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Tierarztliche Praxis. Ausgabe K,... Aug 2023
PubMed: 38336115
DOI: 10.1055/a-2243-2461 -
Theriogenology Feb 2024To date, there have been no studies testing the capacity of GnRH analogs and respective doses to induce a LH peak in sheep. In this sense, the present study aimed to...
To date, there have been no studies testing the capacity of GnRH analogs and respective doses to induce a LH peak in sheep. In this sense, the present study aimed to evaluate the capacity of different synthetic forms and doses of GnRH in inducing LH release in sheep, and the effect of GnRH administration at timed artificial insemination (TAI) on pregnancy per timed-AI. In experiment 1, ewes (n = 40) received an intravaginal device (IVD) of medroxyprogesterone acetate (MPA; 60 mg) for 7 d and prostaglandin F analog on Day 5. On Day 7, the ewes were allocated randomly into one of eight groups (n = 5/group), which received a GnRH analog at a specific dose, as follows: lecirelin (12.5 or 25 μg), gonadorelin (50 or 100 μg), buserelin acetate (4.2 or 8.4 μg), or deslorelin (375 or 750 μg). Blood samples for LH determination were obtained at 0, 2, 4, and 6 h after GnRH and the IVDs were removed after the last blood collection. The maximal LH concentration induced by gonadorelin at doses of 50 μg and 100 μg (12.0 ± 2.4 ng/mL and 28.6 ± 7.1 ng/mL, respectively) was lower (P < 0.05) than serum LH induced by 8.4 μg of buserelin (78.9 ± 12.9 ng/mL), 375 μg and 750 μg of deslorelin (75.6 ± 7.4 ng/mL and 72.1 ± 10.6 ng/mL, respectively) and 12.5 μg and 25 μg of lecirelin (73.3 ± 17.8 ng/mL and 61.6 ± 5.9 ng/mL, respectively). However, the maximal LH concentration induced by 4.2 μg of buserelin (49.4 ± 5.9 ng/mL) was similar (P > 0.05) to the 100 μg of gonadorelin. The total release of LH (area under the curve - AUC) after treatment with 50 μg of gonadorelin (31.7 ± 5.9 ng h/mL) was lower (P < 0.05) than after other agonists. In a second experiment, 330 ewes were treated with IVD containing MPA for 7 d. Simultaneously with IVD removal, 250 μg of cloprostenol and 200 IU of eCG were administered. Then, ewes were assigned randomly to either no further treatment (control); or to receive 4.2 μg of buserelin acetate (GnRH group) at cervical TAI, which was performed with fresh semen 54 h after IVD withdrawal in all the animals. Higher pregnancy per timed-AI was observed for GnRH (50.3 %) compared to control (40.7 %). We conclude that buserelin acetate (8.4 μg), lecirelin (12.5 and 25 μg) and deslorelin (375 and 750 μg) induced a greater stimulatory effect on LH secretion than gonadorelin treatment. Furthermore, buserelin acetate treatment at TAI increased pregnancy per timed-AI in ewes previously treated with MPA and eCG.
Topics: Pregnancy; Female; Sheep; Animals; Buserelin; Estrus Synchronization; Gonadotropin-Releasing Hormone; Medroxyprogesterone Acetate; Insemination, Artificial; Prostaglandins F; Progesterone; Dinoprost
PubMed: 38065020
DOI: 10.1016/j.theriogenology.2023.12.003 -
Effect of GnRH agonist (deslorelin) on reproductive activity in captive female veiled chameleons ().Veterinarni Medicina Jul 2023Eighteen 5 months old veiled chameleon females () were used in the study. Seven females received subcutaneous implants with gonadotropin-releasing hormone agonist...
Eighteen 5 months old veiled chameleon females () were used in the study. Seven females received subcutaneous implants with gonadotropin-releasing hormone agonist (GnRH) deslorelin acetate whereas eleven females were used as control animals without any implants. Females were kept in five terraria, in groups of four females (in 3 terraria) and groups of three females (in 2 terraria), respectively. A minimum of one female with GnRH implants was present in each terrarium. They were kept under standard husbandry conditions. Females of both groups (females with GnRH and controls, respectively) were monitored for three years. No differences between females with GnRH implants and females without GnRH implants were observed with respect to the presence of large ovarian follicles, number of eggs/female, or number of clutches/female. GnRH implants did not prevent spontaneous reproductive activity in any of the 7 females with implants. Ovariectomy was performed in 8 females (4 females with GnRH implants and 4 control females). Ten females (3 females with GnRH implants and 7 control females) had to be euthanised. In 17 of 18 female veiled chameleons of this study histologic examination revealed heterophilic granulomatous oophoritis. The use of GnRH agonist implants did not prove to be an appropriate method for the control of reproductive function in captive female veiled chameleons.
PubMed: 37982053
DOI: 10.17221/31/2023-VETMED -
Journal of the American Association For... Nov 2023Hormonal contraception is an effective, reversible tool for managing birth rates in humans and nonhuman animals alike. However, manipulating reproductive hormones has...
Hormonal contraception is an effective, reversible tool for managing birth rates in humans and nonhuman animals alike. However, manipulating reproductive hormones has behavioral consequences that can impact social and sexual behavior between conspecifics. First, we studied 18 pairs of nonreproductive titi monkeys () to test the efficacy of a novel method of hormonal contraception (deslorelin acetate implants) on reproductive hormone cycling in females and found significant reductions in urinary estrogens and progestagens among treated females compared to untreated controls. We then studied 35 nonreproductive pairs of coppery titi monkeys () to ascertain whether treating females with one of 2 different forms of hormonal contraception (deslorelin acetate implants ( = 17) or medroxyprogesterone acetate injections ( = 9)) would influence the relationship between pair mates compared to the relationship between untreated females and their vasectomized male mates ( = 9). Over a 5-month period, we found no differences in affiliative behaviors between pairs containing untreated females compared to pairs in which the female was treated with either deslorelin acetate or medroxyprogesterone acetate. Similarly, we found no differences in affiliation between pairs in the 2 treatment groups. This study is the first to examine behavioral consequences of hormonal contraception in a pair-bonding species. The results are encouraging for captive, managed breeding colonies of such social animals, especially those used in behavioral research.
Topics: Humans; Male; Female; Animals; Contraceptive Agents; Callicebus; Medroxyprogesterone Acetate; Social Behavior
PubMed: 37973152
DOI: 10.30802/AALAS-JAALAS-23-000017 -
JFMS Open Reports 2023The aim of this clinical case presentation was to describe the effect of a 4.7 mg deslorelin implant placement in a pregnant queen during the second half of gestation,...
CASE SUMMARY
The aim of this clinical case presentation was to describe the effect of a 4.7 mg deslorelin implant placement in a pregnant queen during the second half of gestation, and the consequences of its removal on the pregnancy and parturition. A 5-year-old female cat exhibiting nesting behaviour and weight gain 10 days after placement of a deslorelin implant was presented for examination. Gestation was confirmed on ultrasound, with two well-formed kittens of a gestational age of approximately 7 weeks. The deslorelin implant placed on the umbilicus was removed 1 week later. No change in the pregnancy was observed after removal of the implant. The fetuses showed no signs of distress on ultrasound and radiography examination 4 days after removal of the implant. One week after implant removal, the queen naturally delivered two healthy kittens. The queen showed maternal behaviour with normal milk production.
RELEVANCE AND NOVEL INFORMATION
In the light of the lack of literature on implant injection and removal in the pregnant queen, this case report showcases a successful birth of healthy kittens without any subsequent adverse effect on the queen. Further study is needed to assess the safety of implant removal during pregnancy and potential use as a means to induce fertile oestrus in the queen.
PubMed: 37873522
DOI: 10.1177/20551169231201606 -
Journal of the American Association For... Nov 2023Sterility in male NHP has long been achieved through surgical castration or vasectomy. However, these techniques are irreversible, require a surgical procedure, and have...
Sterility in male NHP has long been achieved through surgical castration or vasectomy. However, these techniques are irreversible, require a surgical procedure, and have potential consequences such as sperm granulomas and long recovery time. Deslorelin is a gonadotropin-releasing hormone agonist that temporarily and reversibly suppresses sex hormone secretion. Our goal in this study was to investigate the effects of deslorelin on testosterone secretion and testicular volume in male rhesus macaques (). Male macaques ( = 4) each received two, 4.7-mg deslorelin implants subcutaneously in the interscapular region. Serum testosterone and testicular volume were then monitored at specific time points until 10 mo after treatment. Testosterone suppression was defined as testosterone levels lower than 0.6 ng/mL for a sustained period of at least 30 d. After implantation, mean testicular volume was significantly reduced by day 121. Testosterone suppression was observed in all subjects. However, the time from implantation to testosterone suppression and duration of suppression varied. Two macaques were hormonally suppressed by day 26 after implantation and remained suppressed for at least 6 mo. The other 2 macaques were hormonally suppressed by 2 mo after implantation; of these two, one remained suppressed for 70 days while the other was suppressed for at least 245 days. We conclude that deslorelin can safely suppress testosterone secretion in male rhesus macaques, but individual variation in onset and duration of action should be considered when establishing reimplantation time points and potential return to reproductive activity.
Topics: Male; Animals; Testis; Gonadotropin-Releasing Hormone; Macaca mulatta; Testosterone; Semen; Drug Implants; Triptorelin Pamoate
PubMed: 37844997
DOI: 10.30802/AALAS-JAALAS-22-000116 -
Tierarztliche Praxis. Ausgabe K,... Aug 2023Slow-release GnRH agonist implants (SRI) are used for reversible medical downregulation of testicular function in male dogs as an alternative to surgery. The 4.7 mg...
OBJECTIVE
Slow-release GnRH agonist implants (SRI) are used for reversible medical downregulation of testicular function in male dogs as an alternative to surgery. The 4.7 mg deslorelin SRI should reduce testosterone after 6-8 weeks and induce castration-like effects for 6 months (mon). However, some individual variation is described in the field in regard to onset and duration of effect. For this reason, we aimed to study the effects of the 4.7 mg deslorelin SRI in a larger cohort.
MATERIAL AND METHODS
In total 50 intact, healthy male dogs (12-48 months, mon; 9-40 kg) were treated with a 4.7 mg deslorelin SRI into the umbilical area (TG, n=45) or served as untreated controls (CG, n=5). CG dogs were surgically castrated after measurement of testicular dimensions and blood sampling for testosterone. In TG, SRIs remained for 5 mon in place and subsequently 3-7 male dogs were surgically castrated at removal (week, W 0) or 1, 2, 3, 4, 5, 6, 7, 8 or 10 weeks later. Examination parameters were testicular dimensions (before treatment, at 4, 8, 12 W, 5 mon, weekly until castration), testosterone (before treatment, at 8 W, 5 mon, castration) and testicular histology (castration).
RESULTS
Whereas examination parameters did not differ between CG and TG before treatment, testicular volume and testosterone was significantly reduced at all time points during treatment. In all but 3 (8 W) and 2 male dogs (5 mon) testosterone was basal during treatment before removal, whereas the parameters were significantly reduced compared to pre-treatment in the respective dogs. After implant removal, testosterone and testicular volumes increased. However, different to earlier studies, the "restart" was more variable with individual basal testosterone until W7, but also physiological testosterone concentrations in W2. Similarly, histological testicular findings at castration were quite variable: besides an arrest on spermatogonia and spermatocytes, elongated spermatids with normal spermatogenesis were found in individual dogs.
CONCLUSION
Our study confirms the efficacy of the deslorelin SRI, but also individual variation especially regarding reversibility of effects on endocrine and germinative testicular function.
CLINICAL RELEVANCE
Deslorelin SRIs offer a suitable alternative to surgical castration with individual variation to be considered when used in clinical practice.
Topics: Humans; Male; Dogs; Animals; Gonadotropin-Releasing Hormone; Drug Implants; Testis; Testosterone
PubMed: 37820614
DOI: 10.1055/a-2142-4194 -
Animals : An Open Access Journal From... Aug 2023Deslorelin implant use in cats is a medical alternative to surgical sterilization, and due to its prolonged efficacy, its use has shown growing interest in the...
Deslorelin implant use in cats is a medical alternative to surgical sterilization, and due to its prolonged efficacy, its use has shown growing interest in the veterinary community. In the case of breeding facilities, its removal is often requested for the early restoration of testicular function. As anti-Müllerian hormones (AMH) in males is dependent of testosterone secretion, its assay may determine the restoration of testicular steroid secretion. An average of 3 weeks has been already described for tomcats' testicular function resumption after implant removal, but information about AMH concentrations in deslorelin-treated tomcats is lacking. Fourteen tomcats were treated for temporary suppression of fertility with a 4.7 mg deslorelin implant, which was surgically removed after 3, 6 or 9 months (n = 6, 4 and 4 tomcats, respectively). A general clinical and reproductive check with a gonadorelin stimulation test for testosterone determination was performed before deslorelin implant administration. After implant removal, tomcats' testicles were ultrasonographically checked for volume determination every 1-2 weeks with observation of the glans penis (presence or absence of spikes) and blood collection to assay both testosterone and AMH concentrations. AMH concentrations increased significantly during the deslorelin treatment from 20.95 ± 4.97 ng/mL to 82.41 ± 14.59 ng/mL ( < 0.05). Following implant removal, AMH concentrations progressively decreased to pre-treatment levels, with a value of 28.42 ± 7.98 ng/mL on the third week post-removal where testosterone secretion was again detected. Even if a big variability of AMH concentrations exists between male individuals, resumption of tomcats' testicular function following a deslorelin treatment can be determined by AMH assay.
PubMed: 37627341
DOI: 10.3390/ani13162552 -
Theriogenology Oct 2023Gonadotropin-releasing hormone (GnRH) agonists offer an alternative to surgical sterilization in prepubertal dogs, preserving ovarian and uterine functions. However, the...
Gonadotropin-releasing hormone (GnRH) agonists offer an alternative to surgical sterilization in prepubertal dogs, preserving ovarian and uterine functions. However, the clinical and hormonal effects of GnRH agonist application during the late-prepubertal stage remain insufficiently understood. This study aimed to investigate the clinical effect (flare-up) and hormonal changes, specifically serum progesterone (P4) and estradiol (E2) levels, in bitches treated with 4.7 mg deslorelin acetate (DA) implants (Suprelorin®, Virbac, F) during the late prepubertal period. Sixteen clinically healthy kangal cross-breed bitches, aged 7-8 months, with a mean body weight of 20.5 ± 0.8 kg, were implanted with DA. Estrus signs were monitored daily, and blood and vaginal cytological samples were collected every other day for four weeks. Cytological changes were analyzed for overall and superficial cell index. Six out of sixteen DA-treated bitches (EST group; n = 6) exhibited clinical proestrus 8.6 ± 0.6 days after implant insertion. The mean serum concentrations of P4 and E2 at the onset of estrus were 1.38 ± 0.32 ng/ml and 37.38 ± 10.07 pg/ml, respectively. Notably, all non-estrus (N-EST group; n = 10) bitches demonstrated an increase in superficial cell index, in addition to expected cytological changes observed in the EST group. On the 18th day post-implantation, the EST group exhibited a significantly higher number of superficial cells compared to the N-EST group (p < 0.001). DA implantation resulted in cytological profile alterations accompanied by a slight increase in estrogen concentrations in all dogs. However, the flare-up response exhibited significant variability, differing from that observed in adult dogs. This study highlights the importance of meticulous timing and breed-specific considerations when utilizing DA for puberty manipulation in late-prepubertal bitches. The observed cytological and hormonal changes in response to DA implants provide valuable insights, but the variability in flare-up responses warrants further investigation.
Topics: Female; Dogs; Animals; Gonadotropin-Releasing Hormone; Progesterone; Sexual Maturation; Drug Implants; Triptorelin Pamoate
PubMed: 37393746
DOI: 10.1016/j.theriogenology.2023.06.036 -
Animal Reproduction Science Jun 2023Estrus synchronization is necessary for intensive donkey farming. Studies on estrus synchronization in jennies are, however, scarce. We aimed to investigate the...
Estrus synchronization is necessary for intensive donkey farming. Studies on estrus synchronization in jennies are, however, scarce. We aimed to investigate the susceptibility of the donkey corpus luteum to cloprostenol and design a successful estrus synchronization protocol. Firstly, the effects of different cloprostenol doses and the timing effect of cloprostenol treatment on estrous cycle was investigated. The time from treatment to luteolysis, the ovulation interval, pre-ovulatory diameter, and ovulation rates were compared between groups. Secondly, to identify the best protocol, eight estrus synchronization protocols from three categories were examined. In the first category, jennies in groups A (n = 55) and B (n = 30) received a progesterone releasing intra-vaginal device (JVID®) and cloprostenol treatment. In the second category (group C to F), jennies were pretreated with deslorelin, and then treated with JVID and cloprostenol, including groups C (n = 50), D (n = 50), E (n = 70), and F (n = 65). In the third category, jennies were treated with deslorelin and cloprostenol, including groups G (n = 40) and H (n = 40). Comparisons were made among groups regarding the degree of synchronization, ovulation, and pregnancy rates. Treatment with 0.4 mg cloprostenol on the third day following ovulation minimized the length of the luteal phase and estrous cycle. Synchronization rate varied from 60.0% to 88.6% among groups and was highest in group E. Pregnancy rates did not differ among the eight protocols. In conclusion, cloprostenol effectively induced luteolysis in jennies and a treatment protocol combining deslorelin, cloprostenol, and JVID is efficient for estrus synchronization in donkeys.
Topics: Pregnancy; Female; Animals; Estrus Synchronization; Luteolysis; Cloprostenol; Equidae; Corpus Luteum; Progesterone
PubMed: 37235952
DOI: 10.1016/j.anireprosci.2023.107263