enhances estrus, ovulation and pregnancy in sub-estrous and anestrous buffaloes.&#x0D;

Synchronous Rotation in the (136199) Eris–Dysnomia System

We combine photometry of Eris from a 6 month campaign on the Palomar 60 inch telescope in 2015, a 1 month Hubble Space Telescope WFC3 campaign in 2018, and Dark Energy Survey data spanning 2013–2018 to determine a light curve of definitive period 15.771 ± 0.008 days (1σ formal uncertainties), with nearly sinusoidal shape and peak-to-peak flux variation of 3%. This is consistent at part-per-thousand precision with the P = 15.785 90 ± 0.00005 day sidereal period of Dysnomia’s orbit around Eris, strengthening the recent detection of synchronous rotation of Eris by Szakáts et al. with independent data. Photometry from Gaia are consistent with the same light curve. We detect a slope of 0.05 ± 0.01 mag per degree of Eris’s brightness with respect to illumination phase averaged across g, V, and r bands, intermediate between Pluto’s and Charon’s values. Variations of 0.3 mag are detected in Dysnomia’s brightness, plausibly consistent with a double-peaked light curve at the synchronous period. The synchronous rotation of Eris is consistent with simple tidal models initiated with a giant-impact origin of the binary, but is difficult to reconcile with gravitational capture of Dysnomia by Eris. The high albedo contrast between Eris and Dysnomia remains unexplained in the giant-impact scenario.

Comparison of the efficacy of Lecirelin and hCG for ovulation induction in mares

Ovulating agents are very useful drugs in equine breeding, hCG being the first intention molecule, whereas GnRH agonists are especially interesting for any mare immunized against hCG, like repeat breeders and embryo donor mares. In Europe, no long acting GnRH agonist is available in veterinary practice. Saline solutions of buserelin or triptorelin, which is only available for human treatments in Europe are commonly used for equine ovulation induction (Dordas-Perpinya et al. Reprod. Dom. Anim. 2020; 55:374-383). An alternative, Lecirelin which is licensed in cattle and rabbits, has been evaluated in donkeys (Carluccio et al. Therio. 2007;68:914-919). The aim of our study was to compare the efficacy of lecirelin with hCG in horses. Forty mares underwent ovulation induction on four consecutive cycles, two cycles with hCG and two cycles with lecirelin, including one spontaneous estrus and one following chemical luteolysis. Mares were examined on a daily basis to check ovarian follicles diameter, uterine edema, and cervical softening. Once they presented a preovulatory follicle over 35 mm, and uterine edema (>=2) (Mc Kinnon. Equine diagnostic ultrasonography. 1998; 79-102) and a soft cervix, they were randomly injected with saline solution containing 200 µg of Lecirelin or 1500 IU of hCG intravenously. After induction, they were scanned every 12 hours until ovulation. Mares were inseminatedwith a mix of fresh semen of two fertile stallions 20 hours after induction on the spontaneous cycles. Pregnancy diagnosis was performed at day 12 and day 14. As each mare is her own control, statistical analysis was performed by χ², Fisher's test and Student's test for matched data. Follicle size at injection did not differ significantly between the two induction treatments (p>0,05), with or without distinction of spontaneous and induced cycles. Rates of ovulation in the 24-48 hours post-injection did not significantly differ between lecirelin (71%) and hCG (83%) on estrus following chemical luteolysis (p>0,05) or spontaneous estrus (43% for lecirelin and 68% for hCG) (p>0,05). We observed significantly more spontaneous ovulations occurring within the first 24 hours after induction with hCG (27% on spontaneous estrus, and 15% after chemical luteolysis) than with lecirelin (5% on spontaneous estrus, 7% after chemical luteolysis) (p < 0,05). Pregnancy rates were not significantly different following induction by lecirelin (67%) or hCG (57%) (p>0,05). These results highlight the usefulness of saline solution of lecirelin licensed in Europe for bovine and rabbit for induction and synchronization of ovulation for mares with control cycles. Lecirelin may be particularly suitable for embryo donor mares with a reduced hCG response.