scholarly journals Effects of a synthetic gonadotrophin-releasing hormone agonist, leuprolide, on rut-associated events in male red deer

2009 ◽  
Vol 49 (12) ◽  
pp. 1120 ◽  
Author(s):  
G. K. Barrell ◽  
S. C. T. Schaafsma ◽  
M. J. Ridgway ◽  
M. Wellby ◽  
L. A. Miller
Keyword(s):  
Cervus Elaphus ◽  
Red Deer ◽  
Body Condition Score ◽  
Plasma Testosterone ◽  
High Dose ◽  
Release Formulation ◽  
Releasing Hormone ◽  
Condition Score ◽  
Gonadotrophin Releasing Hormone ◽  
Farming Industry

This study examined the effectiveness of leuprolide, a gonadotrophin-releasing hormone agonist, in suppressing rut-associated events in farmed male red deer. In mid-January (~6 weeks before the rut period in the southern hemisphere) adult red deer (Cervus elaphus scoticus) stags that had been allocated to three groups (n = 10 per group) received leuprolide, administered subcutaneously in a 90-day release formulation, at zero (control), low (22.5 mg) or high (45 mg) doses. Following treatment with leuprolide there was evidence of suppression of mean plasma luteinising hormone concentration that was significant (P < 0.05) at 9 weeks. Mean plasma testosterone concentration of all three groups rose following treatment, then declined prematurely in the low- and high-dose leuprolide-treated groups, so that it was significantly (P < 0.05) suppressed (0.66 ± 0.29 and 2.0 ± 0.88 ng mL–1, low and high dose respectively) in early April when the peak value (9.0 ± 1.94 ng mL–1) was recorded from control stags. A reduction in mean liveweight occurred in all three groups through February–April and this did not differ among treatments. However, a corresponding reduction in mean body condition score was greater in the control stags (P < 0.05). There was little effect of leuprolide treatment on aggressive behaviours, but it lowered roaring frequency in the latter period of the rut. The results indicate that this gonadotrophin-releasing hormone agonist has potential for application in the deer farming industry to suppress undesirable effects of the rut.

Examining the impacts of red deer hind body condition score and pasture forage mass on calf weaning weight

2017 ◽  
Vol 57 (3) ◽  
pp. 466 ◽  
Author(s):  
D. R. Stevens ◽  
B. R. Thompson ◽  
G. W. Asher ◽  
I. C. Scott
Keyword(s):  
Body Condition ◽  
Cervus Elaphus ◽  
Red Deer ◽  
Body Condition Score ◽  
Restricted Feeding ◽  
Weaning Weight ◽  
Calf Growth ◽  
Total Milk ◽  
Condition Score ◽  
Average Body

The effect of pre-calving hind body condition and the interaction with pasture forage mass during lactation on calf growth and intake to weaning were investigated. Two-hundred and forty red deer hinds (Cervus elaphus scoticus × hippelaphus) of average body condition score (BCS) 3.5 were subjected to either ad libitum or restricted feeding for the 4 weeks before the expected start of calving (31 October) to create hinds of low (2.5) or high (3.5) BCS. The hinds were then grazed continuously on pasture of either low (<1200 kg DM/ha) or high (>2400 kg DM/ha) forage mass during lactation (29 October–25 March). In a 2 × 2 crossover design liveweight, liveweight gain and pasture intake were measured in both hinds and calves. Low hind body condition score (BCS 2.5) at the onset of lactation resulted in low calf weaning weight (46.9 kg) when forage mass was low, but not when forage mass was high (57.3 kg). High BCS (3.5) in hinds resulted in intermediate calf weaning weight when on low forage mass (51.2 kg) and high calf weaning weight when forage mass was high (56.6 kg). Both BCS and forage mass influenced calculated total milk production.

101 Treatment with gonadotrophin-releasing hormone on Day 7 or 21 does not reduce pregnancy loss in dairy heifers receiving invitro-produced embryos

2020 ◽  
Vol 32 (2) ◽  
pp. 176
Author(s):  
B. J. Duran ◽  
R. V. Sala ◽  
P. L. J. Monteiro ◽  
C. Gamarra ◽  
M. Fosado ◽  
...  
Keyword(s):  
Embryo Transfer ◽  
Pregnancy Loss ◽  
Body Condition Score ◽  
Prostaglandin F2α ◽  
P Value ◽  
Releasing Hormone ◽  
Dairy Heifers ◽  
Condition Score ◽  
Pregnancy Status ◽  
Gonadotrophin Releasing Hormone

Previous research has shown that induction of an accessory corpus luteum (CL) by administration of gonadotrophin-releasing hormone (GnRH) on Day 5 increases circulating progesterone and reduces pregnancy loss between Days 33 and 60 in heifers receiving invitro-produced (IVP) embryos. Therefore, the objective of the present study was to determine whether timing of induction of an accessory CL influenced pregnancy loss in IVP recipients. Holstein heifers (n=1,658) were synchronized using a modified 5-day CIDR CO-Synch protocol. Briefly, heifers received an intravaginal progesterone device (CIDR) on Day −8, Day −3: CIDR removed and first prostaglandin F2α (PGF2α) treatment, Day −2: second PGF2α, and Day 0: GnRH (G1, 100µg of gonadorelin acetate). Oestrus expression was evaluated on Day 0 with the use of an oestrus detection device. Transfer of fresh IVP embryos was performed on Day 7±1 after G1. At the time of transfer, heifers were randomly assigned, in a 2×2 factorial design, to receive GnRH (200µg of gonadorelin acetate) or remain as Control (untreated) at two different times: Day 7 (time of embryo transfer (ET)) or Day 21. Thus, the following groups were formed: Control-Control (n=410); Control-GnRH (n=409); GnRH-Control (n=419); and GnRH-GnRH (n=420). All heifers were evaluated by transrectal ultrasonography to determine number, size, and location of CL on Days 5, 14, 21, 28, 32, and 60 and pregnancy status on Days 28, 32, and 60. Data collected from each heifer included embryo stage and quality, oestrus expression, body condition score, number of transfers, and technician. Pregnancies per embryo transfer (P/ET) and pregnancy loss data were analysed by logistic regression (SAS 9.4). Ovulation to Day 7 treatment was greater (P&lt;0.01) in GnRH treated heifers (70.0%; 585 out of 836) than in untreated Controls (2.7%; 22 of 819). Ovulation to Day 21 treatment was determined only in animals pregnant at Day 28 and was greater (P&lt;0.01) in heifers treated with GnRH (37.6%; 153 of 407) than in untreated controls (1.0%; 4 of 390). There was no effect of Day 7 treatment (P&gt;0.68) or Day 21 treatment (P&gt;0.18), nor a Day 7×Day 21 treatment interaction (P&gt;0.48) on P/ET at Day 32 or 60 (Table 1). Treatment with GnRH on Day 7 or 21 did not alter pregnancy loss between Days 32 and 60 (P&gt;0.10). Heifers with an accessory CL present at Day 32 (11.7%; 41 of 350) had similar (P=0.55) pregnancy loss compared with heifers with no accessory CL (14.4%; 54 of 375). The number of CL present on Day 32 did not affect (P=0.23) pregnancy loss; however, heifers with 3 CL (4.9%; 3 of 61) tended (P&lt;0.10) to have reduced pregnancy loss compared with heifers with 1 CL (14.4%; 54 of 375) or 2 CL (13.2%; 38 of 289). In conclusion, treatment with GnRH on Day 7 or 21 induced an accessory CL; however, it did not affect P/ET on Days 32 or 60 and pregnancy loss. Table 1.Pregnancies per embryo transfer (P/ET) and pregnancy loss in embryo recipients based on timing of treatment with gonadotrophin-releasing hormone (GnRH) Treatment P/ET Day 32% (n) P/ET Day 60% (n) Pregnancy loss% (n) Day 7 Day 21 Control Control 42.4 (410) 36.1 (410) 15.0 (174) GnRH 46.0 (409) 40.7 (409) 11.7 (188) GnRH Control 43.7 (419) 36.8 (419) 15.9 (183) P-value GnRH 43.1 (420) 38.8 (420) 10.0 (181) Day 7 treatment 0.68 0.72 0.96 Day 21 treatment 0.51 0.18 0.11 Interaction 0.48 0.66 0.71

scholarly journals Immunisation against gonadotrophin-releasing hormone (GnRH) reduces agonistic behaviours in male rangeland goats

2016 ◽  
Vol 56 (11) ◽  
pp. 1882 ◽  
Author(s):  
Catherine C. Bishop ◽  
Patricia A. Fleming ◽  
Anne L. Barnes ◽  
Teresa Collins ◽  
David W. Miller
Keyword(s):  
Social Stress ◽  
Body Condition Score ◽  
Control Group ◽  
Agonistic Interactions ◽  
Testosterone Concentration ◽  
Releasing Hormone ◽  
Sterile Saline ◽  
Scrotal Circumference ◽  
Condition Score ◽  
Gonadotrophin Releasing Hormone

Rangeland goat bucks were used to evaluate the efficacy of a commercially available anti-gonadotrophin-releasing hormone vaccine, Improvac (Zoetis Australia, West Ryde, NSW, Australia). The hypothesis tested was that immunisation would suppress testosterone secretion by the testis and agonistic behaviour between male goats. We also compared intervals of 2 and 4 weeks between primary and booster immunisations and monitored responses over a 2-month period. The 45 goats were split into three groups (n = 15): one group receiving the vaccination booster on Day 14, one group receiving the vaccination booster on Day 28, and the Control group receiving sterile saline injections. Body mass, body condition score and scrotal circumference were measured fortnightly, and blood was collected at 2-week intervals and analysed for testosterone concentration. Behavioural interaction tests of 2-min duration were also conducted fortnightly. There was a significant decrease in paired testicular circumference (P < 0.05) and testosterone concentration (P < 0.01) in both vaccination groups by the end of the experiment at Day 60, compared with the Control group. Agonistic interactions measured at Day 60 were significantly reduced in both vaccination groups (P < 0.05) compared with the Control group. These results support the efficacy of Improvac in reducing agonistic behaviours in rangeland goat bucks and suggest that the use of the vaccine may assist in reducing social stress and possible injury in groups of confined male goats.

Plasma LH and testosterone responses to gonadotrophin-releasing hormone in adult red deer (Cervus elaphus) stags during the annual antler cycle

1988 ◽  
Vol 117 (1) ◽  
pp. 35-41 ◽  
Author(s):  
P. F. Fennessy ◽  
J. M. Suttie ◽  
S. F. Crosbie ◽  
I. D. Corson ◽  
H. J. Elgar ◽  
...  
Keyword(s):  
Red Deer ◽  
Plasma Concentrations ◽  
Reproductive Hormones ◽  
Sexual Cycle ◽  
Late Winter ◽  
Releasing Hormone ◽  
Antler Growth ◽  
Velvet Antler ◽  
Antler Cycle ◽  
Gonadotrophin Releasing Hormone

ABSTRACT Eight adult red deer stags were given an i.v. injection of synthetic gonadotrophin-releasing hormone (GnRH) on seven occasions at various stages of the antler cycle, namely hard antler in late winter, casting, mid-velvet growth, full velvet growth, antler cleaning and hard antler both during the rut and in mid-winter. The stags were allocated at random on each occasion to one of four doses, i.e. 1, 3, 10 or 95 μg GnRH. Blood samples were taken before GnRH injection and for up to 2 h after injection. Pituitary and testicular responses were recorded in terms of plasma LH and testosterone concentrations. There was an increase in plasma concentration of LH after the GnRH injection in all stags at all stages of the antler cycle. Dose-dependent responses of LH to GnRH in terms of area under the curve were apparent at all stages of the antler cycle. The lowest responses were recorded at casting, during velvet antler growth and at the rut sampling. The pattern of testosterone response reflected the inter-relationship of the antler and sexual cycles with very low testosterone responses occurring at casting and during velvet antler growth. The responses were higher at antler cleaning and then increased to a maximum at the rut before declining to reach their nadir at casting. The results are consistent with a hypothesis that the antler cycle, as a male secondary sexual characteristic, is closely linked to the sexual cycle and its timing is controlled by reproductive hormones. Low plasma concentrations of testosterone, even after LH stimulation, are consistent with the hypothesis that testosterone is unnecessary as an antler growth stimulant during growth. J. Endocr. (1988) 117, 35–41

THE EFFECT OF CYPROTERONE ACETATE ON THE PLASMA GONADOTROPHIN RESPONSE TO GONADOTROPHIN RELEASING HORMONE

1976 ◽  
Vol 81 (3) ◽  
pp. 680-684 ◽  
Author(s):  
Richard A. Donald ◽  
Eric A. Espiner ◽  
R. John Cowles ◽  
Joy E. Fazackerley
Keyword(s):  
Testosterone Level ◽  
Cyproterone Acetate ◽  
Luteinising Hormone ◽  
Follicle Stimulating Hormone ◽  
Plasma Testosterone ◽  
Plasma Testosterone Level ◽  
Releasing Hormone ◽  
Lh Release ◽  
Gonadotrophin Releasing Hormone ◽  
Male Patients

ABSTRACT Cyproterone acetate (100–150 mg daily) was administered to 8 male patients with excessive libido. Within 3 months a significant fall (P < 0.02) in plasma testosterone was demonstrated. The plasma luteinising hormone (LH) and follicle stimulating hormone (FSH) responses to gonadotrophin releasing hormone (LH/FSH-RH) were also significantly impaired (P < 0.05). A direct correlation between the resting plasma testosterone level and the LH response to LH/FSH-RH was demonstrated (r = 0.743). It is concluded that the fall in plasma testosterone levels in patients receiving cyproterone acetate may be attributed to suppression of LH release, rather than an antiandrogen effect on the testis or hypothalamus.

Effect of long-term inhibition of gonadotrophin secretion by the gonadotrophin-releasing hormone agonist, buserelin, on sex steroid secretion and ovarian morphology in polycystic ovary syndrome

1990 ◽  
Vol 125 (2) ◽  
pp. 317-325 ◽  
Author(s):  
A. F. Macleod ◽  
M. J. Wheeler ◽  
P. Gordon ◽  
C. Lowy ◽  
P. H. Sönksen ◽  
...  
Keyword(s):  
Polycystic Ovary Syndrome ◽  
Gnrh Agonist ◽  
Polycystic Ovary ◽  
Normal Subjects ◽  
Sex Hormone Binding Globulin ◽  
Plasma Testosterone ◽  
Ovary Syndrome ◽  
Releasing Hormone ◽  
Gonadotrophin Releasing Hormone

ABSTRACT In order to investigate the effect of long-term suppression of the gonadotrophin axis in polycystic ovary syndrome, eight affected subjects were given s.c. infusions of gonadotrophin-releasing hormone (GnRH) agonist buserelin for 12 weeks. Hormone measurement and ultrasound studies were carried out weekly, from 6 weeks before to 12 weeks after administration of buserelin. An overnight dexamethasone-suppression test was carried out before and after treatment. Maximal suppression of LH to below the lower limit of that in normal subjects occurred after 6 weeks of treatment with buserelin. Plasma testosterone and androstenedione fell to normal levels during the infusion but reached pretreatment levels during the follow-up period. There was no effect of buserelin on plasma dehydroepiandrosterone sulphate or sex hormone-binding globulin. Ovarian size decreased significantly during the infusion with the disappearance of cysts in six subjects. After cessation of buserelin therapy, there was rapid and spontaneous ovulation which occurred within 3 weeks in all subjects. The results suggest that treatment with this GnRH agonist facilitates ovulation in this condition. Journal of Endocrinology (1990) 125, 317–325

Effect of the body condition of ewes on the secretion of LH and FSH and the pituitary response to gonadotrophin-releasing hormone

1989 ◽  
Vol 120 (3) ◽  
pp. 497-502 ◽  
Author(s):  
S. M. Rhind ◽  
S. McMillen ◽  
W. A. C. McKelvey ◽  
F. F. Rodriguez-Herrejon ◽  
A. S. McNeilly
Keyword(s):  
Body Condition ◽  
Luteal Phase ◽  
Body Condition Score ◽  
Pulse Amplitude ◽  
Ovarian Hormones ◽  
Pulse Frequency ◽  
Follicular Phase ◽  
High Body ◽  
Condition Score ◽  
Gonadotrophin Releasing Hormone

ABSTRACT The effects of body fat content (body condition) of ewes on hypothalamic activity and gonadotrophin-releasing hormone (GnRH) secretion and on pituitary sensitivity to GnRH were investigated using Scottish Blackface ewes. Two groups of 12 ewes were fed so that they achieved either a high body condition score (2·98, s.e.m. = 0·046; approximately 27% of empty body weight as fat) or a low body condition score (1·94, s.e.m. = 0·031; approximately 19% of empty body weight as fat) by 4 weeks before the period of study. Thereafter, they were differentially fed so that the difference in mean condition score was maintained. Oestrus was synchronized, and on day 11 of the subsequent cycle half of the ewes of each group were ovariectomized. On day 12, the remaining ewes were injected (i.m.) with 100 μg prostaglandin F2α analogue and ovariectomized 30 h later. Numbers of large ovarian follicles and corpora lutea present at ovariectomy were recorded. Blood samples were collected at 15-min intervals for 12 h on day 10 of the cycle (luteal phase) and at 10-min intervals from 24 to 30 h after prostaglandin injection (follicular phase). At days 2 and 7 after ovariectomy, samples were collected at 15-min intervals for 8 h and ewes were then injected with 10 μg GnRH and samples were collected for a further 3 h. Samples were assayed for LH and FSH. Ewes in high body condition had more more large follicles than ewes in low body condition during the luteal phase (15·3 vs 6·5; P < 0·05) and follicular phase (11·5 vs 7·0; NS) and a slightly higher mean ovulation rate (1·50 vs 1·20; NS). However, during the luteal and follicular phases of the cycle before ovariectomy there was no effect of condition score on mean LH or FSH concentrations or mean LH pulse frequency or pulse amplitude. Two days after ovariectomy, ewes of high body condition had a higher mean LH pulse frequency than ewes of low body condition (P < 0·05) and higher mean FSH concentrations (P < 0·05). Mean LH concentration and pulse amplitude were not affected. LH and FSH profiles were not affected by body condition on day 7. GnRH-induced increases in LH and FSH concentrations on days 2 and 7 were not affected by body condition. At day 7, but not day 2, ewes ovariectomized during the luteal phase of the cycle had a significantly (P < 0·05) greater GnRH-induced LH release compared with ewes ovariectomized during the follicular phase. It is concluded that body condition directly affects hypothalamic activity and GnRH secretion, but not pituitary sensitivity to GnRH, and that effects on reproductive performance are also mediated through changes in ovarian hormones or in hypothalamo-pituitary sensitivity to ovarian hormones. Journal of Endocrinology (1989) 120, 497–502

Variable duration of reproductive suppression in male coyotes (Canis latrans) treated with a high dose of the gonadotrophin-releasing hormone agonist deslorelin

2017 ◽  
Vol 29 (7) ◽  
pp. 1271 ◽  
Author(s):  
Marjorie J. MacGregor ◽  
Cheryl S. Asa ◽  
Donal C. Skinner
Keyword(s):  
Canis Latrans ◽  
Animal Health ◽  
Management Strategies ◽  
High Dose ◽  
Sperm Production ◽  
Releasing Hormone ◽  
Reproductive Axis ◽  
Gonadotrophin Releasing Hormone ◽  
Breeding Seasons

Effective and humane management strategies for coyotes (Canis latrans) remain elusive. We hypothesised that exposure to a high dose of a gonadotrophin-releasing hormone (GnRH) agonist would cause prolonged suppression of the reproductive axis. Two groups of male coyotes were administered 47 mg deslorelin in the form of either five 9.4-mg controlled-release Suprelorin (Peptech Animal Health, Macquarie Park NSW, Australia) implants (n = 3) or 10 4.7-mg implants (n = 5). In the first group, deslorelin suppressed plasma LH, testosterone and testes volume in two of three coyotes for three breeding seasons. In the second group, two of five deslorelin-treated coyotes had no sperm production after 1 year and plasma LH, FSH, testosterone and testes volume were suppressed. Although plasma gonadotropins and testosterone were suppressed in three treated coyotes in group two, testes volume and sperm production were evident. Because the duration of suppression differed among individual coyotes, we further hypothesised that a variation in deslorelin release underlay the variability. To test this, we analysed in vivo plasma profiles of deslorelin concentrations. These profiles suggested that deslorelin concentrations >100 pg mL–1 are required to maintain suppression in male coyotes. For field implementation, the development of an implant capable of releasing deslorelin for the life of the coyote is necessary.

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