Review Control of Reproduction in Macropodid Marsupials

Tyndale-Biscoe, C. H.; Hearn, Jack; Renfree, Marilyn B.

doi:10.1677/joe.0.0630589

Cited by 118 publications

(63 citation statements)

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“…By June, seasonal factors prevent reactivation until around the time of the summer solstice in December when it occurs over a 10-day period (Sharman, 1955;Berger, 1966; Tyndale-Biscoe, Hearn & Renfree, 1974). Diapausing embryos can be reactivated by progesterone injections, but about 10 mg/day is needed for about 10 days, and there is a 50% loss, mostly at early stages of development (Renfree & Tyndale-Biscoe, 1973).…”

Section: Introductionmentioning

confidence: 99%

Concentrations of oestradiol-17 in plasma and corpora lutea throughout pregnancy in the tammar, Macropus eugenii

Shaw¹,

Renfree²

1984

Reproduction

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Summary. Oestradiol-17\g=b\ concentrations were measured by radioimmunoassay in peripheral blood samples from 10 tammar wallabies after their pouch young were removed to terminate embryonic diapause. Oestradiol concentrations rose from 8\m=.\3\m=+-\1\m=.\2 pg/ml on Days 3 and 4 to a peak of 15\m=.\8\m=+-\2\m=.\9 pg/ml on Day 5, coincident with an increase in 'progesterone' concentrations, and then fell to 10\m=.\5 \m=+-\ 2\m=.\7 pg/ml on Day 7. No changes in oestradiol concentrations were associated with parturition. Five females came into oestrus and mated 9\m=.\8 \ m=+-\ 6\m=.\1h post partum; peak concentrations of plasma oestradiol (20\m=.\9\ m=+-\ 2\m=.\1 pg/ml) occurred around the time of mating. None of the females that did not mate up to the end of the experiment at Day 30 had a rise in plasma oestradiol concentrations. Corpora lutea contained 20-100 pg oestradiol during pregnancy. The highest ovarian oestradiol content (> 1200 pg) was measured in whole ovaries containing Graafian follicles from full-term pregnant females. The rise in oestradiol concentrations at Day 5 may be important in the termination of diapause. The post-partum increase in plasma oestradiol concentrations coincides with oestrus.

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Section: Introductionmentioning

confidence: 99%

Concentrations of oestradiol-17 in plasma and corpora lutea throughout pregnancy in the tammar, Macropus eugenii

Shaw¹,

Renfree²

1984

Reproduction

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“…Since the length of gestation is about one day shorter than the oestrous cycle, if females are run with a male and young are removed after birth, a series of up to five pregnancies can occur before seasonal quiescence supervenes. Normally the presence of a suckling young prevents another birth (Tyndale-Biscoe et al 1974). The successive removal of pouch young in this manner allowed us to examine the effects of repeated pregnancy to the same male on parity and on the length of gestation.…”

Section: Introductionmentioning

confidence: 99%

Immunological Aspects of Gestation in the Tammar Wallaby, Macropus eugenii

Walker¹,

Tyndale-Biscoe²

1978

Aust. Jnl. Of Bio. Sci.

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Sensitization to male histocompatibility antigens and repeated pregnancy to the same male were found to have little effect on fertility or length of gestation in the tammar wallaby, M. eugenii. However, in some sensitized females a long interval occurred between removal of pouch young and the next birth. In addition to studies on fertility, the immunological response of female tammars to their mate has been examined by one-way mixed leucocyte culture (MLC) carried out at the beginning and end of one breeding season. In virgin females, examined at the beginning of the breeding season, the MLC response to the prospective mate peaked on day 6. In contrast, by the end of the season, MLC responses were much lower and peaked earlier, on day 3 to day 5.

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“…In our study, this coincided with the greatest volume and coagulation of ejaculates, elevated sperm motility and heaviest male reproductive organs. In the non-breeding season, little or no reproductive activity occurs due to a gradual seasonal inhibition of blastocyst reactivation and postpartum oestrus in adult females until the summer solstice (Tyndale-Biscoe et al 1974). This period coincides with a significant decline in the weight of nearly all reproductive organs and nearly all semen parameters in the tammar and, like the ram and deer, may represent an energy saving when there is little benefit in maintaining optimal breeding condition (Lincoln & Short 1980).…”

Section: Discussionmentioning

confidence: 99%

Changes in semen quality and morphology of the reproductive tract of the male tammar wallaby parallel seasonal breeding activity in the female

Paris¹,

Taggart²,

Shaw³

et al. 2005

Reproduction

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Changes in semen quality and morphology of the male reproductive tract were studied throughout the year in the highly promiscuous tammar wallaby. Body size, semen quality and gross morphology of the reproductive organs were assessed in adult males each month from January to November. The mean weight of males was similar in most periods sampled, but males were slightly heavier in the minor (P < 0.05) than the non-breeding season. Since body weight was correlated with weights of the testes, epididymides and accessory sex glands, organ weights were adjusted for body weight in subsequent analyses. In the major breeding season (late January/early February), when most females go through a brief, highly synchronized oestrus, the testes, prostate, Cowper's glands, crus penis and urethral bulb were heaviest, volume and coagulation of ejaculates were greatest, and sperm motility had increased. Semen samples collected by electroejaculation at this time contained low numbers of spermatozoa, possibly as a result of dilution and entrapment by the seminal coagulum or depletion of epididymal stores during intense multiple mating activity. In the non-breeding season (late May -July), when mating does not normally occur in the wild, there was a significant decrease in the relative weight of nearly all male reproductive organs and a decline in most semen parameters. In the minor breeding season (September -November), when pubertal females undergo their first oestrus and mating, the weights of testes, epididymides and most accessory sex glands had significantly increased similar to those of males in the major breeding season. The total number and motility of ejaculated spermatozoa were highest during this period, but the volume and coagulation of ejaculates and weight of the prostate had only increased to levels that were intermediate between the major and non-breeding seasons. Ejaculate volume was strongly correlated with prostate weight, and % motile spermatozoa was strongly correlated with epididymis weight. Semen quality thus varied seasonally with changes in androgendependent reproductive organs in the male tammar wallaby and appeared to be influenced by the seasonal timing of oestrus in females. Semen quality may also improve in response to an increase in the number of available oestrous females.

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Review Control of Reproduction in Macropodid Marsupials

Cited by 118 publications

References 0 publications

Concentrations of oestradiol-17 in plasma and corpora lutea throughout pregnancy in the tammar, Macropus eugenii

Concentrations of oestradiol-17 in plasma and corpora lutea throughout pregnancy in the tammar, Macropus eugenii

Immunological Aspects of Gestation in the Tammar Wallaby, Macropus eugenii

Changes in semen quality and morphology of the reproductive tract of the male tammar wallaby parallel seasonal breeding activity in the female

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