Articles de revues : « Ovulation »

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Poonam, Dr, S. Suman, MK Gupta et RK Rauniyar. « The Role of Ultrasound in Ovulation Detection Compared To BBT and Other Methods ». Nepalese Journal of Radiology 3, n^o 2 (15 janvier 2014) : 57–64. http://dx.doi.org/10.3126/njr.v3i2.9608.

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Background: The detection of timing of ovulation is an important step in the evaluation and management of subfertility. Ultrasonography plays a vital role in monitoring follicular growth. Aims: To assess the value of ultrasound scanning of the ovaries in the periovulatory period to detect ovulation and to correlate the results with basal body temperature (BBT) chart and other presumptive evidences of ovulation. Methods: In this prospective study, a total of 60 subfertile patients were selected from the outpatient department of obstetrics and gynaecology, BPKIHS, Dharan. BBT charting, midcycle abdominal pain record & premenstrual endometrial biopsy were performed in all patients i.e. in spontaneous ovulating and anovulating (induced later). Ultrasonographic periovulatory follicular tracking was usually started around 10th day of the cycle. The results were then correlated with BBT mainly and also with mittelschmerz and endometrial biopsy. Results: In this series fifty five patients, who demonstrated sixty ovulations (with failed inductions in five patients) were monitored for hundred ten cycles. The mean preovulatory follicular diameter was 20.55 mm and 21.76 mm in spontaneous and induced cycles respectively. Majority (36%) demonstrated ovulation by disappearance of follicles accompanied by increase in the amount of fluid in the pouch of Douglas (POD). In this study five cases (14.2%) out of thirty five showing biphasic BBT were anovulatoty. Whereas five cases out of twenty one showing monophasic BBT were ovulating. Amongst the inconclusive group, one (25%) patient was ovulating and the rest four (75%) were anovulatoty. Only 35% patients experienced midcycle pain. Ipsilateral pain was commoner (16.6%) than contralateral (6.6%) and central pain (11.6%). Conclusion: Ultrasonographic follicular tracking is a reliable method of ovulation detection. Ovulation precedes the initial rise in temperature in most women confirming the limited value of the rise in BBT as a predictor of ovulation.DOI: http://dx.doi.org/10.3126/njr.v3i2.9608 Nepalese Journal of Radiology Vol.3(2)July-Dec, 2013: 57-64

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Martinez-Ros, Paula, Alejandro Rios-Abellan et Antonio Gonzalez-Bulnes. « Influence of Progesterone-Treatment Length and eCG Administration on Appearance of Estrus Behavior, Ovulatory Success and Fertility in Sheep ». Animals 9, n^o 1 (26 décembre 2018) : 9. http://dx.doi.org/10.3390/ani9010009.

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The present study characterizes, for sheep, the occurrence and timing of the onset of estrus behavior and ovulation and the yields obtained (ovulation rate, progesterone secretion, and fertility) after Controlled Internal Drug Release (CIDR) insertion for five, six, seven, or fourteen days, with or without equine chorionic gonadotrophin (eCG) in ewes of the Segureña meat breed. All the treatments showed above 80% of females displaying estrus, but the onset of estrus was earlier and more synchronized when using eCG and, among groups with eCG, onset of estrus was earlier in the sheep treated for 14 days than in the short-term treatments (p < 0.05 for all). Administration of eCG after either short- or long-term treatments assured the occurrence of fertile ovulations in all the animals. Conversely, ovulatory success without eCG was found to be dependent on treatment length, with a high percentage of animals ovulating after five days of treatment (83.3%) and very low percentages after treatment for six or seven days (40% and 20%, respectively). Ovulation rate and progesterone secretion were similar among animals ovulating, but ovulation failures predetermined the fertility yields obtained in response to the treatments. Hence, the best results were found after treatment for 14 days plus eCG, and for 5 days without eCG (83.3 for both, p < 0.05 when compared to the other groups with different treatment lengths and with or without eCG).

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Ginther, O. J., M. O. Gastal, E. L. Gastal, J. C. Jacob et M. A. Beg. « Induction of haemorrhagic anovulatory follicles in mares ». Reproduction, Fertility and Development 20, n^o 8 (2008) : 947. http://dx.doi.org/10.1071/rd08136.

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A follicular wave and luteolysis were induced in mares by ablation of follicles ≥6 mm and treatment with prostaglandin F2α (PGF) on Day 10 (where ovulation = Day 0). The incidence of haemorrhagic anovulatory follicles (HAFs) in the induced waves (20%) was greater (P < 0.007) than in preceding spontaneous waves (2%). Hormone and follicle dynamics were compared between induced follicular waves that ended in ovulations (ovulating group; n = 36) v. HAFs (HAF group; n = 9). The day of the first ovulation or the beginning of HAF formation at the end of an induced wave was designated as post-treatment Day 0. The mean 13-day interval from Day 10 (PGF and ablation) to the post-treatment ovulation was normalised into Days 10 to 16, followed by Day –6 to Day 0 relative to the post-treatment ovulation. Concentrations of LH were greater (P < 0.05) in the HAF group than in the ovulating group on Days 10, 11, 12, 14, –3 and –2. The HAF group had greater (P < 0.003) LH concentrations on Day 10 of the preceding oestrous cycle with spontaneous ovulatory waves. The diameter of the largest follicle was less (P < 0.05) in the HAF group on most days between Day 13 and Day –1 and this was attributable to later (P < 0.002) emergence of the future largest follicle at 6 mm in the HAF group (Day 12.4 ± 0.5) than in the ovulating group (Day 11.3 ± 0.1). The results indicate that the high incidence of HAFs after PGF and ablation was associated with later follicle emergence and immediate and continuing greater LH concentration after PGF treatment, apparently augmented by an inherently high pretreatment LH concentration.

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Buranaamnuay, K., P. Tummaruk et M. Techakumphu. « 15 INTRAUTERINE INSEMINATION USING FROZEN - THAWED BOAR SEMEN IN SPONTANEOUS AND INDUCED OVULATING SOWS UNDER FIELD CONDITIONS ». Reproduction, Fertility and Development 22, n^o 1 (2010) : 165. http://dx.doi.org/10.1071/rdv22n1ab15.

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Intrauterine insemination (IUI) using frozen-thawed (FT) boar semen has yet to be reported. The objective of the present study was therefore to evaluate the 24-day nonreturn rate (NR), farrowing rate (FR), number of total piglets born/litter (TB), and number of live born piglets/litter (BA) after IUI with FT boar semen in spontaneous and induced ovulating sows. Ejaculates collected from each of 6 boars [3 Landrace (L) and 3 Yorkshire (Y)] were cryopreserved separately and used to produce LY crossbred offspring. Each batch of qualifying FT semen (≥30% motility) was divided and used in both groups, to minimize an individual boar variation effect. Thawed semen containing 1 × 109 motile spermatozoa extended in 20 mL of Beltsville Thawing Solution extender was flushed into the uterine body (20 mm beyond the cervix) via IUI device (Deep goldenpig™ catheter, IMV Technologies, L’Aigle, France). Forty multiparous sows (20 L and 20 Y) with weaning to estrus interval of 3 to 7 days were randomly assigned to 1 of 2 groups: spontaneously ovulating sows (10 L and 10 Y) and hCG-induced ovulating sows (10 L and 10 Y). The sows with spontaneous ovulation did not receive any treatment. The induced ovulating sows were given 750 IUhCG i.m. at detection of estrus. Ovulation was investigated every 12 h using transrectal ultrasonography. Time of ovulation was determined as 6 h before the first time when preovulatory follicles were not found. Insemination was conducted at 24 h after the detection of estrus and repeated every 12 h until ovulation took place in the spontaneous ovulation group and at 36, 42, and/or 48 h after hCG administration in the induced ovulation group. The statistical analyses were carried out using SAS software (version 9.0, SAS Institute, Cary, NC, USA.). The interval from detection of estrus to ovulation (EOI), TB, and BA were compared between the groups using Student’s t-test; and NR and FR between groups were compared using chi-square test. P < 0.05 was considered statistically significant. The results revealed that sow breed and sow breed interacted with group had no influence on any parameter assessed (P > 0.05). The average EOI differed significantly between spontaneous ovulation (40.2 h) and induced ovulation groups (35.6 h; P = 0.01). Moreover, variation of EOI among sows within each group seemed to be lower in the induce ovulation (4.5 h SD) than in spontaneous ovulation (5.5 h SD; P = 0.5). The number of inseminations per sow was 2.9 ± 0.6 (2 to 4 times) in spontaneously ovulating sows and was 2.4 ± 0.5 (2 to 3 times) in induced ovulating sows. No significant differences (P > 0.05) were found in the NR (80 v. 85%), FR (60 v. 65%), TB (8.0 ± 2.8 v. 9.4 ± 3.7 piglets/litter), and BA (7.8 ± 2.8 v. 8.7 ± 3.7 piglets/litter) between spontaneous and induced ovulating sows. In conclusion, IUI with a low number of FT boar spermatozoa provided fairly good NR and reasonable FR and TB in both spontaneous and induced ovulating sows. The number of inseminations required to attain acceptable fertility tended to be lower in the weaned sows with induced ovulation.

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Fogarty, NM, DG Hall et AR Gilmour. « Performance of crossbred progeny of Trangie Fertility Merino and Booroola Merino rams and Poll Dorset ewes. 2. Reproductive activity, liveweight and wool production of ewe lambs ». Australian Journal of Experimental Agriculture 35, n^o 8 (1995) : 1075. http://dx.doi.org/10.1071/ea9951075.

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Liveweight, wool production, oestrous expression and ovulation rates of 260 Trangie Fertility Merino x Dorset (TD) and 278 Booroola Merino x Dorset (BD) ewes born in late winter-spring over 4 different years were analysed from post-weaning to first joining at about 19 months of age. The percentage of ewes expressing oestrus reached a peak of 68% in May-June, declined to 7% in September and rose to 93% in January prior to first joining. The proportion of ewes ovulating followed a similar pattern. The proportion of ewes expressing oestrus in March, May and June increased (P<0.001) substantially with increasing age and liveweight, which accounted to some extent for the large differences in oestrous activity between years. There was little difference between the strains in proportion of ewes expressing oestrus or ovulating throughout the year. TD ewes were heavier (P<0.001) than BD ewes, the difference increasing from 2 to 4 kg at 7 and 19 months. They also produced 0.3 kg more clean wool which had 1.2 pm higher fibre diameter (P<0.001). Ovulation rate, measured in each of 2 years at 2-monthly intervals, increased from 7 to 19 months of age. BD ewes had a higher ovulation rate than TD ewes on all occasions, and the difference averaged +0.4 ovulations. The mean ovulation rate in February (19 months) for ewes born over 3 years was 2.1 ova for BD and 1.4 ova for TD ewes (P<0.001). Based on subsequent ovulation rate and litter size records, 42% of the BD ewes were identified as carriers of the FecB gene. Ages at first oestrus and ovulation varied considerably between years (P<0.001). There was no difference between the strains in age at first oestrus, although BD ewes first ovulated at a younger age (P<0.05) than TD ewes. The stud of origin of the dam, dam age, dam parity and birth type were not significant for any reproduction trait. There was significant (P<0.001) variation in liveweight due to the origin of the dam. Half-sib estimates of heritability for ewe liveweight, ovulation rate at various seasons and wool production traits were generally high with relatively high standard errors as they were based on 23-40 degrees of freedom for sire.

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Iglesias, R. M. Rodriguez, C. Giglioli, N. Latimori et H. Irazoqui. « Ovulation rate of Lincoln ewes at Bahia Blanca, Argentina ». Animal Science 45, n^o 3 (décembre 1987) : 459–64. http://dx.doi.org/10.1017/s0003356100002944.

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ABSTRACTAn experiment was carried out at Bahia Blanca (38°44' S, 62°10' W) to estimate the seasonal variation in ovulation rate and its components shown by Lincoln ewes of constant live weight.Twenty-three 5-year-old ewes were subjected to nine 17-day observation periods which were evenly spaced within 405 days.Percentage of ewes showing oestrus and ovulation, incidence of multiple ovulations and ovulation rate were estimated for each period by using vasectomized rams and performing iaparoscopies.Traits showed a similar seasonality which was presumably induced by the natural light regime to which the ewes became exposed before and during each observation period.A significant and periodic relationship was found between each trait and the number of days elapsed from the longest day.The predicted maximum values for each parameter were reached about 40 days before the shortest day. Prior to and after this date both the percentage of ewes showing oestrus and ovulation and the incidence of multiple ovulations declined so that the expected ovulation rate values became zero for a period of about 3 months before the longest day.

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Ferreira-Silva, José Carlos, Pábola Santos Nascimento, Marcelo Tigre Moura, Sarah Romini Lima Basto, Marlon Vasconcelos Azevedo, Jorge Motta Rocha, José Pompeu Santos Filho et Marcos Antonio Lemos Oliveira. « Induction of Ovulation in Mangalarga Marchador Mares by hCG or GnRH ». Acta Scientiae Veterinariae 46, n^o 1 (10 mars 2018) : 6. http://dx.doi.org/10.22456/1679-9216.86667.

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Background: Induction of ovulation is a key procedure for horse assisted reproduction technologies, such as for artificial insemination (AI) and embryo transfer. The application of hCG remains as the primary ovulation-inducing agent for horse assisted reproduction, but alternatives are in demand to avoid its adverse effects, such as loss of ovulation-inducing efficiency over multiple applications by hCC-antibody production. Despite reports on alternative ovulation-inducing agents, pair-wise comparisons of such agents under similar conditions have been limited. Under such scenario, the work was aimed to determine the efficiency of both hCG and Buserelin at inducing ovulation in Mangalarga Marchador mares raised in the Northeast of Brazil under an AI program.Materials, Methods & Results: Mares were initially selected based on their reproductive performance, the absence of clinical-reproductive alterations and adequate body condition score. Mares in diestrus were randomly distributed in three experimental conditions, received 5 mg of Dinoprost and were monitored daily for estrus detection. After estrus detection, ovaries were monitored by ultrasonography, in 12-h intervals, until the follicle reached 35 mm. At this time-point, ovulation was induced with 0.042 mg of Buserelin endovenously, with 3,000 IU hCG by an intramuscular shot, and control mares received 2 mL of saline solution, also by an intramuscular shot. Both hCG and Buserelin displayed similar efficiencies (P > 0.05) for induction of ovulation and that both agents were effective (P < 0.05) for such purpose, since greater percentages (P < 0.05) of induction on mares treated from those of the control. Moreover, the total number of ovulations in mares treated at the end of the experiment was not different (P > 0.05) from those found in the Control. All ovulations occurred within a 72-h period after treatment. It can be observed that in mares treated with hCG or Buserelin, ovulations occurred both in more mares (P < 0.05) and at earlier time-points than mares from the control. It is also possible to note that pregnancy was not different (P > 0.05) between hCG and Buserelin groups, and that pregnancy of mares treated with ovulation-inducing factors was similar to the control.Discussion: The majority of ovulations in mares occurred within initial 48-h after treatment for both hCG and GnRH, suggesting a similar potential for horse assisted reproduction. Both hCG and Buserelin are two commonly used agents for induction of ovulation in mares. As described here, the majority of ovulations occurred within initial 48-h after treatment, a fact which can be attributed to hCG and GnRH activity, since it can happen in intervals from 36 to 48-h after treatment. Pregnancy rates did not differ among groups. These results are under the working hypothesis that hCG and Buserelin would display similar efficiencies on pregnancy rates. Despite the understanding of hCG activity on induction of ovulation due to its high specificity toward LH receptors and results from a direct effect on diminishing estradiol concentration, increasing LH, and further inducing ovulation within 48-h after treatment. In contrast, Buserelin has a similar functional property but acts upon LH synthesis and its release. In conclusion, ovulation in mares can be induced with both hCG and Buserelin, and both ovulation-inducing agents do not affect pregnancy rates.

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Dawson, A., R. L. Pitt, S. J. Ward, M. J. Warren, N. D. Cameron et A. R. Peters. « The effect of mating sows in the early oestrus period on duration and timing of ovulation ». Proceedings of the British Society of Animal Science 1997 (1997) : 81. http://dx.doi.org/10.1017/s1752756200595222.

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The duration of ovulation in pigs may contribute to embryo mortality, as later ovulated ova, which become the least mature embryos, are unable to contend with the changing uterine environment (Pope, 1992). The shorter ovulation of spontaneously ovulating sows, which were mated, compared to induced sows, which were not mated (Soede et al, 1992), suggested that the mating itself may reduce the length of ovulation. The current study determined the effect of mating in the early oestrus period on both the timing and duration in recendy weaned, spontaneously ovulating sows.

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Murtaza, A., M. I. R. Khan, W. Ahmad, T. Sohail, I. Mohsin, M. Shahzad, M. Hussain et M. Z. Tahir. « 118 A retrospective analysis of follicular dynamics, LH, estradiol-17β, and progesterone in prostaglandin F2α-induced estrus of Beetal goats ». Reproduction, Fertility and Development 31, n^o 1 (2019) : 185. http://dx.doi.org/10.1071/rdv31n1ab118.

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The objective of the study was to reveal the factors associated with variable interval to ovulation following a single dose of prostaglandin F2α (PGF2) in Beetal goats. In experiment 1, the extent of ovulation time was demonstrated after synchronizing Beetal goats (n=38) by using a single injection of PGF2 based on corpus luteum detection by B-mode transrectal ultrasonography. Ovulations were detected every 6h from PGF2 until ovulation. To explore the changes in follicular dynamics, endocrine profiles and behavioural events due to the variation in the interval to ovulation, another set of goats (n=13; experiment 2) were synchronized by a single dose of PGF2 given at random days of the luteal phase. Follicular dynamics were monitored every 12h from PGF2 until ovulation and oestrus was detected by apronized bucks every 6h from PGF2 treatment. Blood sampling (3mL) for oestradiol-17β and progesterone was done every 12h from PGF2 until ovulation and every 2h for LH assay by radioimmunoassay. Data were analysed by Student’s t-test, general linear models, and Pearson coefficient correlation (SPSS, version 20.0, SPSS Inc., Chicago, IL, USA). Results revealed that ovulation time varied from 60 to 96h after PGF2, and 57% of ovulations occurred by 72h after PGF2 (experiment 1). Based on this observation, goats (n=13) in second experiment were retrospectively divided into early and late ovulators (i.e. 72 and 84h following PGF2, respectively). Onset of oestrus, peak oestradiol-17β concentration, and LH surge after PGF2 were first observed in early than late ovulators (P<0.05). The goats having greater follicle diameter and smaller corpus luteum diameter at the time of PGF2 ovulated earlier than late ovulators (5.4±0.2v. 4.3±0.2mm and 10±0.6v. 11.8±0.3mm, respectively; P<0.05). Likewise, plasma progesterone concentration tended to be lower (P=0.087) in early than late ovulators. However, interval from onset of oestrus to peak LH and ovulation, duration of standing oestrus, interval from LH peak to ovulation, diameter and growth rate of preovulatory follicles, and number of ovulations were similar (P>0.05) between early and late ovulators. In conclusion, the size of dominant follicle and corpus luteum at the time of PGF2 determines the interval to ovulation following a single dose of PGF2 during the luteal phase.

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Hanrahan, J. P. « Divergent selection for ovulation rate in sheep : effect on embryo survival ». Proceedings of the British Society of Animal Production (1972) 1992 (mars 1992) : 44. http://dx.doi.org/10.1017/s0308229600021681.

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The relative importance of genetic variation in ovulation rate and in embryo survival together with the genetic relationship between these traits are important issues in terms of manipulating prolificacy in all multitocous mammalian species. Evidence in sheep, primarily from study of breed differences but also based on results of selection for litter size, shows that genetic variation in litter size is essentially attributable to differences in ovulation rate although genetic differences in embryo survival have been identified. Results from selection on litter size also suggest that genetic variation in ovulation rate is independent of any variation in embryo survival. The evaluation of the relationship between these traits in sheep is somewhat problematical in most populations due to the low level of ovulation and particularly the associated high proportion of ewes which shed a single ovum. The objective of the present study was to use lines of Finn Sheep, a breed with a high ovulation rate and in which single ovulations are rare, which have been developed by divergent selection on ovulation rate to evaluate the genetic association between ovulation rate and embryo survival.

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Glazko, V. I., J. B. Owen, I. Ap Dewi et R. F. E. Axford. « An association of haemoglobin protein (HBB) with ovulation rate in Cambridge sheep ». Animal Science 64, n^o 2 (avril 1997) : 279–82. http://dx.doi.org/10.1017/s1357729800015848.

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AbstractBlood from 106 females (1 to 7 years old) of the Cambridge flock at the University of Wales, Bangor was analysed for 21 protein systems. Of the 11 polymorphic systems, haemoglobin protein (HBB) was found to be significantly associated with ovulation rate as measured by mean ovulation rate for all records per ewe. Mean ovulation rate for the HBB AA genotype was 1·25 ovulations higher than for the AB and BB genotypes (P < 0·001). The results suggest that a gene segregating in this breed is different from the Booroola (FecB) gene and that lambs of either sex can be screened at a young age for a major difference in ovulation rate.

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Pavlicev, Mihaela, Andreja Moset Zupan, Amanda Barry, Savannah Walters, Kristin M. Milano, Harvey J. Kliman et Günter P. Wagner. « An experimental test of the ovulatory homolog model of female orgasm ». Proceedings of the National Academy of Sciences 116, n^o 41 (30 septembre 2019) : 20267–73. http://dx.doi.org/10.1073/pnas.1910295116.

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The ovulatory homolog model of female orgasm posits that the neuro-endocrine mechanisms underlying female orgasm evolved from and are homologous to the mechanisms mediating copulation-induced ovulation in some mammals. This model predicts that pharmacological agents that affect human orgasm, such as fluoxetine, should also affect ovulation in animals with copulation-induced ovulation, such as rabbits. We tested this prediction by treating rabbits with daily doses of fluoxetine for 2 wk and found that fluoxetine treatment reduces the number of ovulations postcopulation by 30%. In a second experiment we tested whether this result was mediated by an effect on the brain or via peripheral serotonin functions. We treated animals with fluoxetine and induced ovulation with a single injection of human chorionic gonadotropin. In this experiment ovulation rate was nominally reduced by only 8%, which is statistically not significant. We conclude that the effect of fluoxetine on copulation-induced ovulation rate supports the ovulatory homolog model of female orgasm, suggesting that female orgasm has very deep evolutionary roots among the early eutherian mammals.

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Kishida, K., T. Nishisouzu, S. Aoki, M. Iwata, O. Dochi et H. Koyama. « 337THE ONSET AND DURATION OF OVULATION IN DAIRY COWS SUPEROVULATED FOLLOWING SYNCHRONIZATION OF FOLLICLE WAVE WITH CIDR AND ESTRADIOL BENZOATE ». Reproduction, Fertility and Development 16, n^o 2 (2004) : 288. http://dx.doi.org/10.1071/rdv16n1ab337.

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Determining the optimal time for AI of superovulated cattle is important for yielding acceptable fertilization rates. The objectives of this study were to determine the interval to onset, and the duration of ovulation in dairy cows superstimulated with FSH following synchronization of follicular wave emergence with a CIDR and estradiol benzoate (EB). Holstein (n=8) and Jersey (n=1) cows received an intravaginal progesterone insert (CIDR-B, InterAg, Hamilton, New Zealand) combined with an injection of 2mg EB at a random stage of the estrous cycle (Day 0). Superstimulatory treatments were initiated on Day 6 with a total dose of 24 or 36mg FSH (Antrin, Denka, Kawasaki, Japan) via twice-daily i.m. injections in decreasing doses for 4 days. At 72h after the first FSH injection, 30mg PGF (Pronalgon F, Pharmacia, Tsukuba, Japan) was administered, and CIDR-B were removed at 80h. Transrectal ultrasonography of ovaries was performed at 3-h intervals from 40 to 77h after the PGF injection. The numbers of ovulations were counted as previously described (Purwantara et al. 1994 Anim. Reprod. Sci. 37, 1–5). All detected follicles were counted and classified as small, medium, or large (diameter 2–4mm, 5–9mm, or ≥10mm, respectively). The number of ovulations recorded after each scanning was defined as the change in the number of large- and medium-sized follicles observed since the previous scanning. Data were analyzed using ANOVA. Results are presented in Table 1. There were two patterns of ovulations: one was a concentrated pattern of ovulations (ovulatory period <10h); the other was a prolonged pattern of ovulations (ovulatory period >10h). In cows with a high superovulatory response (≥14 ovulations), the onset of ovulation was earlier (P<0.05) and the duration of the ovulatory period was longer (P<0.05) than in cows with lower (≤8 ovulations) responses. In conclusion, concentrated and prolonged ovulation patterns were seen in dairy cows superstimulated after synchronization of the follicle wave with a CIDR and EB. In cows with a large number of follicles, the onset of ovulation tended to be earlier and the duration of the ovulatory period longer than in cows with fewer follicles. Table 1 The onset and duration of ovulation in dairy cows superstimulated following synchronization of the follicle wave with a CIDR and EB

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Luque, A., T. N. Barry, W. C. McNabb, P. D. Kemp et M. F. McDonald. « The effect of grazing Lotus corniculatus during late summer - autumn on reproductive efficiency and wool production in ewes ». Australian Journal of Agricultural Research 51, n^o 3 (2000) : 385. http://dx.doi.org/10.1071/ar99078.

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A grazing experiment was conducted at Massey University (Palmerston North, New Zealand) over 80 days in the late summer–autumn of 1998 (9 February–29 April). Reproductive performance and wool growth of ewes grazing on Lotus corniculatus (birdsfoot trefoil) were compared with those of ewes grazing perennial ryegrass–white clover pasture. A rotational grazing system with 210 mixed-age dry ewes (59.80.9 kg/ewe) was used, with 80 ewes grazing pasture [1 g of condensed tannin (CT) per kg dry matter (DM)] and 130 ewes grazing L. corniculatus (24 g CT/kg DM). Half of the ewes grazing L. corniculatus were supplemented orally, twice daily, with polyethylene glycol (PEG; MW, 3500) to inactivate the CTs. The effect of forage species and PEG supplementation on voluntary feed intake (VFI), reproductive performance (as measured by ovulation rate), and wool production was measured during 4 synchronised oestrous cycles. The ewes were restricted to maintenance feeding during the first 10 days of each oestrous cycle and then increased to ad libitum for the 6 days leading up to and including ovulation. In vitro organic matter digestibility in the selected diet was higher for lotus than for pasture (0.80 v. 0.76), with L. corniculatus containing less nitrogen than pasture (36.5 v. 40.8 g/kg organic matter). Ewes grazing on L. corniculatus produced 11% more wool and had an ovulation rate up to 14% higher than ewes grazing pasture, with neither parameter being affected by PEG supplementation. Higher mean ovulation rates of ewes grazing L. corniculatus were due to increases in fecundity (multiple ovulations/ovulating ewe; P < 0.05), with no effect on ewes cycling/ewes mated. Three cycles of grazing on L. corniculatus were required to achieve the maximum response in multiple ovulation, but most of this was achieved after 2 cycles. As the VFI of ewes grazing on L. corniculatus was not greater than that of ewes grazing pasture, the greater wool production and higher ovulation rate of ewes grazing this forage was due to improved efficiency of feed utilisation. It was concluded that feeding ewes L. corniculatus increased the efficiency of both reproduction and wool production without increasing VFI.

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Santos-Jimenez, Zurisaday, César A. Meza-Herrera, Guadalupe Calderon-Leyva, Paula Martinez-Ros, Juan M. Guillen-Muñoz et Antonio Gonzalez-Bulnes. « Efficiency of hCG for Inducing Resumption of Ovarian Cyclicity and Synchronized Ovulations during the Seasonal Anestrous in Sheep ». Animals 11, n^o 11 (5 novembre 2021) : 3159. http://dx.doi.org/10.3390/ani11113159.

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This research aimed to evaluate whether the administration of hCG at the time of removal of a progesterone device may be effective at inducing estrus and ovulations in sheep during the natural seasonal anestrous, by comparing reproductive outputs (induction and duration of estrus, follicle development, ovulation, ovulation rate, and pregnancy rates) in ewes treated with eCG or only saline solution at the time of CIDR removal. Whereas results demonstrated no response in the control non-treated group, the largest rate of narrowly synchronized estrus signs and ovulations occurred in the eCG-group. The administration of hCG was effective at inducing estrus, promote follicular growth and a delayed yet significant ovulation (>84%) on day 10 after CIDR removal; moreover, an increased embryonic implantation rate was also observed. Moreover, if the hCG ewes remain exposed to active males for some days, said strategy could be adopted, aiming to induce pregnancies by natural mating in a short period of time.

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KIRKWOOD, R. N., et P. A. THACKER. « FAILURE OF AN INDUCED OVULATION DURING LACTATION TO IMPROVE SOW OR LITTER PERFORMANCE ». Canadian Journal of Animal Science 70, n^o 1 (1 mars 1990) : 135–38. http://dx.doi.org/10.4141/cjas90-015.

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To test the effects of elevated blood progesterone on sow and litter performance, sixty-four, mixed parity Yorkshire × Landrace sows were allocated to be induced to ovulate during lactation (n = 34) or to serve as controls (n = 30). Ovulation was induced by an intramuscular injection of 1000 IU PMSG at 10 d and 500 IU hCG at 13 d of lactation. During lactation, sows were fed ad libitum a diet formulated to provide 13.1 MJ DE kg−1 and 16% crude protein while their feed intakes were recorded weekly. Piglets were weaned at 28–31 d of age. Of the 34 sows administered gonadotrophins, 19(56%) ovulated as indicated by elevated serum progesterone concentrations measured on days 20 and 28 of lactation. There was no effect (P > 0.1) of ovulation during lactation on sow feed intake, weight loss or backfat loss (5.5 vs. 5.4 kg d−1; 20.3 vs. 15.4 kg and 2.3 vs. 1.7 mm for ovulating and control sows, respectively). Similarly, there was no effect (P > 0.1) of ovulation during lactation on piglet weight gain from 14 to 28 d of age (3.1 vs. 3.1 kg) or on piglet preweaning survival (91.0 vs. 94.5% for ovulating and control litters, respectively). Sows ovulating during lactation had longer weaning to estrus intervals (9.4 vs. 5.4 d; P < 0.01). It may be concluded that ovulation and an elevated serum progesterone concentration in the latter half of lactation will not influence sow or litter performance but may increase the interval between weaning and estrus. Key words: Sows, ovulation, lactation, appetite, reproduction

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Shaaban, Mamdouh M., Kathy I. Kennedy, Gamal H. Sayed, Sharaf A. Ghaneimah et Aly M. Abdel-Aleem. « The recovery of fertility during breast-feeding in Assiut, Egypt ». Journal of Biosocial Science 22, n^o 1 (janvier 1990) : 19–32. http://dx.doi.org/10.1017/s0021932000018344.

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SummaryA longitudinal study of twenty-six breast-feeding and twelve non-breast-feeding postpartum women was conducted in Assiut, Egypt in order to determine the time that ovulation resumed after childbirth, and the effect of breast-feeding frequency on the period of lactational anovulation. Breastfeeding women experienced the onset of follicular development, vaginal bleeding, ovulation and pregnancy significantly later than women who did not breast-feed. Ovulatory and non-ovulatory breast-feeders reported similar frequencies of breast-feeding episodes. The introduction of dietary supplements commonly preceded ovulation. An algorithm using three simple variables observable to the breast-feeding mother was found to predict up to 100% of the first ovulations. All breast-feeding women who did not give supplements and did not have a vaginal bleeding episode by 6 months postpartum were anovular by strict criteria for ovulation. Ovulation did not precede bleeding or supplementation in the women who experienced these events before 6 months, yielding a highly effective formula for preventing unplanned pregnancy by the informed use of breast-feeding.

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Ginther, O. J. « Selection of side of ovulation by intraovarianism in Bos taurus heifers† ». Biology of Reproduction 103, n^o 4 (13 juillet 2020) : 711–16. http://dx.doi.org/10.1093/biolre/ioaa118.

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Abstract Intraovarianism refers to mechanisms within an ovary that affect the local follicle and luteal dynamics and is well-represented in heifers by greater frequency of ovulation from the right ovary (RO) than the left ovary (LO). On average, the RO has more 6-mm follicles than the LO before one follicle is selected to deviate in diameter and become the future ovulatory follicle. Therefore, the ovulatory follicle is more frequently selected from the RO. More follicles in the RO likely develop before birth as indicated by greater weight of the RO with more 0.3- to 4.8-mm follicles in recently born calves. It has been proposed that differences in intraovarianism between sides are a consequence of differences between sides in the inherent intraovarian angioarchitecture. The frequency of the pair of ovulations at the beginning and end of 900 interovulatory intervals (IOI) was lowest for the left/left (LL) pair (16%) and higher and similar among the RR, LR, and RL pairs (28% each). The lower frequency of LO ovulation was entirely a function of the LL pair as indicated by the lower frequency of the LL than RR pairs without a difference among the RR, LR, and RL pairs. Ovulations from the opposite sides at the beginning and end of an IOI (LR and RL pairs) would not have contributed to a difference in ovulation frequency between LO and RO. In conclusion, the greater frequency of RO (56%) than LO (44%) ovulation was mathematically and functionally a direct consequence of the low frequency of the LL pair of ovulations.

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Thomas, GB, CM Oldham, RM Hoskinson, RJ Scaramuzzi et GB Martin. « Effect of Immunization against Progesterone on Oestrus, Cycle Length, Ovulation Rate, Luteal Regression and LH Secretion in the Ewe ». Australian Journal of Biological Sciences 40, n^o 3 (1987) : 307. http://dx.doi.org/10.1071/bi9870307.

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The effects of active immunization against progesterone on reproductive activity were studied in Merino ewes. Immunization against progesterone caused a shortening (P < 0'01) of the interval between ovulations from 17-18 days (controls) to between 6 and 10 days (immunized group); this was associated with a corresponding reduction in the interval between LH surges. The immunized ewes also had higher (P < O� 05) ovulation rates (1' 72) than controls (I. 25) and exhibited a reduced (P < 0'01) incidence of oestrus (26% v. 95%). Many immunized ewes continued to ovulate despite the persistence of corpora lutea from earlier ovulations which led to an accumulation on the ovaries of many corpora lutea of different ages. The frequency of LH pulses in ewes immunized against progesterone (1'8 � 0�2 pulses/4 h) was significantly (P < 0'001) higher than that of control ewes (0'3 � 0�1 pulses/4 h). This study highlights the importance of progesterone in the control of oestrus, ovulation, ovulation rate, luteal regression and the secretion of LH in the ewe.

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Targońska, Katarzyna, Dariusz Kucharczyk, Daniel Żarski, Beata Cejko, Sławomir Krejszeff, Krzysztof Kupren, Radosław Król, Katarzyna Dryl, Radosław Kowalski et Jan Glogowski. « Artificial reproduction of wild and cultured barbel (Barbus barbus, Cyprinidae) under controlled conditions ». Acta Veterinaria Hungarica 59, n^o 3 (1 septembre 2011) : 363–72. http://dx.doi.org/10.1556/avet.2011.021.

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The aim of this work was to compare the effects of controlled reproduction of cultured and wild common barbel, Barbus barbus (L.). Preparations containing different GnRH analogues and dopamine receptor antagonists (Ovopel, Ovaprim) as well as human chorionic gonadotropin (hCG) (in the case of cultured fish) were applied and their influence on ovulation, spermiation and quality of gametes obtained was determined. No differences in the qualitative or quantitative parameters of semen were found between fish stimulated with different hormonal preparations and those not receiving hormonal stimulation. The high suitability of Ovaprim for ovulation induction in (cultured and wild) barbel was confirmed. The highest synchronisation of ovulation was obtained after the application of Ovopel (18 ± 3 h), but the best results of controlled reproduction (expressed as the percentage of ovulations and survival of embryos) were obtained by applying Ovaprim (83.2 ± 4.1). A significantly higher percentage of ovulation was obtained in cultured fish (80–90%) than in wild fish (< 25%).

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Failing, K., A. Wehrend et S. Röskes. « Sonographische Darstellbarkeit des Corpus luteum bei der Milchkuh ». Tierärztliche Praxis Ausgabe G : Großtiere / Nutztiere 40, n^o 06 (2012) : 367–73. http://dx.doi.org/10.1055/s-0038-1623138.

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Zusammenfassung Ziel der Untersuchungen war zu überprüfen, ab welchem Zeitpunkt post ovulationem das Corpus haemorrhagicum bei der Milchkuh nach spontaner oder induzierter Ovulation mit einem mobilen Ultraschallgerät sicher dargestellt werden kann. Material und Methoden: Während drei unbeeinflusster sowie drei durch die simultane Applikation von GnRH und PGF2α an den Zyklustagen 7, 14 oder 17 post ovulationem medikamentös verkürzter Zyklen wurde bei sechs Kühen die Ovardynamik dargestellt. Dazu erfolgte eine tägliche sonographische Untersuchung der Ovarien in den unbeeinflussten Zyklen ab dem 18. Zyklustag und in den Zyklen mit Behandlung ab dem Zeitpunkt der Hormongabe. Nach der Ovulation wurden die sich anbildenden Corpora lutea alle 48 Stunden sonographisch dargestellt. Eine Bestimmung der Progesteronkonzentration fand am 1. Zyklustag, am Tag der Hormongabe und in den folgenden 5 Tagen statt, um die sonographischen Befunde durch endokrine Werte abzusichern. Ergebnisse: Ab dem 5. Tag post ovulationem ließ sich das Corpus luteum in 100% der Fälle sowohl nach spontaner als auch nach induzierter Ovulation sicher darstellen. Eine sonographisch sichtbare Verkleinerung des Gelbkörpers nach induzierter Luteolyse begann in den Zyklen mit Behandlung 1,3–1,8 Tage nach der Hormoninjektion und war nach durchschnittlich 3,7 Tagen abgeschlossen. Auf die Darstellbarkeit der Gelbkörperrückbildung hatte der Zeitpunkt der Hormoninjektion im Zyklus keinen Einfluss. In 33% der Fälle wies das Corpus luteum einen zentralen flüssigkeitsgefüllten Hohlraum auf, der sich während der Luteolyse zurückbildete. Schlussfolgerung und klinische Relevanz: Die sonographische Darstellung des Gelbkörpers ist ab dem 5. Tag post ovulationem sicher möglich. Weiterhin kann der Erfolg einer eingeleiteten Luteolyse sonographisch verifiziert werden. Somit eignet sich das Verfahren zur Erfolgskontrolle einer induzierten Ovulation.

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King, Shelby M., Tyvette S. Hilliard, Lucia Y. Wu, Randal C. Jaffe, Asgerally T. Fazleabas et Joanna E. Burdette. « The impact of ovulation on fallopian tube epithelial cells : evaluating three hypotheses connecting ovulation and serous ovarian cancer ». Endocrine-Related Cancer 18, n^o 5 (3 août 2011) : 627–42. http://dx.doi.org/10.1530/erc-11-0107.

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Ovarian cancer is the most lethal gynecological malignancy affecting American women. Current hypotheses concerning the etiology of ovarian cancer propose that a reduction in the lifetime number of ovulations decreases ovarian cancer risk. Advanced serous carcinoma shares several biomarkers with fallopian tube epithelial cells, suggesting that some forms of ovarian carcinoma may originate in the fallopian tube. Currently, the impact of ovulation on the tubal epithelium is unknown. In CD1 mice, ovulation did not increase tubal epithelial cell (TEC) proliferation as measured by bromodeoxyuridine incorporation and proliferating cell nuclear antigen staining as compared to unstimulated animals. In superovulated mice, an increase in the number of pro-inflammatory macrophages was detected in the oviduct. Ovulation also increased levels of phospho-γH2A.X in TEC, indicating that these cells were susceptible to double-strand DNA breakage following ovulation. To determine which components of ovulation contributed to DNA damage in the fallopian tube, an immortalized baboon TEC cell line and a three-dimensional organ culture system for mouse oviduct and baboon fallopian tubes were developed. TEC did not proliferate or display increased DNA damage in response to the gonadotropins or estradiol alonein vitro. Oxidative stress generated by treatment with hydrogen peroxide or macrophage-conditioned medium increased DNA damage in TEC in culture. Ovulation may impact the fallopian tube epithelium by generating DNA damage and stimulating macrophage infiltration but does not increase proliferation through gonadotropin signaling.

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Silva, Otávia Reis, Marco Roberto Bourg de Mello, Lara Nogueira Silenciato, Joaquim Esquerdo Ferreira, Samuel Rodrigues Bonamichi do Couto, Rosane Scatamburlo Lizieire Fajardo et Osvaldo De Almeida Resende. « Comparison of estradiol benzoate and cypionate in Girolando cows submitted to a timed artificial insemination ». Brazilian Journal of Veterinary Research and Animal Science 56, n^o 3 (10 octobre 2019) : e155078. http://dx.doi.org/10.11606/issn.1678-4456.bjvras.2019.155078.

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The various studies on the manipulation of the estrous cycle culminated in the development of estrous and ovulation synchronization protocols, to the point of defining an optimum moment for artificial insemination. The induction of ovulation is a primordial part for the determination of the moment of the TAI, so to study which hormones and how they behave allows a better understanding of this physiological process and, to manipulate it efficiently. The aim of the present study was to compare the use of estradiol benzoate (EB) and cypionate (ECP) as ovulation inducer in Girolando cows submitted to Timed Artificial Insemination (TAI). Ovulations of 108 Girolando cows were synchronized and the initial day of treatment, recorded as D0, which was when the animals received an intravaginal device containing 1g of progestogen and an intramuscular application (im) of 2mg of EB. After 8 days (D8), the device was removed and 500μg of cloprostenol (im) was administered to all females. Then, the animals were randomly divided into two treatments: BG Group (n = 52) and CG Group (n = 56). The CG animals received 1mg of ECP (im) as the ovulation inducer at the time of device removal, while BG Group cows received 1mg of EB (im) 24 h later (D9). TAI occurred at D10. After device removal, ultrasound evaluations were performed every 12 h up to ovulation. The following reproductive parameters were evaluated: interval from intravaginal device removal to ovulation - IDO (hours); interval from ovulation to TAI-IOT (hours); diameter of the largest follicle at intravaginal device removal (mm); maximum diameter of the DF (mm) at D10; the dominant follicle growth rate (mm/day); synchronization rate - SR (%); ovulation rate - OR (%) and PR - pregnancy rate (%). Only the ovulation rate presented a statistical difference (p<0.05). In conclusion, despite the ovulation rate difference, both estradiol esters administered were effective and presented similar pregnancy rates in Girolando cows submitted to TAI.

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Yoshioka, H., H. Matsuda, Y. Yamanouchi, Y. Aoki, K. Konishi et K. Imai. « 18 RELATIONSHIP BETWEEN MULTIPLE OVULATIONS AND CONCEPTION IN LACTATING DAIRY COWS ». Reproduction, Fertility and Development 21, n^o 1 (2009) : 109. http://dx.doi.org/10.1071/rdv21n1ab18.

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The relationship between multiple ovulations and various factors involved in conception in lactating Holstein cows was investigated in this study. A total of 53 AI cows housed in a free-stall barn were assigned to this study. They were offered a balanced TMR ad libitum during the experimental period. Cows were milked at 0830 and 1900 h. Milk yields were recorded at each milking. Estrus was detected by radiotelemetric pedometers (Yoshioka et al. 2007 Reprod. Fertil. Dev. 19, 129). The body condition score (BCS) of cows was recorded at estrus. Artificial insemination was performed according to the pedometry data. Pregnancy was diagnosed 42 days post-AI by transrectal ultrasonography. Ovulation was assessed by transrectal ultrasonography of the ovary every 3 h from the end of estrus. Ovulation time was measured from the onset of estrus to ovulation. Milk production of each cow was determined from 14 days before the day of estrus. Blood samples for estradiol-17β (E2) were collected at the peak of estrus, and for progesterone (P4), samples were collected on Days 0, 3, 6, 9, and 12 (estrus = Day 0). The E2 and P4 concentrations were measured by enzyme immunoassay. Preovulatory follicles at estrus and CL on Day 0, 3, 6, 9, and 12 were monitored by transrectal ultrasonography. The overall incidence of multiple ovulations was 28.3% (15/53). There was no difference in duration of estrus between cows with multiple ovulations and cows with single ovulations (10.2 h, n = 15 v. 9.8 h, n = 38). Ovulation time was longer for cows with multiple ovulations than that for cows with single ovulations (30.4 h, n = 10 v. 28.7 h, n = 26; P = 0.0545). In all cases of multiple ovulations, 2 follicles ovulated simultaneously. The milk production of cows with multiple ovulations was higher than that of cows with single ovulations (40.1, n = 15 v. 36.2 kg d–1, n = 38; P = 0.0515); however, BCS showed the opposite results (2.86, n = 15 v. 3.13, n = 38; P < 0.05). There was a significant inverse correlation between milk production and BCS in cows with multiple ovulations (r = –0.768; P < 0.01). The E2 concentrations showed no difference between cows with multiple and single ovulations (9.6 pg mL–1, n = 8 v. 8.2 pg mL–1, n = 23). The diameters of preovulatory dominant follicles and secondary follicles at estrus in cows with multiple ovulations were significantly smaller than those in cows with single ovulations (18.2 and 14.2 mm, n = 14 v. 19.9 mm, n = 38, respectively; P < 0.05). Cows with multiple ovulations showed a significantly higher P4 concentration and a larger CL than those with single ovulations from Day 3 to 12. The conception rate for AI was significantly higher for cows with multiple ovulations than for cows with single ovulations (73.3%, n = 15 v. 36.2%, n = 38; P < 0.05). Our results showed that high conception rates, high levels of milk production, and low BCS were associated with multiple ovulations.

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Khaiseb, P. Clemens, Penelope A. R. Hawken et Graeme B. Martin. « Interactions between Nutrition and the “Ram Effect” in the Control of Ovarian Function in the Merino Ewe ». Animals 12, n^o 3 (2 février 2022) : 362. http://dx.doi.org/10.3390/ani12030362.

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We tested whether short-term nutritional supplementation (500 g lupin grain per head daily) would affect the response of ewes to the ram effect. Experiment 1 (end of non-breeding season): ewes were supplemented for either Days −6 to −1 relative to ram introduction (n = 24) or for 12 days after ram introduction (Days 11 to 22 of the ram-induced cycle; n = 29). Controls (n = 30) were not supplemented. Across all groups, 94–100% of ewes ovulated. Supplementation before ram introduction did not affect ovulation rate at the ram-induced ovulation but increased it during the ram-induced cycle (Control 1.37; supplemented 1.66; p < 0.05). Experiment 2 (the middle of non-breeding season): the supplement was fed for Days −5 to −1 relative to ram introduction. Again, supplementation did not increase number ovulating (Control 16/29; Supplemented 10/29) but it did increase ovulation rate at the ram-induced ovulation (Control 1.31; Supplemented 1.68; p < 0.05). In neither experiment did supplementation affect the frequency of short cycles. Supplementation before ram introduction did not improve the percentage of ewes ovulating or reduce the frequency of short cycles (so will not improve the synchrony of lambing). However, supplementation after ram introduction can increase prolificacy.

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Dupuis, Lisa, Yasmin Schuermann, Tamara Cohen, Dayananda Siddappa, Anitha Kalaiselvanraja, Melissa Pansera, Vilceu Bordignon et Raj Duggavathi. « Role of leptin receptors in granulosa cells during ovulation ». REPRODUCTION 147, n^o 2 (février 2014) : 221–29. http://dx.doi.org/10.1530/rep-13-0356.

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Leptin is an important hormone influencing reproductive function. However, the mechanisms underpinning the role of leptin in the regulation of reproduction remain to be completely deciphered. In this study, our objective is to understand the mechanisms regulating the expression of leptin receptor (Lepr) and its role in ovarian granulosa cells during ovulation. First, granulosa cells were collected from superovulated mice to profile mRNA expression of Lepr isoforms (LeprA and LeprB) throughout follicular development. Expression of LeprA and LeprB was dramatically induced in the granulosa cells of ovulating follicles at 4 h after human chorionic gonadotropin (hCG) treatment. Relative abundance of both mRNA and protein of CCAAT/enhancer-binding protein β (Cebpβ) increased in granulosa cells from 1 to 7 h post-hCG. Furthermore, chromatin immunoprecipitation assay confirmed the recruitment of Cebpβ to Lepr promoter. Thus, hCG-induced transcription of Lepr appears to be regulated by Cebpβ, which led us to hypothesise that Lepr may play a role during ovulation. To test this hypothesis, we used a recently developed pegylated superactive mouse leptin antagonist (PEG-SMLA) to inhibit Lepr signalling during ovulation. I.p. administration of PEG-SMLA (10 μg/g) to superovulated mice reduced ovulation rate by 65% compared with control treatment. Although the maturation stage of the ovulated oocytes remained unaltered, ovulation genes Ptgs2 and Has2 were downregulated in PEG-SMLA-treated mice compared with control mice. These results demonstrate that Lepr is dramatically induced in the granulosa cells of ovulating follicles and this induction of Lepr expression requires the transcription factor Cebpβ. Lepr plays a critical role in the process of ovulation by regulating, at least in part, the expression of the important genes involved in the preovulatory maturation of follicles.

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Zambrini, F. N., E. P. Costa, J. H. Bruschi, J. M. G. Souza, L. S. Amorim et J. F. Fonseca. « 449 EFFECTS OF HORMONAL ADMINISTRATION IN TWO DIFFERENT SHIFTS AND OVULATORY DYNAMICS IN NONBREEDING SEASON ON TOGGENBURG GOATS ». Reproduction, Fertility and Development 22, n^o 1 (2010) : 381. http://dx.doi.org/10.1071/rdv22n1ab449.

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Assisted reproduction has been used to optimize reproduction in goats. Ultrasound technology has resulted in a definite gain of knowledge in terms of ovulation time. The aim of this study was to evaluate if the shift (morning or afternoon) of hormonal administration affects different reproductive parameters. This study was conducted from October to December (nonbreeding season) of 2005, in Piau/MG (21°35′S latitude and 43° 15′W longitude), Brazil. Eighteen nulliparous (n = 9) or pluriparous (n = 9) Toggenburg goats were assigned equally according to body weight and condition score into two treatments. Animals received intravaginal sponges (60 mg of MAP, Progespon®, Syntex, Buenos Aires, Argentina) for 6 days plus 37.5 (igof cloprostenol (Prolise®, ARSA S.R.L., Buenos Aires, Argentina) latero-vulvar and 200 IUeCG (Novormon® 5000, Syntex) i.m. 48 h before sponge removal. Procedures were done early in the morning for T1 (10 h) and later in afternoon for T2 (17 h). Goats were monitored twice daily to identify estrous onset and its duration. After sponge removal, ultrasound evaluations were performed every 8 h until ovulation to determine the time, number of ovulations, and ovulatory follicle diameters (5-MHz transducer; Aloka, SSD 500®, Tokyo, Japan). Statistical analyses were performed using all tests at the 95% confidence interval with a SAEG® program (Funarbe, Viçosa, Brazil). The results are presented as mean ± SD. The interval (h) from sponge removal to estrous onset was 30.7 ± 10.6 (T1) and 34.3 ± 17.6 (T2), whereas its duration was 33.3 ± 22.3 (T1) and 34.3 ± 22.4 (T2) (P > 0.05). The interval (h) from sponge removal to ovulation was 54.4 ± 10.2 (T1) and 53.4 ± 12.3 (T2) (P > 0.05). Also, the interval (h) from estrous onset to ovulation was 26.8 ± 8.7 (T1) and 18.1 ± 26.3 (T2). No difference (P > 0.05) was observed in the number of ovulations forT1 (1.89 ± 0.93) or T2 (1.89 ± 0.60). The diameter of the ovulatory follicle (mm) was similar (P > 0.05) for T1 (8.4 ± 1.28) and T2 (7.36 ± 1.15) (P > 0.05). A negative correlation was detected between the interval to estrous onset and diameter of the largest follicle (r = -0.41; P < 0.05), as well as between the interval to estrous onset and the interval from estrus to ovulation (r= -0.73; P < 0.001). A positive correlation was registered between the interval from estrus to ovulation and diameter of the largest follicle (r = 0.65; P < 0.001) and also between the interval from sponge removal to ovulation and diameter of the largest follicle (r = 0.51; P < 0.005) that was evident, indicating that follicles get larger with time. Finally, a negative correlation (r = -0.88; P < 0.05) was obtained between number of ovulations and average diameters of ovulated follicles. These data suggest that Toggenburg goats have a synchronization of ovulation when receiving progestagen short-term protocols in the nonbreeding season, independent of the hormonal dispensing shift. Financial support: Embrapa Goats and Sheep, Tecnopec, Fapemig, CNPq.

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Duggal, Priya S., Kylie H. Van der Hoek, Clyde R. Milner, Natalie K. Ryan, David T. Armstrong, Denis A. Magoffin et Robert J. Norman. « The in Vivo and in Vitro Effects of Exogenous Leptin on Ovulation in the Rat* ». Endocrinology 141, n^o 6 (1 juin 2000) : 1971–76. http://dx.doi.org/10.1210/endo.141.6.7509.

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Abstract Leptin, a hormonal product of the Lep gene, is expressed by adipocytes and is thought to play a role in regulating food intake and reproduction. The leptin protein has been localized in many reproductive tissues, including the ovary. Several publications indicate that the ovary is directly affected by leptin and that leptin may be a factor linking obesity and reproductive dysfunction. In this study, the effect of systemic leptin administration on ovulation in the rat ovary, both in vivo and in vitro, was investigated. Ip administration of leptin (30 μg at 3 hourly intervals for 15 h) to immature gonadotropin-primed rats caused a decline in ovulation in vivo, from 15.9 ± 2.0 oocytes in the control animals to 5.3 ± 1.6 oocytes in the leptin-treated animals (P < 0.001). Plasma progesterone and estradiol levels were analyzed immediately before ovulation, and neither was altered significantly in animals receiving the leptin treatment. Food consumption and body weight decreased following leptin treatment; however, a loss in body weight alone (pair-fed controls) was insufficient to explain the decrease in ovulation observed in the leptin-treated animals. In vitro perfusion of FSH-primed whole ovaries showed that treatment with leptin in combination with LH significantly decreased ovulations from 5.7 ± 1.6 per ovary perfused with LH alone to 1.3 ± 0.6 in those with LH and 1 μg/ml leptin (P < 0.05). Progesterone and estradiol levels in the samples taken during the perfusion period were unaffected by leptin treatment. In summary, leptin administration resulted in fewer ovulations, both in vivo and in vitro, but did not influence steroid levels. Systemic leptin administration at these doses can therefore inhibit ovulation, a process that occurs through a direct effect on the ovary.

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Senatore, E. M., W. R. Butler et P. A. Oltenacu. « Relationships between energy balance and post-partum ovarian activity and fertility in first lactation dairy cows ». Animal Science 62, n^o 1 (février 1996) : 17–23. http://dx.doi.org/10.1017/s1357729800014260.

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AbstractForty primiparous Holstein dairy cows were monitored from calving through 100 days in milk to evaluate the effect of energy balance in the early post-partum period on subsequent fertility. The post-partum interval to first ovulation (R2 = 0·41; P < 0·005) was lengthened by greater negative energy balance, and reduced by greater body weight at parturition or decreased body-weight loss during the experimental period. Luteal activity (R2 = 0·58; P < 0·0001), measured by plasma progesterone area under curve, was increased in the first cycle post partum by a shorter interval to first ovulation, improved energy balance during the 1st week of lactation and by decreased body-weight loss. Pregnancy status following first artificial insemination was related positively to the number of ovulations before insemination, improved energy balance during the 1st month post partum, fewer days to first ovulation and greater body weight at calving. These data suggest that energy balance and body weight are important in determining the post-partum interval to first ovulation and the subsequent fertility of first lactation dairy cotes.

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Li, Tao, Xuehua Ren, Tianjiao Li, Lian Yu, Mingming Teng, Yi Zheng et Anmin Lei. « Low-Dose Sodium Salicylate Promotes Ovulation by Regulating Steroids via CYP17A1 ». International Journal of Molecular Sciences 24, n^o 3 (30 janvier 2023) : 2579. http://dx.doi.org/10.3390/ijms24032579.

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To meet the current demand of assisted reproduction and animal breeding via superovulation and reduce the impact of hormone drugs, it is necessary to develop new superovulation drugs. This study examined the role of inflammation and steroids in ovulation. Sodium salicylate can regulate inflammation and steroids. However, the effect of sodium salicylate on ovulation has not been studied. In this study, mice were intraperitoneally injected with different concentrations of sodium salicylate for four consecutive days. The effects of sodium salicylate on oocyte quality and on the number of ovulations were examined, and these effects were compared with those of pregnant horse serum gonadotropin (PMSG)/follicle-stimulating hormone (FSH) treatment. We found that low-dose sodium salicylate increased the levels of ovulation hormones and inflammation by promoting the expression of CYP17A1. Sodium salicylate had the same effect as the commonly used superovulation drug PMSG/FSH and reduced the histone methylation level. Sodium salicylate can promote ovulation in mice and Awang sheep. It can greatly decrease the use of hormone drugs, reduce breeding costs and physical impacts, and can thus be used for livestock breeding.

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Relton, C. E., N. C. Bennett et K. Medger. « The mode of ovulation in the Namaqua rock mouse, Micaelamys namaquensis ». Canadian Journal of Zoology 91, n^o 11 (novembre 2013) : 829–36. http://dx.doi.org/10.1139/cjz-2013-0145.

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The pattern of ovulation in mammals is generally considered to be either spontaneous or induced by copulation, with environmental and social factors playing a key role in determining the specific mode of ovulation that would maximize the reproductive potential of the species. This study aims to determine whether the Namaqua rock mouse (Micaelamys namaquensis (A. Smith, 1834)) is a spontaneous or induced ovulator. Females were divided into three treatments differing in the degree of contact with a male. Namely, seven control females had no contact with a male; a further seven separated females had only chemical, auditory, and visual contact with a male; whereas six females had intermittent periods of full contact with a vasectomized male. Ovarian size, follicular development, and plasma progesterone concentrations were compared between the three treatments. Penile morphology was also investigated. Corpora lutea were found in all three treatments and the penis was smooth without any ridges or spikes, indicating that M. namaquensis is a spontaneous ovulator. Interestingly, however, the presence of a male (physical as well as just visual and olfactory) positively affected ovarian size, ovulation, and plasma progesterone concentrations. This signifies that although M. namaquensis ovulates spontaneously, male contact significantly influences ovulation rate and ultimately reproductive success.

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Pinna, A. E., F. Z. Brandão, A. S. Cavalcanti, A. M. Borges, J. M. G. Souza et J. F. Fonseca. « Reproductive parameters of Santa Inês ewes submitted to short-term treatment with re-used progesterone devices ». Arquivo Brasileiro de Medicina Veterinária e Zootecnia 64, n^o 2 (avril 2012) : 333–40. http://dx.doi.org/10.1590/s0102-09352012000200012.

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The aim of this study was to verify the efficacy of reusing intravaginal progesterone (P4) devices on the reproductive parameters in Santa Inês ewes. Females received intravaginal P4 devices for their first, second or third use for five days plus 300 IU eCG IM and 5mg dinoprost laterovulvar 24h before device removal. Blood was collected at different moments. Transrectal ultrasonography was performed from device removal to ovulation. Part of the ewes were submitted to artificial insemination by laparoscopy (IAL - n=55) with fresh semen, whereas the rest were bred by fertile rams (n=41). On the initial 18 h, ewes that received devices for the first time showed higher P4 concentrations (5.1±1.8 vs 3.5±1.4 vs 2.4±1.1 - P<0.05). However, after the first 48h no difference was observed among all treatments and P4 supraluteal concentrations were detected in all ewes upon device removal. Estrous response, interval from device removal to estrus, rate of ovulating animals, number of ovulations, time from device removal to ovulation and average conception rates after IAL or natural mating were similar among all 3 groups. Intravaginal progesterone devices can be used up to three times without altering reproductive parameters in Santa Inês ewes.

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Oliveira, Maria Emilia Franco, Mabel Freitas Cordeiro, Roberta Machado Ferreira, Samuel Figueirêdo Souza, Juliana Souza Pinto Pieroni, Luiz Fernando de Souza Rodrigues, Jeferson Ferreira da Fonseca et Wilter Ricardo Russiano Vicente. « Does supplemental LH changes rate and time to ovulation and embryo yield in Santa Ines ewes treated for superovulation with FSH plus eCG ? » Ciência Rural 42, n^o 6 (juin 2012) : 1077–82. http://dx.doi.org/10.1590/s0103-84782012000600021.

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The objective was to evaluate if supplemental LH given at the end of FSH treatment would synchronize the time of ovulation and increase the ovulation rate and embryo yield in Santa Ines ewes. Twenty superovulatory (SOV) programs were accomplished in cross-over design (60d interval). On D0, a CIDR device was inserted, and the device was replaced with a new one 7 days later, when 37.5µg of d-cloprostenol was administered. On D12, we started the SOV treatment, administering 256mg of pFSH 8 times, 12h apart. On D14, the CIDR was removed, and 200IU of eCG and 37.5µg of d-cloprostenol were administered. On D15, the ewes were allocated into one of two groups, a Control group (n=10) that received no supplemental LH and a LH group (n=10) treated with 7.5mg of LH 24h after CIDR removal. Artificial inseminations (AI) were performed 42 and 48h after CIDR removal. The ovarian structures were evaluated by laparoscopy immediately before each AI and 5 days later (D21) when the embryos were collected. The LH ewes ovulated more frequently (P=0.05) before 42h than between 42 and 48h. Treatment with LH tended to increase the frequency of CL and to decrease the anovulatory follicles (P=0.08). The supplemental LH increased the frequency of ewes with a high SOV response (≥11 CL; P=0.05). In conclusion, supplemental LH increased the frequency of ewes with high SOV response and ovulating prior to 42h, however, there was no synchrony between ovulations. The supplemental LH also decreased the frequency of anovulatory follicles, although the ovulation rate and embryo yield were unaffected.

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Panigrahi, Madhuri, et Santosh K. Panda. « Effect of ovulation on serum cholesterol in women of reproductive age group ». International Journal of Reproduction, Contraception, Obstetrics and Gynecology 7, n^o 2 (23 janvier 2018) : 424. http://dx.doi.org/10.18203/2320-1770.ijrcog20180036.

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Background: Reproduction and contraception is mostly central around ovulation. The sex hormones undergo changes in levels with ovulation. They also play an important role in cholesterol metabolism, especially oestrogen. Aim of our study was to find out changes in serum cholesterol before and after ovulation in women of reproductive age.Methods: In present study 70 women of reproductive age group (15-49years) were recruited. Serum cholesterol was measured around time of ovulation.Results: It was found that, during the follicular phase there was a significant increase in total cholesterol and LDL-C concentrations compared to post ovulatory phase. During the ovulatory phase there was a decrease in total cholesterol and increase in HDL-C compared to follicular phase. VLDL levels showed increasing trend from follicular to post ovulatory phase.Conclusions: Ovulation improves cardiovascular risk factors which may account of the decreased risk of cardiovascular diseases among ovulating women. And secondly, the menstrual cycle phase should be taken into account when evaluating cholesterol levels among reproductive age group women.

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Gillis, D. J., B. A. McKeown et D. E. Hay. « Physiological and Histological Aspects of Late Oocyte Provisioning, Ovulation, and Fertilization in Pacific Herring (Clupea harengus pallasi) ». Canadian Journal of Fisheries and Aquatic Sciences 47, n^o 8 (1 août 1990) : 1505–12. http://dx.doi.org/10.1139/f90-168.

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Late vitellogenic, ovulating, and ovulated Pacific herring oocytes were examined histologically and histochemically in order to understand these fine-scale processes and to evaluate egg maturation timing test criteria for use in resource management. Late vitellogenic events were investigated using an alkali-labile protein phosphorus (ALPP) assay of serum, liver, and gonad tissue. Serum levels were constant in males but declined in females. Ovarian levels declined (110 to 15 mg/L) during ovulation. Hepato-somatic indices were constant in males but declined in females (1.6 to 0.9%) during ovulation. The abundance of electron-lucent hepatocytes in female livers compared with males, their synthetic and secretory structures, and their reversion during ovulation suggest these cells as vitellogenin synthetic locations. During population ovulation, the gonosomatic index for females and males increased from 15–27%, and 15–23% respectively. Eggs hydrated from 67–76% during ovulation, and secondarily to 83% after fertilization. Unfertilized eggs dehydrated to 74% water. Alkaline phosphatase was localized in follicular granulosa and thecal cells suggesting these as locations of vitellogenin dephosphorylation. The test criteria; hepato-somatic index, lucent hepatocyte ratios, gonadosomatic index, and egg moisture are problematic but ovarian ALPP determination appears promising.

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Horáčková, Eliška, Miroslava Mráčková, Michal Vyvial, Šárka Krisová et Markéta Sedlinská. « The effect of hCG, GnRH and PGF2α analogue cloprostenol on the oestrus cycle in jennies ». Acta Veterinaria Brno 88, n^o 3 (2019) : 271–75. http://dx.doi.org/10.2754/avb201988030271.

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The objectives of this study were twofold. Firstly, the present study was designed to examine susceptibility of the corpus luteum (CL) in early diestrus in jennies; and secondly, to investigate the effect of two commonly used hormonal agents in horses on the induction of ovulation in jennies. The oestrus cycles of eleven jennies were monitored by ultrasound every day. When the dominant follicle reached a diameter of 30 mm, the jennies were treated by intramuscular administration of gonadotropin-releasing hormone agonist lecirelin (GnRH, 50 µg pro toto) in the first oestrus cycle, and human chorionic gonadotropin (hCG, 1500 IU pro toto) intramuscularly in the second oestrus cycle. Prostaglandin F2α analogue cloprostenolum (PGF2α, 0.125 mg pro toto) was administered intramuscularly 2 days after the first ovulation and the interovulatory interval was monitored. This study showed that intramuscular administration of 50 µg of GnRH agonist lecirelin resulted in ovulation within 48 h in 73% of treated jennies. Intramuscular administration 1500 IU of hCG was found to be poorly effective to induce ovulation, with 36% of animals ovulating within 48 h. Intramuscular administration of PGF2α analogue cloprostenol 2 days after ovulation was unsuccessful in attempting to shorten the interovulatory interval in donkeys.

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Fitzgerald, Barry P., Steven L. Meyer, Karen J. Affleck et Pamela J. Silvia. « Effect of constant administration of a gonadotropin-releasing hormone agonist on reproductive activity in mares : Induction of ovulation during seasonal anestrus ». American Journal of Veterinary Research 54, n^o 10 (1 octobre 1993) : 1735–45. http://dx.doi.org/10.2460/ajvr.1993.54.10.1735.

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Summary The potential of a gonadotropin-releasing hormone (GnRH) agonist (goserelin acetate), delivered constantly for 28 days via a subcutaneous depot, to induce ovulation in seasonally anestrous mares, was investigated. Two experiments were conducted, in which a range of doses (30 to 240 µg/mare/d) was examined. Mares were selected on the basis of lack of substantial follicular development (follicle diameter < 20 mm determined ultrasonically) and low serum concentrations of luteinizing hormone (lh) and progesterone. Constant administration of the GnRH agonist-induced ovulation in anestrous mares, but a dose-response relation was not observed. Furthermore, with identical doses tested in consecutive or alternate years, considerable variation was observed in the ovulatory response. In general, ovulation in all treated mares was accompanied by increased circulating concentrations of lh and a decrease in follicle-stimulating hormone values. Ovulation was preceded by an increase in estradiol and lh concentrations. In mares in which ovulation did not occur, concentration of lh increased during agonist treatment, whereas that of follicle-stimulating hormone either increased or did not change. It was concluded that constant administration of GnRH agonists may induce ovulation in mares during seasonal anestrus; however, percentage of mares ovulating and the lack of reproducibility of effect indicate that this approach is inappropriate for use as a reliable method to manipulate breeding activity in commercial broodmares.

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Palhao, M. P., M. A. Beg, M. T. Rodrigues, R. R. Araújo, J. H. M. Viana, A. M. Borges et O. J. Ginther. « 219 FOLLICLE AND HORMONE DYNAMICS IN SINGLE- v. DOUBLE-OVULATING HEIFERS ». Reproduction, Fertility and Development 22, n^o 1 (2010) : 267. http://dx.doi.org/10.1071/rdv22n1ab219.

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The present experiment used the Day 4 ablation model for increasing the incidence of double ovulations in heifers. The objective was to compare follicle growth and plasma hormone concentrations associated with single v. double ovulations. Follicles ≥5 mm were ablated at 4 days post-ovulation to induce a prominent FSH surge and a new follicular wave, and 2 injections of PGF2 (12 h apart) were given 2 days later (Day 6) to favor ovulation. Beginning on Day 5, the 3 largest follicles of the induced wave were scanned twice a day until 36 h after the next ovulation. Blood samples were taken at 6-h intervals starting when the largest follicle reached ≥8.0 mm (expected deviation at 8.5 mm; Ginther et al. 1996) and continued until 36 h after the next ovulation. Concentrations of LH and FSH were measured by validated RIA for cattle (LH measured by Ginther et al. 1999; FSH measured by Adams et al. 1992) and concentrations of oestradiol measured by a commercially available RIA kit (Siddiqui et al. 2009). From a total of 31 heifers, 16 (52%) or 15 (48%) developed a single or more than 1 dominant (≥ 10 mm) follicle in the follicular wave after ablation, respectively. For heifers with 2 dominant follicles, the second-largest follicle ovulated in 9 (60%) heifers and the overall double ovulation rate was 29% (9/31). Follicle diameters and plasma hormone concentrations were compared between single ovulators (n = 12) and double ovulators (n = 8). Diameter of the preovulatory follicles did not increase between the LH peak and ovulation in either the single or double ovulations. In double ovulators, the interval from follicle deviation to the peak of the preovulatory LH surge was shorter (1.9 ± 0.2 days v. 2.5 ± 0.2 days; P < 0.02) and the diameter of the largest preovulatory follicle was smaller (12.2 ± 0.5 mm v. 13.3 ± 0.3 mm; P < 0.02) than in single ovulators, respectively. The LH concentrations of the preovulatory surge did not differ between single and double ovulators for 24 h on each side of the peak (main effect of hour only; P < 0.0001). When data were normalized to the LH peak, the peak of the preovulatory FSH and estradiol surges occurred in synchrony with the peak of LH surge for both groups. A group effect (P < 0.0001) for FSH resulted from a lower concentration averaged over hours in double ovulators. Estradiol showed a group by hour interaction (P < 0.008), reflecting greater concentrations in the double ovulators before and at peak. In conclusion, an increased Supported by the Eutheria Foundation, Cross Plains, WI, USA. Submission supported by FAPEMIG.

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Pennington, P. M., L. R. Gentry, C. E. Pope, R. A. MacLean, D. L. Paccamonti, B. L. Dresser, K. R. Bondioli, R. A. Godke et G. Wirtu. « 164 CHARACTERIZATION OF THE COMMON ELAND (TAUROTRAGUS ORYX) ESTROUS CYCLE ». Reproduction, Fertility and Development 21, n^o 1 (2009) : 181. http://dx.doi.org/10.1071/rdv21n1ab164.

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Three species of Tragelaphine (spiral horned) antelopes are endangered including the Eastern Bongo. Though most antelope species are represented as captive herds, a detailed characterization of their estrous cycles has not been described. In a crossover experimental design utilizing two groups of four females (n = 8), two estrus synchronization treatments were applied to each female. The treatments were: 1) PGF2∝ (Lutalyse®, 25 mg IM) repeated 11 days later and 2) administration of a progestin (altrenogest, 5 mL, 2.2% p.o.) for 7 days followed by PGF2∝ (25 mg IM) on 7th day. Blood samples were collected three days (Monday, Wednesday and Friday) per week until 2 days before expected estrus when ovaries were examined via transrectal ultrasound once daily and blood samples were collected twice daily, until the dominant follicle was absent. Blood samples were then collected three days per week until two days before the predicted subsequent natural estrus, when intensive ultrasound and blood collection was resumed. Plasma progesterone levels were determined via competitive radioimmunoassay utilizing a double antibody system from a commercially available kit (Diagnostic Systems Laboratories, Webster, TX, USA). Progesterone levels declined in an equal number of females (n = 6 or 75%) following prostaglandin injection in treatments 1 and 2, suggesting both methods to synchronize the estrous cycle or induce estrus are equally effective. Five of the eight females ovulated at least once during the study. A total of eight (25%) of the 32 possible ovulations were detected by ultrasound observation and confirmed by progesterone levels. Basal progesterone levels for the ovulating females around the days of ovulation were approximately 0.5 ng mL–1 and peaked at approximately 2 ng mL–1 during the luteal phase. Ultrasound observed ovulations occurred as frequently on the right ovary as the left. Two animals from treatment 2 ovulated during both the induced and natural cycles on alternate ovaries. An interovulatory interval of 21 days was observed and agrees with data previously reported by Durrant (1983 Zoo Biol. 2, 191–197). The average time to ovulation after PGF2∝ injection was 69 h (range 58–82 h). The average follicular size 12 to 24 h prior to ovulation was 9 and 7 mm for the induced and natural ovulations, respectively, suggesting that eland follicles ovulate at 10 mm. The described technology allows hormonal and ultrasonographic characterization of the estrous cycle in the eland antelope.

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Thompson, C. L., P. L. Whitten et M. A. Norconk. « Can male white-faced saki monkeys (Pithecia pithecia) detect female reproductive state ? » Behaviour 148, n^o 11-13 (2011) : 1310–28. http://dx.doi.org/10.1163/000579511x605227.

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Abstract For mammalian males, copulating with females during ovulation is critical to reproductive success. However male knowledge of ovulation may not always be advantageous for females, as it could hinder mate choice or promote harassment. White-faced saki monkeys live in variably monogamous and polygamous social groups and hence females may have multiple motivations to conceal ovulatory timing. White-faced sakis further show no obvious physical or behavioral signs of ovulation, although they do use scent in a variety of contexts, including sexual behavior. We collected data on three wild groups of white-faced sakis at Brownsberg Naturepark, Suriname in order to assess whether male copulations are coordinated with female ovulatory timing. We recorded all occurrences of copulations and genital inspections, and collected fecal samples from females which were radioimmunoassayed to obtain estradiol and progesterone levels. We found that males copulated throughout the female reproductive cycle, although the association between copulation and reproductive state varied between dyads. Only one male–female dyad showed significantly more copulations than expected during ovulation. However four of five dyads copulated less than expected with pregnant females, suggesting that males may be able to differentiate cycling from non-cycling females. While genital inspections were distributed randomly with regard to female reproductive state, the decision to copulate was not: males were more likely to mate with both ovulating and cycling females than with non-cycling females after genital inspection. Regardless, males were not more likely to copulate with an ovulating vs. a cycling (non-ovulating) female. These data indicate that while males may receive olfactory information on female hormonal status, they do not make entirely accurate decisions with regard to copulation timing. This inaccuracy may be due to males' inability to detect ovulation, or alternately a lack of motivation to limit copulations solely to conceptive periods. Pair familiarity and sexual experience may also play a role in copulation accuracy.

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Menkhorst, E., N. Ezard et L. Selwood. « Induction of ovulation and natural oestrous cycling in the Stripe-faced Dunnart, Sminthopsis macroura ». Reproduction 133, n^o 2 (février 2007) : 495–502. http://dx.doi.org/10.1530/rep-06-0254.

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Induced ovulation allows reproduction by otherwise infertile females, and is ideal for the captive breeding of endangered species where the population is aged or breeding is unsuccessful. A predictable time of ovulation after induction has not yet been achieved in polyovular marsupials. Ovulation was induced in Sminthopsis macroura using an initial injection of 20 IU equine serum gonadotrophin (eSG; Day 0), followed on Day 4 by either 20 IU eSG (n = 25) or 0.5 mg porcine luteinizing hormone (n = 26). I.p. hormone injection was given in the morning or early evening, and reproductive status was established prior to induction. Five non-cyclic animals began to cycle naturally following induction and one gave birth to a litter. The time of ovulation after the 1st injection (7.8 ± 0.9 days) was significantly shorter (P = 0.000) and less variable than the previous study, mimicked the timing of natural cycling, and both natural and induced animals ovulated in the early morning. In vitro oocyte movement through the oviduct, observed for the first time in a marsupial, occurred in pulses. We estimated one group of oocytes could travel the length of the oviduct in 40 min, but it was probably around 4 h. The entire ovulation time (including multiple ovulations) was estimated at 7.5 h. This study has achieved a predictable timing of ovulation after stimulation, and induced noncyclic animals to cycle naturally and give birth, providing a modified methodology for use in captive breeding programs of endangered dasyurid marsupial species with low fecundity.

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Regan, Sheena L. P., James R. McFarlane, Tim O'Shea, Nicholas Andronicos, Frank Arfuso, Arun Dharmarajan et Ghanim Almahbobi. « Flow cytometric analysis of FSHR, BMRR1B, LHR and apoptosis in granulosa cells and ovulation rate in merino sheep ». REPRODUCTION 150, n^o 2 (août 2015) : 151–63. http://dx.doi.org/10.1530/rep-14-0581.

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The aim of the present study was to determine the direct cause of the mutation-induced, increased ovulation rate in Booroola Merino (BB) sheep. Granulosa cells were removed from antral follicles before ovulation and post-ovulation from BB (n=5) and WT (n=12) Merino ewes. Direct immunofluorescence measurement of mature cell surface receptors using flow cytometry demonstrated a significant up-regulation of FSH receptor (FSHR), transforming growth factor beta type 1, bone morphogenetic protein receptor (BMPR1B), and LH receptor (LHR) in BB sheep. The increased density of FSHR and LHR provide novel evidence of a mechanism for increasing the number of follicles that are recruited during dominant follicle selection. The compounding increase in receptors with increasing follicle size maintained the multiple follicles and reduced the apoptosis, which contributed to a high ovulation rate in BB sheep. In addition, we report a mutation-independent mechanism of down-regulation to reduce receptor density of the leading dominant follicle in sheep. The suppression of receptor density coincides with the cessation of mitogenic growth and steroidogenic differentiation as part of the luteinization of the follicle. The BB mutation-induced attenuation of BMPR1B signaling led to an increased density of the FSHR and LHR and a concurrent reduction in apoptosis to increase the ovulation rate. The role of BMPs in receptor modulation is implicated in the development of multiple ovulations.

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Sharma, Akshay, Madhumeet Singh, Pravesh Kumar et Pradeep Kumar Dogra. « Investigating Post-partum Ovarian Cyclicity Following Various Treatments in Dairy Cows ». Rural Sustainability Research 41, n^o 336 (1 août 2019) : 22–25. http://dx.doi.org/10.2478/plua-2019-0004.

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Abstract The present study envisages the effect of PGF2α and antibiotic treatment on ovarian cyclic activity and regression of corpus luteum verum in post-partum dairy cows. Cows were divided into three treatment (PG8, PG25, antibiotic) and a control group. Ovarian activity was studied by examining follicular dynamics upto 42 days post-partum in which diameter of dominant follicle before first ovulation, the number of days to first ovulation and complete regression of corpus luteum verum were evaluated. Body condition score was recorded for all the cows in different groups. Also, ovulation on ovary ipsilateral or contralateral to previous gravid uterine horn was noted. On transrectal ultrasonography at a 3-day interval, dominant follicle diameter prior to ovulation was significantly higher (p<0.01) in PG8 group. The mean time required for complete regression of CL verum was not significantly (p>0.05) lower in PG8 group i.e. 24.33±1.48 days in comparison to PG25, antibiotic and control group (26.67±1.48, 29.00±1.81and 27.60±1.40 days post-partum, respectively). A subsequent ovarian activity was affected as 70.83 and 66.33% Ist and IInd ovulations occurred on the ovary contralateral to corpus luteum verum. In conclusion, contralateral ovary was more active in terms of ovulation whereas presence of corpus luteum verum had no effect on post-partum ovarian cyclic activity.

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Presicce, G. A., G. De Santis et E. M. Senatore. « 227OVARIAN FOLLICULAR DYNAMICS IN POSTPARTUM MEDITERRANEAN ITALIAN BUFFALOES ». Reproduction, Fertility and Development 16, n^o 2 (2004) : 235. http://dx.doi.org/10.1071/rdv16n1ab227.

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In cattle and buffaloes resumption of ovarian activity, as expressed by first post partum ovulation and follicle turnover leading to periodic estrus cycles and ovulations, can be affected by many factors among which uterine infections and dietary supplementation play a leading role. In addition, buffaloes are considered seasonal animals characterized by a tendency to reproduce in correspondence to a decrease of day length. This aspect may further affect their reproductive efficiency by delaying or interrupting ovarian activity if calving occurs in transitional (i.e., from end winter into beginning of spring) or unfavourable (spring-summer) periods of the year, when an increase of daylight hours occurs. The aim of this study, carried out in the months of February to May, was to understand the effect of increasing daylight hours over resumption of postpartum ovarian follicular dynamics and estrus cycles. Mixed parity Mediterranean Italian buffaloes (n=20) were monitored daily by ultrasonography from calving until first postpartum ovulation and following cycle or until 60 days if no ovulations had been recorded. Ultrasound monitoring was performed by using a 7.5MHz linear-array probe and an Aloka SSD-500 monitor. No pharmacological intervention was allowed during the course of the study and animals were kept under similar feeding and farm management conditions. All animals exhibited a mild to moderate uterine inflammation (n=13; 65%) or aspecific infection (n=7; 35%) after calving. Infections were manifested as purulent discharge and as ultrasound detection of highly echogenic debries in the uterine lumen. Only one animal retained pathological accumulation in both horns for the entire duration of the study. Among the 20 buffaloes under study, 12 (60%) exhibited postpartum ovulations, ranging from 9 to 45 days. In eight buffaloes (40%), such ovulations occurred in the ovary contralateral to the ovary bearing the gravidic CL. Following postpartum ovulations, seven buffaloes (35%) underwent a complete cycle leading to ovulation. Three of such cycles (15%) culminated with a second ovulation in the same ovary where post partum ovulations had occurred. Among the full cycles following postpartum ovulations, four of them were one-wave, with a range of 8 to 19 days, whereas the remaining three cycles were two-wave with a range of 17 to 22 days. Eight buffaloes (40%) were reported in anovulatory condition following parturition, although in four of them both ovaries displayed a typical follicle turnover. In conclusion, resumption of ovarian activity and reproductive efficiency in water buffaloes can be affected by increasing day length as evidenced by a high rate of postpartum anovulatory conditions and reduced follicle turnover.

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Ahmad, W., M. I. R. Khan, A. Murtaza, I. Mohsin, A. Riaz et K. Javed. « 121 Ovulatory response to gonadotropin-releasing hormone relative to day and diameter of dominant follicle during the first follicular wave in Beetal goats ». Reproduction, Fertility and Development 31, n^o 1 (2019) : 186. http://dx.doi.org/10.1071/rdv31n1ab121.

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In Beetal goats under subtropical conditions, ovulatory response of first-wave dominant follicle based on diameter and day of oestrous cycle is unknown to date. The objective of this study was to evaluate the ovulatory response to gonadotropin-releasing hormone (GnRH) relative to day and diameter of dominant follicle during the first follicular wave in Beetal goats. Fifty goats were synchronized using a single dose of prostaglandin F2α (75 µg; D+ cloprostenol, Fatro, Italy), and scanned every 6 hours for ovulation using a 7.5-MHz trans-rectal transducer (Honda HS: 1500, Japan). Following ovulation (Day 0), goats (n=40; 10/day) were given GnRH (25µg lecirelin, Fatro, Italy) on Days 2, 4, 6, and 8 of oestrous cycle. Follicular dynamics was monitored daily from D 0 until GnRH, and every 4 hours after GnRH until ovulation. Ovulation frequency relative to day and dominant follicular diameter was analysed by binary logistic regression, whereas diameter of dominant follicle at time of GnRH, ovulation time, time of wave emergence and growth rate of dominant follicle following GnRH were analysed by one-way ANOVA and independent sample t-test (SPSS 20, IBM Corp., Armonk, NY, USA). Eighty percent of the goats ovulated within 74.7±1.3h after prostaglandin F2α. Overall, 37% (14/38) of the goats ovulated following GnRH within 12.0±1.5h. Ovulations (%) following GnRH were higher (P=0.03) on Day 4 than 2 (60 v. 10%; i.e. 14 times higher than Day 2) and decreased gradually from Day 4 to 8 (P>0.05). Similarly, ovulations following GnRH were higher (P=0.00) in first-wave dominant follicles having diameter 6.1-7.0mm than those having less than 6.1mm (88v. 23%; i.e. 24 times higher than <6.1mm). Ovulations (%) decreased as the diameter of dominant follicle increased from 6.1-7.0mm (P>0.05). Diameters of ovulatory follicles at time of GnRH between Day 2, 4, 6, and 8 were not different (P>0.05). Regardless of day of GnRH treatment, diameter of ovulatory v. anovulatory follicles differed (6.44±0.03v. 5.1±0.4 mm; P=0.00). Overall, growth rate of dominant follicles following GnRH was 0.2±0.11mm and did not differ between ovulatory and anovulatory goats (0.29±0.13v. 0.13±0.15 mm; P>0.05). Interval to the emergence of a new wave following GnRH was prolonged for Day 4 compared to Day 2, 6, and 8 (i.e. 22v. 8, 11, and 12 h; respectively, P<0.05). In conclusion, GnRH treatment at Day 4 resulted in maximum ovulations as the first-wave dominant follicle reached a size of 6.1 to 7.0 mm.

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Thibault, C., et M. C. Levasseur. « Ovulation ». Human Reproduction 3, n^o 4 (mai 1988) : 513–23. http://dx.doi.org/10.1093/oxfordjournals.humrep.a136737.

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Bonin, B. F., J. A. Dellaqua Jr et M. A. Alvarenga. « 165 OVARIAN RESPONSE AND EMBRYO RECOVERY RATES OF OLD MARES TREATED WITH A LOW DOSE OF EQUINE PITUITARY EXTRACT ». Reproduction, Fertility and Development 22, n^o 1 (2010) : 241. http://dx.doi.org/10.1071/rdv22n1ab165.

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Mares older than 15 years have low embryo recovery rates, mostly because of disturbances in follicle or oocyte maturation and early embryonic development. A recent publication showed that circulating LH level is lower in older mares (Ginther et al. 2009 Theriogenology 5, 780-788). Equine pituitary extract (EPE) is rich in LH and consequently is able to increase circulating LH levels after injection into mares. The present study aimed to evaluate the effect of low doses of EPE on follicular growth, ovulation rate, and embryo recovery rates in older mares. Embryo donors (n = 20) were Quarter Horses from a commercial embryo center that ranged in age from 15 to 20 years. Donors were used during 3 consecutive cycles. The first and third cycles were used as control cycles, and the EPE treatment was performed on the second cycle. During estrus in each of the 3 cycles, mares were inseminated with cooled or fresh semen from the same stallion and received an injection of deslorelin (1 mg i.m.) upon detection of at least 1 follicle of 35 to 40 mm in diameter. Embryo flushes were performed on Day 8 post-ovulation and were followed by administration of prostaglandin. On the treated cycle, EPE injections (7 mg twice daily i.m.) were started on Day 8 after ovulation until a preovulatory follicle was observed. The percentage of mares with more than one ovulation was compared using Fisher’s test. The mean number of ovulations and embryos, as well as follicular diameter, was compared using Student’s t-test. The percentage of mares with more than one ovulation as well as the number of ovulations per cycle were higher (P < 0.05) in the EPE-treated cycle (65% of mares and 1.8 ovulations, respectively) than in the control cycles before (5% and 1.0) and after treatment (5% and 1.0). Also, the mean number of embryos recovered per cycle was higher (P < 0.05) in EPE-treated cycles (1.0) than in nontreated cycles (0.42). However, the embryo recovery rate per ovulation was similar (P > 0.05) between nontreated (0.4 embryo) and treated cycles (0.6 embryo). Pregnancy rates of the transferred embryos were also similar between embryos recovered on treated (14/20; 70%) and nontreated cycles (9/17; 55%). The daily growth of the dominant follicle was not altered by the EPE treatment. However, embryos recovered during treated cycles were more advanced in development than controls, with more embryos (P < 0.05) classified as morula or early blastocysts when recoverd during nontreated (58%) v. EPE-treated cycles (0%). Based on the results of the present experiment, we can conclude that EPE treatment was able to increase the reproductive efficiency of older embryo donor mares. The improvement in embryo recovery rates on EPE-treated cycles seemed to be more related to the increase in the number of ovulations per cycle than with an improvement in embryo viability.

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Glazier, A. M., et F. C. Molinia. « Development of a porcine follicle-stimulating hormone and porcine luteinizing hormone induced ovulation protocol in the seasonally anoestrus brushtail possum (Trichosurus vulpecula) ». Reproduction, Fertility and Development 14, n^o 8 (2002) : 453. http://dx.doi.org/10.1071/rd02045.

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Monovulatory brushtail possums (Trichosurus vulpecula) were stimulated with exogenous hormones during seasonal anoestrus to overcome ovarian insensitivity and induce ovulation. Seasonal ovarian insensitivity to pregnant mare serum gonadotrophin (PMSG) was overcome by a new porcine follicle-stimulating hormone/porcine luteinizing hormone (pFSH/pLH) protocol. This protocol was refined because the original treatment produced oocytes with abnormal morphology. Possums (n = 12 per group) received eight injections of pFSH of 1.5, 3.0 or 6.0 mg per injection (at 12-h intervals for 4 consecutive days). Ovulation was induced 12 h after the final pFSH injection with a 4-mg injection of pLH. Control animals were treated with the established protocol of a single injection of 15 IU of PMSG, followed 48 h later with an injection of 4 mg of pLH. All females responded to pFSH/pLH treatment, although optimal stimulation occurred in those receiving 8 × 3 mg pFSH, with 13–14�ovulations and recovery of 11–12 oocytes per female (8 × 1.5 mg pFSH: 13 ovulations, 8–9 oocytes; 8�×�6�mg pFSH: 7–8 ovulations, 4–5 oocytes). In contrast, only seven of 12 females responded to PMSG/pLH and, of those responding, only 2–3 ovulations occurred and only 1–2 oocytes per female were recovered. However, around 80% of oocytes recovered after PMSG/pLH treatment had undergone nuclear maturation (metaphase II/1st polar body) compared with around 60% of oocytes from pFSH/pLH-treated animals. In possums killed from 27 to 39 h after pLH treatment, ovulation onset was first observed from 30 h and by 31.5 h, all animals had completed ovulation. Laparoscopic artificial insemination (LAI) was performed on pFSH/pLH-treated animals to determine whether the oocytes produced were capable of fertilization. Uterine LAI performed 27.5–28.5 h after pLH treatment yielded 11/26 fertilized oocytes (up to 4-cell stage), whereas vaginal LAI performed 13–14 h after pLH treatment yielded 21/53 fertilized oocytes. A proportion of oocytes generated from the refined pFSH/pLH protocol are thus properly mature and capable of fertilization. Further refinement of the protocol is now needed to improve the yield of fully matured oocytes.

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Patel, Dhaval K., et Darshit G. Prajapati. « Study the accuracy of salivary ferning test as a predictor of ovulation ». International Journal of Reproduction, Contraception, Obstetrics and Gynecology 7, n^o 7 (27 juin 2018) : 2699. http://dx.doi.org/10.18203/2320-1770.ijrcog20182866.

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Background: Women probably spent much of their adult life avoiding getting pregnant but when they are actively trying for a baby, it may be taking a little longer time than they hoped. So it is important for the women to know when they are ovulating. Recently, a small hand held microscope (KNOWHEN ovulation microscope) has been developed for the purpose of self-observing ferning patterns in saliva during female fertile period. The purpose of our study is to evaluate the accuracy of salivary ferning test by KNOWHEN ovulation microscope to predict the ovulation and to detect sensitivity and specificity of salivary ferning test and to correlate the salivary ferning with cervical mucus and Trans vaginal sonographic findings (TVS).Methods: This was a prospective observational type of study conducted on all healthy married women volunteers age between 21–40 years attending gynec OPD in sola civil hospital, Ahmedabad, with regular menstrual cycle From April 2016 to September 2016.Results: Salivary ferning test by KNOWHEN ovulation microscope is accurate method of detecting ovulation. Its accuracy was 86.5%.Conclusions: Salivary ferning test is a reliable test to detect fertile period of menstrual cycle. Hence can be use for monitoring ovulation instead of ultrasonography where facility of ultrasonography will not available. Detection of salivary ferning by KNOWHEN microscope has same accuracy as laboratory microscope. KNOWHEN microscope can be use by patient herself to detect fertile period.

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Kusumaningrum, D. A., R. S. Sianturi, F. A. Pamungkas et E. Wina. « The effectiveness of prostaglandin nanoparticles in corpus luteum regression ». IOP Conference Series : Earth and Environmental Science 888, n^o 1 (1 novembre 2021) : 012005. http://dx.doi.org/10.1088/1755-1315/888/1/012005.

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Abstract Research examined the formation of prostaglandin nanoparticles and their effect on corpus luteum (CL) regression carried out at IRIAP. The nanoparticles formation was carried out using the ionic gelation method. The nanoparticles have a particle size of 316.80±0.14 nm, polydispersion index of 0,453±0,001, zeta potential of +17,40±0,85 mV with 69,69±8.81% hormone entrapment. The effectiveness of nanoparticle in CL regression was observed (prostaglandin vs prostaglandin nanoparticles) using ultrasound observation, hormone profile and estrus response. Further, the size of the ovulating follicle, the time of ovulation, the size of the CL and the onset of estrus after the administration of the prostaglandins were observed. The observation showed that the intramuscular administration of prostaglandin and prostaglandin nanoparticles did not significantly differ on the onset of estrus, time of ovulation, the ovulating follicle size, size of CL and progesterone concentration. The onset of estrus occurred on 2.50 ± 0.58 and 2.33 ± 0.52 days, the ovulation time after hormone administration was on days 3.50 ± 0.55 and 2.83 ± 0.75 with the ovulation follicle size of 16, 62 ± 0.96 and 17.03 ± 1.13 mm, while the CL measures at H-3 were 13.56 ± 2.28 and 10.45 ± 0.88, the progesterone H-2 concentrations were 0.299 and 0.395, respectively for prostaglandin and prostaglandin nanoparticles. It can be concluded that the formation of nanoparticles did not impair the effectiveness of hormones in CL regression so that it can be used to increase the effectiveness of estrus synchronization

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