Levonorgestrel, not etonogestrel, provides contraception in free-ranging koalas

2010 ◽  
Vol 22 (6) ◽  
pp. 913 ◽  
Author(s):  
E. F. Hynes ◽  
K. A. Handasyde ◽  
Geoff Shaw ◽  
Marilyn B. Renfree
Keyword(s):  
Breeding Season ◽  
Follicular Development ◽  
Urogenital Sinus ◽  
Control Group ◽  
Phascolarctos Cinereus ◽  
Plasma Progesterone ◽  
Contraceptive Effect ◽  
Cytological Smear ◽  
Vaginal Cytology ◽  
Free Ranging

Management of high-density koala (Phascolarctos cinereus) populations is essential because of the browsing damage they inflict on their habitat. We have tested two types of gestagen implant, namely levonorgestrel and etonogestrel, as contraceptives for koalas. Free-ranging female koalas were given either a control, levonorgestrel (70 mg) or etonogestrel (34 or 68 mg) implant before the breeding season. Koalas were monitored every 4–12 weeks for births. Plasma progesterone was measured and a cytological smear of the urogenital sinus was taken. Fertility was high in the control group and the two etonogestrel-treated groups, with approximately 90% of females giving birth. In contrast, no levonorgestrel-treated female produced young during the study. Removal of levonorgestrel implants from six females reversed the contraceptive effect in the next breeding season, whereas the eight females in which the levonorgestrel implants were left in remained infertile for six breeding seasons. Vaginal cytology showed evidence of oestrous cycles during the breeding season in all females from all groups and there was no difference seen in the prevalence of cornified epithelial cells in the oestrous smears. This indirectly suggests that levonorgestrel does not prevent follicular development and oestrous cycling. Plasma progesterone in levonorgestrel-treated females remained low all year, but rose in controls concurrent with the onset of the breeding season. This suggests that levonorgestrel prevents pregnancy by blocking ovulation. Etonogestrel had absolutely no contraceptive effect at the two doses delivered and so is not suitable for controlling koala populations. In contrast, levonorgestrel was effective as a long-term, reversible contraceptive in wild koalas.

scholarly journals Effect of deslorelin on the induction of estrus in anestrous bitches

2010 ◽  
Vol 62 (3) ◽  
pp. 615-621 ◽  
Author(s):  
L.L. Lanna ◽  
A.P. Marques Jr. ◽  
R.H. Douglas
Keyword(s):  
Clinical Signs ◽  
Control Group ◽  
Progesterone Concentration ◽  
Plasma Progesterone ◽  
Clinical Evaluations ◽  
Injectable Formulation ◽  
Vaginal Cytology ◽  
Group 2 ◽  
And Control ◽  
Group 1

The efficacy of one or multiple doses of an injectable formulation of deslorelin (a GnRH agonist) was evaluated to induce estrus in anestrous bitches. Thirteen animals composed three groups: group 1 (n=5, single IM injection of 2mg deslorelin), group 2 (n=5, four IM injections of 2mg deslorelin in alternate days), and control group (n=3, four IM saline injections in alternate days). Daily clinical evaluations, sexual behavior, vaginal cytology, plasma progesterone concentration, ovaryhysterectomy and macroscopic evaluation of the uterus and ovaries were done. In group 1, none of the bitches showed signs of estrus, while two developed clinical signs and vaginal cytology of proestrus. In group 2, all animals presented proestrus, four presented estrus, and three ovulated; resulting in a functional corpus luteum and high progesterone concentration until day 25 of diestrus, when ovaryhysterectomy was performed. The duration of the stages of deslorelin induced cycles and the progesterone profile were similar to those described in the literature, and no side effects were observed. In conclusion, injectable formulation of deslorelin in multiple injections was effective to induce fertile estrus in anestrous bitches.

444 FOLLICLE ASPIRATION/ABLATION AS A TECHNIQUE TO AVOID OVULATION AND INDUCE DIESTRUS CONCENTRATIONS OF PROGESTERONE DURING THE ESTROUS CYCLE IN MARES

2010 ◽  
Vol 22 (1) ◽  
pp. 379
Author(s):  
F. S. Ignacio ◽  
D. F. Montechiesi ◽  
D. R. Bergfelt ◽  
J. N. P. Puoli Filho ◽  
L. R. Carvalho ◽  
...  
Keyword(s):  
Estrous Cycle ◽  
Embryo Transfer ◽  
Follicular Development ◽  
Control Group ◽  
Control Groups ◽  
Plasma Progesterone ◽  
Luteal Regression ◽  
Follicle Aspiration ◽  
Mean Differences ◽  
And Control

The present study aimed to demonstrate that ultrasound-guided follicle aspiration/ablation could circumvent ovulation and induce progesterone production in potential recipient mares sufficient to reach diestrus concentrations and potentially support pregnancy following embryo transfer. Ovulation (Day 0) was detected and follicular development was monitored using transrectal ultrasonography in 29 horse mares during the estrous cycle. On Day 5, all mares were given PGF2α (7.5 mg of Dinoprost trometamine, Lutalyse®, Pfizer, Paulinia, Brazil) and randomly assigned to a control and follicle ablation groups. Mares in the control group (n = 5) were not subject to follicle ablation and were allowed to ovulate. Mares in the ablation groups were distributed according to the diameter of the largest follicle to be ablatedusing transvaginal ultrasonography as follows: F25-29 mm (n = 6); F30-34 mm (n = 6); F35-40 mm (n = 6); F ≥ 40 (n = 6). Blood samples were collected at 24-h intervals from the day before ovulation or follicle ablation until detection of the next ovulation. Plasma progesterone concentrations were measured using a commercial RIA kit with intra- and interassay CV of 7.6% and 8.3%, respectively. Concentrations of progesterone ≥2 ng mL-1 were considered representative of diestrus in the ablation groups. Groups were compared using ANOVA and mean differences among groups were located with Tukey’s test. There was an effect of group (P < 0.05) and the percentage of mares and mean (± SEM) days post-ablation or ovulation that progesterone was ≥2 ng mL-1 for each follicle group were as follows: F25-29, 83% and 6.2 ± 1.1ab; F30-34, 66% and 7.3 ± 0.5a; F35-40, 83% and 5.4 ± 0.6ab; F ≥ 40, 100% and 4.0 ± 0.4bc; and control, 100% and 1.6 ± 0.4c. Values with different superscripts are different (P < 0.05). There was no difference (P > 0.05) in maximum concentrations of progesterone among ablation groups. For 7 days after follicle ablation, concentrations of progesterone (≥2 ng mL-1) were not different (P > 0.05) between ablated and control groups. Correspondingly, the time to spontaneous luteal regression (i.e. progesterone <2 ng mL-1) post-ablation or ovulation was not different (P > 0.05) among groups. In conclusion, aspiration/ablation of follicles ≥25 mm following luteal regression during the estrous cycle resulted in the production of progesterone such that concentrations attained diestrus values that could potentially sustain pregnancy following embryo transfer. The authors wish to acknowledge FUNDUNESP for funding the project.

Fertility control in the koala, Phascolarctos cinereus: the impact of slow-release implants containing levonorgestrel or oestradiol on the production of pouch young

2003 ◽  
Vol 30 (3) ◽  
pp. 207 ◽  
Author(s):  
David R. Middleton ◽  
Bryan Walters ◽  
Peter Menkhorst ◽  
Patrick Wright
Keyword(s):  
Large Scale ◽  
Slow Release ◽  
Management Strategies ◽  
Cost Effective ◽  
Fertility Control ◽  
Control Group ◽  
Phascolarctos Cinereus ◽  
Custom Made ◽  
Free Ranging ◽  
The Impact

Two hormone-based fertility-control treatments were trialed on free-ranging female koalas. Either levonorgestrel or oestradiol-17β was administered in a cylindrical, silastic, sub-dermal implant. Levonorgestrel was administered in a commercially produced implant (Norplant 2, Leiras). Two different doses of oestradiol were administered via custom-made implants of different length (1 cm and 0.5 cm). Treatments were randomly applied to 58 females (each koala receiving a single implant) and a control group of 27 female koalas received no implant. Fertility, as determined by the presence of pouch young, was recorded following capture and examination during June 1998, 1999, 2000 and 2001. Fertility was reduced in all treatment groups but remained high (90%) in the untreated group. Fertility was lowest in koalas that received levonorgestrel (0%) and longer oestradiol implants (5%). The results demonstrate that slow-release implants containing either of these two steroid hormones have the ability to significantly lower fertility of wild koalas for at least four breeding seasons following treatment. No adverse side effects were apparent in any of the treated individuals. Compared with the cost of current management strategies for over-abundant koala populations, their deployment on a large scale should be cost-effective.

scholarly journals Semen-induced luteal phase and identification of a LH surge in the koala (Phascolarctos cinereus)

Reproduction ◽  
2004 ◽  
Vol 128 (5) ◽  
pp. 629-634 ◽  
Author(s):  
S D Johnston ◽  
P O'Callaghan ◽  
K Nilsson ◽  
G Tzipori ◽  
J D Curlewis
Keyword(s):  
Artificial Insemination ◽  
Luteal Phase ◽  
Physical Contact ◽  
Urogenital Sinus ◽  
Saline Control ◽  
Control Group ◽  
Optimal Timing ◽  
Phascolarctos Cinereus ◽  
Lh Surge ◽  
Stimulation Of

The koala ovulates in response to mating. The purpose of this study was to document the LH surge induced by copulation and to investigate the potential roles of mechanical stimulation of the urogenital sinus and deposition of semen in induction of the luteal phase. In experiment 1, serial blood samples from four koalas that underwent normal mating showed elevated concentrations of LH approximately 24–32 h post-coitus. There was no corresponding elevation in LH in koalas (n = 4) that were exposed to the presence of a male but received no physical contact. In experiment 2, koalas on day 2 of oestrus were exposed to one of the following treatments (n = 9 per group): artificial insemination with 1 ml 0.9% sterile saline (control group), insemination with 1 ml koala semen, stimulation of the urogenital sinus with a purposebuilt glass rod (designed to mimic the action of the penis during natural mating) and urogenital stimulation with the glass rod followed by insemination of 1 ml koala semen. Confirmation of a luteal phase was based on evidence of a prolonged return to oestrus, parturition and/or elevated progesterone concentrations. Insemination of saline (0/9) and urogenital stimulation (0/9) failed to induce a luteal phase. Insemination of semen without glass rod stimulation resulted in a luteal phase in 4/9 koalas, three of which gave birth. Insemination of semen in combination with urogenital stimulation produced a luteal phase in 7/9 koalas, four of which gave birth. Semen had a significant effect on induction of the koala luteal phase (P < 0.001) but glass rod stimulation had no such effect (P = 0.335). It was concluded that semen must be involved in the induction of a luteal phase in the koala. The results presented in this study will serve to improve optimal timing and induction of ovulation for artificial insemination in the koala.

Deslorelin implants in free-ranging female eastern grey kangaroos (Macropus giganteus): mechanism of action and contraceptive efficacy

2013 ◽  
Vol 40 (5) ◽  
pp. 403 ◽  
Author(s):  
Michelle E. Wilson ◽  
Graeme Coulson ◽  
Geoff Shaw ◽  
Marilyn B. Renfree
Keyword(s):  
Follicular Development ◽  
Fertility Control ◽  
Ovarian Follicles ◽  
Management Technique ◽  
Contraceptive Efficacy ◽  
Effective Population ◽  
Contraceptive Effect ◽  
Reproductive Life ◽  
Lethal Management ◽  
Free Ranging

Context Fertility control offers a non-lethal management technique for iconic yet overabundant wildlife. Slow-release hormonal implants containing deslorelin show promise for managing free-ranging populations, particularly in peri-urban reserves, but most studies have been limited to captivity. Aims We investigated the efficacy and mechanism of deslorelin implants in free-ranging female eastern grey kangaroos (Macropus giganteus) under realistic management conditions. Methods We assigned females to a deslorelin (9.4 mg, n = 53) or placebo (n = 56) group at three peri-urban sites in Victoria, Australia, and monitored reproductive success for 3 years by observing young in the pouch. We tested the plasma LH response of control and treated females to exogenous GnRH, and compared the size of ovarian follicles between the two groups. Key results Deslorelin implants reduced fertility at all three sites. No deslorelin-treated females bred in Year 1 at Anglesea and Serendip versus 42% and 44% of control females respectively. At Plenty Gorge, 60% of deslorelin-treated females bred in Year 1 versus 100% of control females. In Year 2, between 11% and 39% of the treated females bred versus between 82% and 100% of control females at all sites. The contraceptive efficacy reduced by Year 3 when between 43% and 57% of the treated females bred versus between 85% and 100% of controls. A GnRH challenge elicited higher plasma LH concentrations in control than in treated females, and unlike untreated females, treated females lacked ovarian follicles >2 mm. Conclusions Deslorelin implants reduced fertility in free-ranging female eastern grey kangaroos over three successive breeding seasons. Chronic exposure to deslorelin desensitised the pituitary gland to GnRH and suppressed follicular development, but did not inhibit the development of a blastocyst, pregnancy or lactation in at least some females that had conceived before treatment. Implications Effective population management using deslorelin implants will require females to be re-treated on multiple occasions because the contraceptive effect lasts only a portion of their reproductive life. This would be practical only at sites where kangaroos are relatively easy to capture. The timing of treatment is also important in a species that undergoes embryonic diapause, particularly at sites providing high-quality habitat.

Comparative efficacy of levonorgestrel and deslorelin contraceptive implants in free-ranging eastern grey kangaroos (Macropus giganteus)

2016 ◽  
Vol 43 (3) ◽  
pp. 212 ◽  
Author(s):  
Michelle E. Wilson ◽  
Graeme Coulson
Keyword(s):  
Fertility Control ◽  
Control Group ◽  
Natural Fertility ◽  
Cost Of Treatment ◽  
Contraceptive Effect ◽  
Contraceptive Implants ◽  
The Cost ◽  
Free Ranging ◽  
Equivalent Field

Context Fertility control of females with levonorgestrel or deslorelin implants shows promise for managing populations of overabundant eastern grey kangaroos (Macropus giganteus). Although these implants have been tested separately in captive and free-ranging kangaroos, there has been no direct comparison under equivalent field conditions. Aims We investigated the long-term efficacy of levonorgestrel and deslorelin implants, together with the cost of treatment, ease of administration, and the welfare of the animals, in a side-by-side trial under realistic management conditions. Methods We captured 65 adult female kangaroos over 11 days at a golf course in Anglesea, Victoria, Australia. We assigned each female to one of the following three experimental groups: levonorgestrel (210 mg, n = 18), deslorelin (9.4 mg, n = 24) or procedural control (n = 23). We monitored reproductive success for 8 years, by observing young in the pouch in winter and spring. Key results Natural fertility was high; in most years, less than 20% of control females failed to reproduce. For deslorelin-treated females, the odds of failing to reproduce were four times higher than for the control group; for levonorgestrel-treated females, these odds were 74 times higher. Deslorelin was ineffective after 3 years, whereas levonorgestrel was effective for at least 5 years. Conclusions Levonorgestrel was markedly superior in efficacy, as shown by a stronger contraceptive effect persisting for longer. In other respects, the two implants were comparable, being similar in cost and ease of delivery, and equally safe. Implications Only levonorgestrel implants fulfill their promise for non-lethal, long-term control of kangaroo populations. Deslorelin implants cannot be recommended for this purpose.

A note on attainment of puberty of september-born early-maturing ewe lambs in relation to level of nutrition

1991 ◽  
Vol 53 (3) ◽  
pp. 407-409 ◽  
Author(s):  
F. Forcada ◽  
J. A. Abecia ◽  
L. Zarazaga
Keyword(s):  
Sexual Activity ◽  
Breeding Season ◽  
Ovulation Rate ◽  
Corpora Lutea ◽  
Plasma Progesterone ◽  
Ewe Lambs ◽  
Early Maturing ◽  
Age At Puberty

The attainment of puberty in September-born early-maturing ewe lambs was studied at Zaragoza (latitude 41° 40' N). Thirty twin Salz females were allocated to two groups receiving two nutrition levels after 3 months of age: high (500 g/day lucerne hay and 500 g/day concentrate) (H) and low (500 g/ day lucerne hay) (L). Oestrus was detected daily by aproned rams. Corpora lutea were counted after oestrus and plasma progesterone levels monitored each week.In the first breeding season (January to February) the percentage of females showing sexual activity (silent emulation or oestrus and ovulation) was higher in the H compared with the L group (67 and 20%; P < 0/05). Nonpubertal oestrus before the main breeding season was detected in 67% of animals. In the main breeding season and for H and L groups respectively, percentage of females showing silent ovulation before puberty was 67 and 33% and mean age at puberty extended to 319 (s.e. 4-8) and 314 (s.e. 3·7) days. Ovulation rate at puberty was 1·73 (s.e. 0·13) and 1·33 (s.e. 0·15) respectively (P < 0·05).

scholarly journals Ovarian follicular dynamic and plasma progesterone concentration in Alpine goats on the breeding season

2018 ◽  
Vol 70 (6) ◽  
pp. 2017-2022 ◽  
Author(s):  
N.G. Alves ◽  
C.A.A. Torres ◽  
J.D. Guimarães ◽  
E.A. Moraes ◽  
P.B. Costa ◽  
...  
Keyword(s):  
Breeding Season ◽  
Progesterone Concentration ◽  
Plasma Progesterone

CONCENTRATIONS DE LA PROGESTERONE, DES OESTROGENES ET DU CORTISOL DANS LE PLASMA DES VACHES AYANT DONNE NAISSANCE A DES JUMEAUX OU AYANT EU DES RETENTIONS PLACENTAIRES

1979 ◽  
Vol 59 (3) ◽  
pp. 481-490 ◽  
Author(s):  
P. MATTON ◽  
V. ADELAKOUN ◽  
J. J. DUFOUR
Keyword(s):  
Plasma Concentration ◽  
Postpartum Period ◽  
Multiple Births ◽  
Control Group ◽  
Plasma Progesterone ◽  
Retained Placenta ◽  
Different Types ◽  
Foetal Membranes ◽  
Plasma Steroids ◽  
Peripartum Period

Plasma steroids (cortisol, progesterone, estrone and estradiol) were studied during the peripartum period in cows with three different types of parturition: unifoetal normal (VUN), unifoetal with retained placenta (VRP), multifoetal with or without retained placenta (VG). In the control group, cortisol rose gradually from 8 ng/ml on day −7 to 11 ng/ml on the day of parturition and thereafter came back to the level of day −7. In the VRP group, cortisol was slightly lower than in the control on day −7 and it did not vary significantly before or after parturition. In the group of cows with multiple births, where retained placenta was encountered in 3/4 cases, cortisol was much higher than in control animals. Plasma progesterone decreased gradually from 5.5 ng/ml to less than 1 ng/ml on the day of parturition in the control group. In the group VRP and VG, it was significantly higher than in the control on the 2 days before and on the day of parturition. The patterns of estrone and estradiol were similar in the groups VUN and VRP until the first day following parturition, but much higher in the cows giving birth to twins. During the postpartum period, the drop in estrogens was much slower in the VRP and VG groups than in the VUN control group. These results suggest that retention of the placenta is not linked with the plasma concentration of cortisol but rather associated with an increased level of progesterone on the day of parturition and that the slower decrease in estrogen levels after parturition would be the result of the persisting attachment of the foetal membranes.

Episodic ovarian inhibin secretion is not due to LH pulses in anoestrous ewes

1989 ◽  
Vol 123 (2) ◽  
pp. 173-179 ◽  
Author(s):  
B. K. Campbell ◽  
A. S. McNeilly ◽  
D. T. Baird
Keyword(s):  
Breeding Season ◽  
Plasma Levels ◽  
Single Injection ◽  
Venous Blood ◽  
Follicular Development ◽  
Blood Samples ◽  
A Site ◽  
Ovarian Inhibin ◽  
Secretion Rates

ABSTRACT In sheep, secretion of oestradiol by the ovary is stimulated by pulses of LH but the factors controlling ovarian inhibin secretion are not well understood. We have investigated the effect of a single injection of LH on the ovarian secretion of inhibin. Six anoestrous Finn–Merino ewes which had one ovary autotransplanted to a site in the neck had jugular and timed ovarian venous blood samples collected at 10-min intervals for a total of 5 h. The secretion rates of both inhibin (1–3 ng/min) and oestradiol (0·5–8 ng/min) were similar to those observed during the breeding season indicating significant follicular development in these animals. After injection of 2·5 μg NIH-LH-S25 intravenously the concentration of LH in plasma rose from a baseline of 1·8 ±0·1 (s.e.m.) μg/l to a peak of 3·9 ±0·3 μg/l (P<0·01). This LH pulse stimulated a corresponding increase (P<0·01) in oestradiol secretion from a basal level of 0·9±0·2 ng/min to a peak of 4·6±0·6 ng/min that occurred within 30 min of injection. Although inhibin secretion was episodic in nature, increases were not related to either exogenous or endogenous LH pulses. We conclude that, in contrast to oestradiol, the secretion of inhibin by the ovary is not controlled acutely by changes in plasma levels of LH during anoestrus. Journal of Endocrinology (1989) 123, 173–179

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