Ovarian function and its manipulation in the tammar wallaby, Macropus eugenii

1993 ◽  
Vol 5 (1) ◽  
pp. 27 ◽  
Author(s):  
JC Rodger ◽  
SJ Cousins ◽  
KE Mate ◽  
LA Hinds
Keyword(s):  
Ovarian Function ◽  
Tammar Wallaby ◽  
Ovarian Activity ◽  
Follicle Development ◽  
Lh Surge ◽  
Macropus Eugenii ◽  
Multiple Ovulation ◽  
Gonadotrophin Releasing Hormone ◽  
The Right ◽  
Pregnant Mare Serum Gonadotrophin

This study aimed to develop a superovulation protocol for the monovulatory tammar wallaby (Macropus eugenii), and examined the regulation of ovarian activity which leads to alternate ovulation in this marsupial. The most effective stimulatory treatment was 20 I.U. pregnant mare serum gonadotrophin (PMSG) given intramuscularly (i.m.) 20 days after the activation of an oestrous cycle by the removal of a sucking pouch young (RPY). Bromocriptine treatment was given at the time of RPY if the animal was in early seasonal quiescence. Mating had generally occurred when animals were examined 2 days after PMSG treatment on the morning of Day 22 RPY. Ovulation occurred only if the animal was treated on Day 22 or 23 (i.e. 2 or 3 days after PMSG) with gonadotrophin releasing hormone (GnRH) to induce a luteinizing hormone (LH) surge. Three 30-micrograms injections of GnRH (in 0.2 mL olive oil) were delivered as i.m. injections at 3-h intervals. Radioimmunoassay confirmed that the PMSG dose used did not elevate circulating steroid hormone concentrations beyond those found in normal cycles and that the GnRH protocol led to an LH surge of at least 6 h. Although multiple ovulation was achieved, the number of ovulations was low (2 or 3 per female). A major factor influencing the low ovulation rate was that generally only one ovary responded. Fertilized eggs and cleaving embryos were obtained. However, the fertility of induced ovulations has not yet been examined systematically. Laparoscopic examination through successive natural cycles confirmed that follicle growth and ovulation in the tammar wallaby alternates between the right and left ovary. Inhibition of follicle development in the corpus luteum (CL)-bearing ovary was also seen in females treated with the exogenous gonadotrophin (PMSG/GnRH) superovulation protocol. Follicle development was inhibited during the first half of the cycle in the non-CL-bearing ovary and during the entire cycle in the CL-bearing ovary. This inhibition seemed to occur at the follicular level because exogenous gonadotrophin was unable to initiate a response during periods of inhibition and the response to gonadotrophin differed in the two ovaries. The number of follicles growing in the non-CL-bearing ovary in response to an exogenous gonadotrophin stimulus was inversely related to the weight of the growing CL for the first 19 days after RPY.(ABSTRACT TRUNCATED AT 400 WORDS)

The use of GNRH to control follicular development in cows

1996 ◽  
Vol 1996 ◽  
pp. 95-95
Author(s):  
A.R. Peters ◽  
S.J. Ward ◽  
P.J. Gordon ◽  
G.E. Mann
Keyword(s):  
Dairy Cows ◽  
Present Experiment ◽  
Luteal Phase ◽  
Ovarian Function ◽  
Steroid Hormone ◽  
Follicular Development ◽  
Follicle Development ◽  
Preovulatory Follicle ◽  
Hormone Production ◽  
Gonadotrophin Releasing Hormone

Fertility after prostaglandin (PG) may be compromised by the variability in timing of oestrus and ovulation, which are in turn influenced by the ovarian follicular status at the time of injection. Gonadotrophin-releasing hormone (GnRH) treatment in the luteal phase a few days before PG can reprogramme and thus synchronise preovulatory follicle development (Wolfenson et al., 1994). A second GnRH treatment can then be given after PG, to further improve the synchrony of ovulation (Pursley et al., 1995). The present experiment was carried out to test the effect of this combined GnRH - PG - GnRH regime on ovarian function and steroid hormone production in dairy cows.

scholarly journals Influence of donor age on development of gonadal tissue from pouch young of the tammar wallaby, Macropus eugenii, after cryopreservation and xenografting into mice

Reproduction ◽  
2002 ◽  
pp. 143-153 ◽  
Author(s):  
D Mattiske ◽  
G Shaw ◽  
JM Shaw
Keyword(s):  
Reproductive Tract ◽  
Follicular Development ◽  
Tammar Wallaby ◽  
Corpora Lutea ◽  
Follicle Development ◽  
Primordial Follicles ◽  
Antral Follicles ◽  
Macropus Eugenii ◽  
Reduced Rate ◽  
Timing Of Onset

Ovaries from a marsupial, the tammar wallaby (Macropus eugenii), were grafted into a eutherian recipient at known stages of development to ascertain whether normal development would occur. Xenografted ovaries from pouch young < 20 days old, before the onset of meiosis, retained few germ cells and developed tubule-like structures reminiscent of seminiferous cords. Ovaries from 50-day-old pouch young, which contain primordial follicles, developed into antral follicles and corpora lutea within the eutherian host, and produced hormones that stimulated the reproductive tract of the host. The timing of onset of antrum formation and the progress of follicle development were advanced relative to the timing of events in ovaries in situ. Frozen-thawed ovaries from 50-day-old donors developed into preantral follicles, but at a reduced rate and number. This finding shows that gonads of a marsupial species can develop as xenografts in a eutherian, forming large antral follicles. Accelerated follicular development in xenografts provides a potentially valuable model for studying the factors that control follicle development. Assisted reproduction of endangered marsupials may also be feasible using follicles from pouch young grown as xenografts in a eutherian host.

Hormones of oestrus and ovulation and their manipulation in marsupials

1996 ◽  
Vol 8 (4) ◽  
pp. 661 ◽  
Author(s):  
LA Hinds ◽  
TP Fletcher ◽  
JC Rodger
Keyword(s):  
In Vitro Fertilization ◽  
Tammar Wallaby ◽  
Monodelphis Domestica ◽  
Ovarian Activity ◽  
Vitro Fertilization ◽  
Macropus Eugenii ◽  
Australian Species ◽  
Maturation In Vitro ◽  
American Laboratory

Oestrus and ovulation occur spontaneously in the majority of marsupials, with behavioural oestrus usually occurring 1-2 days before ovulation. The hormone changes that occur at this time have been described in the most detail for the monovular tammar wallaby Macropus eugenii. The respective roles of the Graafian follicle, corpus luteum and the pituitary in the events leading up to oestrus and ovulation in this species are also reviewed. Recently, various protocols have been developed for superovulation of marsupials, including Australian species, such as the brush-tailed possum, fat-tailed dunnart, brush-tailed bettong and tammar wallaby, and the American laboratory opossum, Monodelphis domestica. These protocols provide an opportunity for studying the regulation of ovarian activity and for the collection of larger quantities of material for the study of gamete maturation, in vitro fertilization and embryonic development.

The Structure and Radiographic Anatomy of the Alimentary Tract of the Tammar Wallaby, Macropus Eugenii (Marsupialia) 1. The Stomach.

1980 ◽  
Vol 28 (3) ◽  
pp. 367 ◽  
Author(s):  
KC Richardson
Keyword(s):  
Gastric Emptying ◽  
Contrast Agent ◽  
Distal Part ◽  
Alimentary Tract ◽  
Tammar Wallaby ◽  
Barium Sulphate ◽  
Macropus Eugenii ◽  
Middle Compartment ◽  
The Right

A description is given of the gross and radiographic anatomy of the stomach of Macropus eugenii. The stomach is in the form of a sigmoid tube beginning at a blind sac on the left side and ending at the caudally directed pylorus on the right side. It is haustrated over the whole length of the proximal compartment and most of the middle compartment. The distal part of the middle compartment, and the distal compartment, are not haustrated. The time, but not the pattern, of distribution and mixing with digesta of orally administered barium sulphate is shown to be different in wallabies which had been recently fed and those which had not been fed for 24 h. The contrast agent was carried from the cardia towards the caudal gastric flexure along the ventricular groove. The barium sulphate first dispersed both cranially and caudally from the ends of the groove and was subsequently mixed with digesta. Gastric emptying was difficult to determine radiographically. No radiopaque material was seen in the duodenum, and digesta were therefore assumed to have passed rapidly through into the jejunum.

157 Effect of a slow-release gonadotrophin-releasing hormone analogue on ovarian activity and oestrous behaviour in mares

2020 ◽  
Vol 32 (2) ◽  
pp. 205
Author(s):  
M. Kaps ◽  
C. Gautier ◽  
C. Cardoso Okada ◽  
J. Kuhl ◽  
J. Aurich ◽  
...  
Keyword(s):  
Ovarian Function ◽  
Slow Release ◽  
Treatment Time ◽  
Prostaglandin F2α ◽  
Control Group ◽  
Ovarian Activity ◽  
Gnrh Analogue ◽  
Dependent Manner ◽  
Releasing Hormone ◽  
Gonadotrophin Releasing Hormone

Oestrus behaviour in mares can contribute to problems in their handleability and reduced performance in equestrian sports. Therefore, methods of transient suppression of oestrous cyclicity in mares are of interest. The aim of our study was to determine whether treatment of mares with slow-release implants containing the gonadotrophin-releasing hormone (GnRH) analogue deslorelin downregulates pituitary GnRH receptors and reduces ovarian function and oestrous behaviour. Shetland mares (age=11.0±1.4 years; bodyweight=185.5±7kg) were oestrous synchronised with two injections of the prostaglandin F2α analogue luprostiol (3.725mg) at an interval of 12 days. One day after the second injection (Day 0), mares were randomly assigned to three groups: slow-release implant with 9.4mg of deslorelin (Suprelorin, Virbac; group D1; n=6), implant with 4.7mg of deslorelin (group D2; n=5), and intramuscular injection of 1.25mg of short-acting deslorelin (control, group C; n=5). Collection of blood samples for analysis of progesterone, LH, and anti-Müllerian hormone (AMH) using established and validated enzyme immunoassays (Scarlet et al. 2018 Theriogenology 117, 72-77), testing for oestrus-like behaviour with a Shetland stallion, and ultrasonography of the genital tract were performed at 2-day intervals until Day 10 after treatment and at 5-day intervals from there. On Days 10 and 45 after treatment, LH stimulation tests with the GnRH agonist buserelin (4µg IV) were performed. Data were normally distributed; differences among groups were analysed using analysis of variance and subsequent Tukey test. Values are means±s.e.m. In all mares without a corpus luteum on Day 0 (progesterone &lt;1ngmL−1; one mare in group D1 and two in group C), ovulation was detected within 9 days after deslorelin treatment. These ovulations were classified as deslorelin induced, whereas ovulations after Day 10 were classified as spontaneous ovulations. The mean interval from deslorelin until the first spontaneous ovulation was 62.0±8.6, 44.2±14.1, and 22.2±3.1 days in groups D1, D2, and C (P&lt;0.05), respectively. Subsequent oestrous cycles were regular. Oestrus-like behaviour until day 50 was reduced in groups D1 (2.0±0.9 days) and D2 (2.4±1.3 days) compared with group C (6.4±1.2 days; P&lt;0.05). Concentration of plasma LH and AMH decreased in group D1 (P&lt;0.05) but not in groups D2 and C. The GnRH stimulation test on Day 10 resulted in an increase (P&lt;0.001) in plasma LH concentration in group C but not in groups D1 and D2 (treatment×time P&lt;0.05). On Day 45, LH concentration increased in all mares in response to buserelin (NS among groups). Within 100 days of treatment, LH concentrations but not AMH concentrations in mares of group D1 returned to baseline. In conclusion, deslorelin slow-release implants transiently suppress ovarian function and oestrus behaviour in mares. Spontaneous ovulation is delayed in a dose-dependent manner. A decrease in AMH concentration suggests inhibitory effects of deslorelin on small antral follicles. Long-term effects on follicular dynamics and fertility in larger horses also need to be assessed.

The use of GNRH to control follicular development in cows

1996 ◽  
Vol 1996 ◽  
pp. 95-95
Author(s):  
A.R. Peters ◽  
S.J. Ward ◽  
P.J. Gordon ◽  
G.E. Mann
Keyword(s):  
Dairy Cows ◽  
Present Experiment ◽  
Luteal Phase ◽  
Ovarian Function ◽  
Steroid Hormone ◽  
Follicular Development ◽  
Follicle Development ◽  
Preovulatory Follicle ◽  
Hormone Production ◽  
Gonadotrophin Releasing Hormone

Fertility after prostaglandin (PG) may be compromised by the variability in timing of oestrus and ovulation, which are in turn influenced by the ovarian follicular status at the time of injection. Gonadotrophin-releasing hormone (GnRH) treatment in the luteal phase a few days before PG can reprogramme and thus synchronise preovulatory follicle development (Wolfenson et al., 1994). A second GnRH treatment can then be given after PG, to further improve the synchrony of ovulation (Pursley et al., 1995). The present experiment was carried out to test the effect of this combined GnRH - PG - GnRH regime on ovarian function and steroid hormone production in dairy cows.

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