Induction of the ovulatory LH surge in Asian elephants (Elephas maximus): a novel aid in captive breeding management of an endangered species

2009 ◽  
Vol 21 (5) ◽  
pp. 672 ◽  
Author(s):  
Chatchote Thitaram ◽  
Pornsawan Pongsopawijit ◽  
Saran Chansitthiwet ◽  
Janine L. Brown ◽  
Kannikar Nimtragul ◽  
...  
Keyword(s):  
Captive Breeding ◽  
Unique Feature ◽  
Follicular Phase ◽  
Oestrous Cycle ◽  
Elephas Maximus ◽  
Asian Elephants ◽  
Lh Surge ◽  
Breeding Management ◽  
Gonadotrophin Releasing Hormone ◽  
Natural Mating

A unique feature of the reproductive physiology of Asian elephants (Elephas maximus) is the occurrence of two LH surges before ovulation, instead of one. An anovulatory LH (anLH) surge, the function of which is unknown, occurs consistently 3 weeks before the ovulatory LH (ovLH) surge that induces ovulation. Thus, the ability to induce an ovLH surge would be useful for scheduling natural mating or artificial insemination. The present study tested the efficacy of a gonadotrophin-releasing hormone agonist (GnRH-Ag) to induce LH surges during the follicular phase of the oestrous cycle, which resulted in varied LH responses, but generally none were as high as previously documented natural surges. Thus, for the ovulation-induction trials, nine females were administered 80 μg GnRH-Ag intravenously at three time periods during the oestrous cycle, namely the anovulatory follicular phase, the ovulatory follicular phase and the luteal phase. During the late anovulatory follicular phase, nine of 10 females (90%) responded with an immediate LH surge followed 15–22 days later by an ovLH surge or a post-ovulatory increase in progestagens. In contrast, despite responding to the GnRH-Ag with an immediate increase in LH, none of the females treated during other periods of the oestrous cycle exhibited subsequent ovLH surges. One cow got pregnant from natural mating following the induced ovLH surge. In conclusion, ovLH induction is possible using a GnRH-Ag, but only during a specific time of the anovulatory follicular phase.

Plasma LH concentrations in the ewe in response to repeated injections of low doses of gonadotrophin releasing hormone during the follicular phase of the oestrous cycle

1984 ◽  
Vol 101 (3) ◽  
pp. 365-370 ◽  
Author(s):  
B. J. McLeod ◽  
W. Haresign
Keyword(s):  
Follicular Phase ◽  
Oestrous Cycle ◽  
Low Doses ◽  
Lh Surge ◽  
Releasing Hormone ◽  
Subsequent Cycle ◽  
Small Doses ◽  
Prostaglandin F ◽  
Lh Release ◽  
Gonadotrophin Releasing Hormone

ABSTRACT Oestrus was synchronized in 15 naturally cyclic ewes by the administration of a prostaglandin F2α analogue. Groups of five ewes were then treated i.v. with either small doses of gonadotrophin releasing hormone (GnRH; 125 or 250 ng/injection) or saline, at 2-h intervals from day 14 of the subsequent cycle until 24 h after the onset of oestrus. Treatment with GnRH induced episodic LH release which continued until the onset of a preovulatory LH surge. Mean plasma LH concentrations over this period were significantly (P< 0·001) higher in animals receiving 250 ng GnRH (2·44±0·11 μg/l) than in those receiving either 125 ng GnRH (1·17±0·06 μg/l) or saline (1·14±0·05 μg/l). However, GnRH treatment did not influence the timing of oestrus or mean ovulation rates. J. Endocr. (1984) 101, 365–370

The effect of a potent gonadotrophin-releasing hormone antagonist on ovarian secretion of oestradiol, inhibin and androstenedione and the concentration of LH and FSH during the follicular phase of the sheep oestrous cycle

1990 ◽  
Vol 126 (3) ◽  
pp. 377-384 ◽  
Author(s):  
B. K. Campbell ◽  
A. S. McNeilly ◽  
H. M. Picton ◽  
D. T. Baird
Keyword(s):  
Gnrh Antagonist ◽  
Venous Blood ◽  
Hormone Secretion ◽  
Experimental Period ◽  
Follicular Phase ◽  
Oestrous Cycle ◽  
Blood Samples ◽  
Releasing Hormone ◽  
Inhibitory Feedback ◽  
Gonadotrophin Releasing Hormone

ABSTRACT By selective removal and replacement of LH stimulation we sought to examine the relative importance of inhibin and oestradiol in controlling FSH secretion, and the role of LH in the control of ovarian hormone secretion, during the follicular phase of the oestrous cycle. Eight Finn–Merino ewes which had one ovary removed and the other autotransplanted to a site in the neck were given two injections of a gonadotrophin-releasing hormone (GnRH) antagonist (50 μg/kg s.c.) in the follicular phase of the cycle 27 h and 51 h after luteal regression had been induced by cloprostenol (100 μg i.m.). Four of the ewes received, in addition, i.v. injections of 2·5 μg LH at hourly intervals for 23 h from 42 to 65 h after GnRH antagonist treatment. Ovarian jugular venous blood samples were taken at 10-min intervals for 3 h before and 5 h after the injection of antagonist (24–32 h after cloprostenol) and from 49 to 53 h after antagonist (74–78 h after cloprostenol). Additional blood samples were taken at 4-h intervals between the periods of intensive blood sampling. The GnRH antagonist completely inhibited endogenous pulsatile LH secretion within 1 h of injection. This resulted in a marked decrease in the ovarian secretion of oestradiol and androstenedione (P<0·001), an effect that was reversible by injection of exogenous pulses of LH (P<0·001). The pattern of ovarian inhibin secretion was episodic, but removal or replacement of stimulation by LH had no effect on the pattern or level of inhibin secretion. Peripheral concentrations of FSH rose (P<0·01) within 20 h of administration of the antagonist and these increased levels were maintained in ewes given no exogenous LH. In ewes given LH, however, FSH levels declined within 4 h of the first LH injection and by the end of the experimental period the levels of FSH were similar to those before administration of antagonist (P<0·01). These results confirm that ovarian oestradiol and androstenedione secretion, but not inhibin secretion, is under the acute control of LH. We conclude that oestradiol, and not inhibin, is the major component of the inhibitory feedback loop controlling the pattern of FSH secretion during the follicular phase of the oestrous cycle in ewes. Journal of Endocrinology (1990) 126, 377–384

Evidence that the switch from negative to positive feedback at the level of the pituitary gland is an important timing event for the onset of the preovulatory surge in LH in the ewe

1995 ◽  
Vol 145 (2) ◽  
pp. 271-282 ◽  
Author(s):  
I J Clarke
Keyword(s):  
Pituitary Gland ◽  
Negative Feedback ◽  
Luteal Phase ◽  
Bolus Injection ◽  
Pulse Frequency ◽  
Follicular Phase ◽  
Oestrous Cycle ◽  
Lh Surge ◽  
Small Rise ◽  
Lh Secretion

Abstract Experiments were performed to test the hypothesis that there is a negative feedback 'clamp' of ovarian hormones on the hypothalamus and pituitary gland during the follicular phase of the oestrous cycle that limits the secretion of GnRH and LH. GnRH secretion was monitored by sampling the hypophysial portal blood of ewes during the luteal phase of the oestrous cycle and either 24 h or 48 h after the induction of luteolysis by the injection of cloprostenol, a prostaglandin analogue. There was an increase in GnRH pulse frequency in the transition from the luteal to the follicular phase of the cycle. A reduction in the amplitude of GnRH pulses did not occur until 48 h after cloprostenol, suggestive of negative feedback at the level of the hypothalamus that is more profound in the latter part of the follicular phase. The responsivity of the pituitary gland to GnRH was monitored in ewes during the luteal phase of the oestrous cycle and 24 h or 48 h after cloprostenol. Injections of 250 ng or 1000 ng GnRH were given (i.v.) to ewes that had been anaesthetised to suppress endogenous secretion of GnRH and LH. Using the lower dose, the responses 48 h after cloprostenol were not significantly different from those in the luteal phase. With the higher dose of GnRH, a significant (P<0·05) increase in mean responsivity was seen 48 h after cloprostenol. There was, however, a marked variation in response, with some ewes showing profound increases in LH secretion in response to GnRH and others showing responses that were similar to those obtained during the luteal phase of the cycle. These data are interpreted to mean that the secretion of LH is 'clamped' during the follicular phase of the oestrous cycle and the 'clamp' is only released near the time of the preovulatory LH surge. To test whether or not a rise in GnRH input to the pituitary gland could over-ride the 'clamp' on the pituitary secretion of LH in the late follicular phase of the cycle, sheep were treated 40 h after cloprostenol with either a bolus injection of 500 ng GnRH or four pulses of 125 ng GnRH given at 10-min intervals. These treatments caused small elevations in LH secretion but did not always cause preovulatory LH surges. In some cases, a small rise in LH secretion was induced by GnRH treatments and levels of LH in plasma returned to baseline with the preovulatory LH surge occurring a few hours later. In one clear case, a bolus injection of GnRH induced an LH surge. The overall data from the GnRH-treated groups, however, indicated a significant delay in the onset of the LH surge which may have been due to perturbation of the subcellular mechanisms in the gonadotrophs. These data were interpreted to mean that the secretion of LH from the pituitary gland is inhibited up to very soon before the onset of the LH surge. The inhibitory factor could be oestrogen but could also be some other pituitary feedback hormone such as gonadotrophin surge-attenuating factor. It is concluded that the increase in the secretion of GnRH at the time of the onset of the LH surge is closely linked to an increase in the responsivity of the gonadotrophs to GnRH. The latter is not caused by the increase in the secretion of GnRH. Journal of Endocrinology (1995) 145, 271–282

scholarly journals Illegal capture and internal trade of wild Asian elephants (Elephas maximus) in Sri Lanka

2020 ◽  
Vol 42 ◽  
pp. 51-69
Author(s):  
T. G. Supun Lahiru Prakash ◽  
W. A. A. D. Upul Indrajith ◽  
A. M. C. P. Aththanayaka ◽  
Suranjan Karunarathna ◽  
Madhava Botejue ◽  
...  
Keyword(s):  
Sri Lanka ◽  
Captive Breeding ◽  
Elephas Maximus ◽  
Wildlife Trade ◽  
Court System ◽  
Asian Elephants ◽  
Illicit Trade ◽  
Illegal Wildlife Trade ◽  
Domestic Trade ◽  
Captive Populations

The illegal wildlife trade is considered one of the major threats to global biodiversity. Asian elephants (Elephas maximus) have been highly valued by various cultures for use in religious and spiritual contexts, as a draft animal, and more recently, as a tourist attraction. Thus, the demand for captive elephants is high. Wild Asian elephants are taken from the wild, often illegally, to maintain these captive populations due to the unviability of captive breeding programs. For the first time, we documented the extent to which wild elephants are being illegally captured and traded in Sri Lanka between January 2008 and December 2018. We collected data from case records maintained by the Sri Lanka court system where the suspects of illegal elephant trade were prosecuted in addition to information gathered by archives and interviews with various stakeholders. We documented 55 cases where elephants were illegally traded. This is probably an underestimate due to the mortality rate of elephants during capture operations, and challenges in collecting data on this highly organized illicit trade. Nearly equal numbers of male and female elephants were traded and more than 50% of them were juveniles, aged ≤5 years. Significantly more elephants were found to be seized in 2014–2015 than in the other time periods combined. We found evidence of the illegal capture of wild elephants from wildlife protected areas and state forests. More importantly, we identified evidence of corruption of wildlife officers, involvement of politicians and other high-ranking personnel in the illegal wildlife trade, and lack of active enforcement of wildlife law as major challenges to overcome if the illegal capture and domestic trade of wild elephants in Sri Lanka are to be halted. Based on our study, we make a series of recommendations that should result in implementing policy to reduce the trafficking of Asian elephants in Sri Lanka and improve the conservation management of the species.

Mobilization of LH secretory granules in gonadotrophs in relation to gene expression, synthesis and secretion of LH during the preovulatory phase of the sheep oestrous cycle

1995 ◽  
Vol 147 (2) ◽  
pp. 259-270 ◽  
Author(s):  
R J W Currie ◽  
A S McNeilly
Keyword(s):  
Electron Microscopy ◽  
Luteal Phase ◽  
Secretory Granules ◽  
Follicular Phase ◽  
Oestrous Cycle ◽  
Single Type ◽  
Maximum Diameter ◽  
Northern Analysis ◽  
Mrna Levels ◽  
Lh Surge

Abstract Changes in LH secretory granules in pituitary gonadotrophs throughout the sheep oestrous cycle were determined by immunogold localisation of LH at ultrastructural level by electron microscopy. Oestrous cycles in Welsh Mountain ewes were initially synchronised with progestagen sponges and studies carried out in the subsequent cycle. Animals were allocated at random to six groups each of five animals, one killed on day 12 of the luteal phase and the other groups after prostaglandin (PG)-induced luteal regression at PG plus 18 h (early follicular phase), oestrus (PG plus 33·6±1·0 h), oestrus plus 9 h just before the preovulatory LH surge, 1 h after GnRH agonist-induced LH surge at PG plus 48 h (mid-LH surge) and oestrus plus 24 h, after the preovulatory LH surge. Blood samples collected throughout confirmed the pulsatile secretion of LH before and the timing in relation to the preovulatory LH surge. Pituitaries were dissected and processed for transmission electron microscopy and frozen for later extraction of mRNA. Only a single type of LH cell was present in the sheep pituitary. In the luteal phase, LHimmunopositive secretory granules were distributed throughout the cytoplasm in 80% of cells while in 20% of cells granules were polarised to the region of the cell next to a vascular sinusoid. The percentage of polarised cells increased during the follicular phase to 45% at oestrus, 75% at oestrus plus 9 h just before the LH surge and 90% in mid-LH surge. Cell size increased in parallel with polarisation. Gonadotrophs after the LH surge were almost totally devoid of LH granules but prominent LHβ immunoreactivity was observed in the rough endoplasmic reticulum. Analysis of granule diameters revealed a single class of granules with a maximum diameter of 300 nm. Polarised cells had significantly fewer 130–150 nm granules than non-polarised cells, suggesting preferential exocytosis of LH-containing granules of this size from polarised cells. Northern analysis showed that LHβ mRNA levels decreased from luteal through the follicular phase. These results suggest that the preovulatory LH surge in sheep is not related to a change in synthesis of LH but to a progressive recruitment of gonadotrophs into a releasing state, priming, as indicated by polarisation of secretory granules to the region of the cell next to the vascular system. Journal of Endocrinology (1995) 147, 259–270

Effects of passively immunizing ewes against inhibin and oestradiol during the follicular phase of the oestrous cycle

1990 ◽  
Vol 125 (3) ◽  
pp. 417-424 ◽  
Author(s):  
G. E. Mann ◽  
B. K. Campbell ◽  
A. S. McNeilly ◽  
D. T. Baird
Keyword(s):  
Corpus Luteum ◽  
Passive Immunization ◽  
Follicular Phase ◽  
Oestrous Cycle ◽  
Peptide Fragment ◽  
Lh Surge ◽  
Luteal Regression ◽  
Basal Concentration ◽  
Venous Plasma ◽  
Plasma Control

ABSTRACT Passive immunization was used to investigate the importance of inhibin and oestradiol in the control of FSH production during the follicular phase of the oestrous cycle in the sheep. Four groups of five mature Scottish Blackface ewes were injected with normal sheep plasma (control), antiserum to the 1–26α peptide fragment of porcine inhibin, antiserum to oestradiol-17β, or a combination of the two antisera, 24 h following cloprostenol-induced luteal regression. There was no difference in the concentration of LH in jugular venous plasma between the control and inhibin-immunized groups following the injection of normal sheep plasma or inhibin antiserum, with both groups exhibiting normal LH surges. In both the groups immunized against oestradiol, the basal concentration of LH rose by 25–30% (P<0.05) during the 96-h period following injection, while the LH surge and consequent formation of a corpus luteum was inhibited. In all three immunized groups there was a significant (P<0.001) rise in the concentration of FSH starting 3.8–4.8 h after the injection of antiserum. The duration of the rise was similar in the groups injected with oestradiol antiserum alone (43.6±12.8 h) or in combination with inhibin antiserum (40.6 ± 11.7 h), but was significantly (P<0.05) shorter in the group immunized against inhibin alone (17.0 ± 0.5 h). The rise in FSH was similar in the groups immunized against inhibin (142 ± 6%) or oestradiol (143±4%) alone, and was significantly (P<0.01) greater in the group injected with both antisera (195± 17%). These results provide evidence that both oestradiol and inhibin play a role in regulating the concentration of FSH during the follicular phase of the oestrous cycle, while reinforcing the hypothesis that inhibin is not involved in the regulation of LH production. Journal of Endocrinology (1990) 125, 417–424

Lateralization in trunk and forefoot movements in a population of free-ranging Asian elephants (Elephas maximus).

2015 ◽  
Vol 129 (4) ◽  
pp. 377-387 ◽  
Author(s):  
P. Keerthipriya ◽  
Rachna Tewari ◽  
T. N. C. Vidya
Keyword(s):  
Elephas Maximus ◽  
Asian Elephants ◽  
Free Ranging

Social Dynamics of a Newly Integrated Bachelor Group of Asian Elephants (Elephas maximus): Welfare implications

2021 ◽  
pp. 1-18
Author(s):  
Amy L. Schreier ◽  
Taylor S. Readyhough ◽  
Anneke Moresco ◽  
Maura Davis ◽  
Sharon Joseph
Keyword(s):  
Social Dynamics ◽  
Elephas Maximus ◽  
Asian Elephants ◽  
Welfare Implications

THE OCCURRENCE OF ELEPHANT ENDOTHELIOTROPIC HER-PESVIRUS IN CAPTIVE ASIAN ELEPHANTS (ELEPHAS MAXIMUS): FIRST CASE OF EEHV4 IN ASIA

2013 ◽  
Vol 44 (1) ◽  
pp. 100-104 ◽  
Author(s):  
Supaphen Sripiboon ◽  
Pallop Tankaew ◽  
Grishda Lungka ◽  
Chatchote Thitaram
Keyword(s):  
Elephas Maximus ◽  
Asian Elephants ◽  
First Case

Seasonal and steroid-dependent effects on the modulation of LH secretion in the ewe by intracerebroventricularly administered β-endorphin or naloxone

1989 ◽  
Vol 122 (2) ◽  
pp. 509-517 ◽  
Author(s):  
R. J. E. Horton ◽  
H. Francis ◽  
I. J. Clarke
Keyword(s):  
Breeding Season ◽  
Luteal Phase ◽  
Pulse Frequency ◽  
Opioid Peptide ◽  
Follicular Phase ◽  
Oestrous Cycle ◽  
Opioid Antagonist ◽  
Endogenous Opioid ◽  
Endogenous Opioid Peptide ◽  
Lh Secretion

ABSTRACT The natural opioid ligand, β-endorphin, and the opioid antagonist, naloxone, were administered intracerebroventricularly (i.c.v.) to evaluate effects on LH secretion in ovariectomized ewes and in ovariectomized ewes treated with oestradiol-17β plus progesterone either during the breeding season or the anoestrous season. Ovary-intact ewes were also studied during the follicular phase of the oestrous cycle. Jugular blood samples were taken at 10-min intervals for 8 h and either saline (20–50 μl), 100 μg naloxone or 10 μg β-endorphin were injected i.c.v. after 4 h. In addition, luteal phase ewes were injected i.c.v. with 25 μg β-endorphin(1–27), a purported endogenous opioid antagonist. In ovariectomized ewes, irrespective of season, saline and naloxone did not affect LH secretion, but β-endorphin decreased the plasma LH concentrations, by reducing LH pulse frequency. The effect of β-endorphin was blocked by administering naloxone 30 min beforehand. Treating ovariectomized ewes with oestradiol-17β plus progesterone during the breeding season reduced plasma LH concentrations from 6–8 μg/l to less than 1 μg/l. In these ewes, saline did not alter LH secretion, but naloxone increased LH pulse frequency and the plasma concentrations of LH within 15–20 min. During anoestrus, the combination of oestradiol-17β plus progesterone to ovariectomized ewes reduced the plasma LH concentrations from 3–5 μg/l to undetectable levels, and neither saline nor naloxone affected LH secretion. During the follicular phase of the oestrous cycle, naloxone enhanced LH pulse frequency, which resulted in increased plasma LH concentrations; saline had no effect. In these sheep, β-endorphin decreased LH pulse frequency and the mean concentrations of LH, and this effect was prevented by the previous administration of naloxone. The i.c.v. administration of β-endorphin(1–27) to luteal phase ewes did not affect LH secretion. These data demonstrate the ability of a naturally occurring opioid peptide to inhibit LH secretion in ewes during the breeding and non-breeding seasons, irrespective of the gonadal steroid background. In contrast, whilst the gonadal steroids suppress LH secretion in ovariectomized ewes during both seasons, they only appear to activate endogenous opioid peptide (EOP)-mediated inhibition of LH secretion during the breeding season. Furthermore, these data support the notion that LH secretion in ovariectomized ewes is not normally under the control of EOP, so that naloxone has no effect. Journal of Endocrinology (1989) 122, 509–517

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