The reproductive system and embryonic diapause in the female kangaroo, Marcopodus giganteus

1967 ◽  
Vol 15 (3) ◽  
pp. 441 ◽  
Author(s):  
MJ Clark ◽  
WE Poole
Keyword(s):  
Corpus Luteum ◽  
Mitotic Activity ◽  
Reproductive System ◽  
Luteal Phase ◽  
Post Partum ◽  
Ovarian Follicle ◽  
Initial Period ◽  
Secretory Cells ◽  
Ovarian Activity ◽  
Embryonic Diapause

The reproductive system of the female grey kangaroo consists as in other marsupiais, of two ovaries, two uteri, two lateral vaginae, and a median vaginal canal. The changes which occur during the oestrous cycle or pregnancy can be divided into three phases: (1) a proliferative phase characterized by maturation and rupture of an ovarian follicle and its subsequent transformation into a new corpus luteum, and by cell division in the uteri; (2) a luteal phase, when the corpus luteum is fully formed and the luteal cells attain their maximum size, and the uterine gland cells are tall columnar, with basally situated nuclei; and (3) a post-luteal phase when the secretory cells of the corpus luteum and uteri degenerate. Repair begins in the uteri before the end of pregnancy and this is supplemented by post-partum mitotic activity, but post-partum oestrus does not occur. The uterine glands are small, and ovarian activity is inhibited during the initial period of lactation. A small proportion of females with pouch young over 100 days old return to oestrus and mate. Mitotic activity then ceases in the uteri, in the newly formed corpus luteum, and the blastocyst until the pouch young is lost or approaches the end of pouch life, when mitotic activity is resumed in the corpus luteum and blastocyst. The occurrence of embryonic diapause has been confirmed in both wild and captive animals.

A comparative study of the corpus luteum

1995 ◽  
Vol 7 (3) ◽  
pp. 303 ◽  
Author(s):  
RT Gemmell
Keyword(s):  
Corpus Luteum ◽  
Luteal Phase ◽  
Secretory Granules ◽  
Hormonal Control ◽  
Egg Laying ◽  
Oestrous Cycle ◽  
Corpora Lutea ◽  
Embryonic Diapause ◽  
Alternative Reproductive Strategy ◽  
Uterine Development

The corpus luteum (CL) is a transitory organ which has a regulatory role in reproduction. Sharks, amphibians and reptiles have corpora lutea that produce progesterone which influences the rate of embryonic development. The egg-laying monotremes and the two major mammalian groups, eutherian and marsupial, have a CL that secretes progesterone. Most eutherians have allowed for the uterine development of their young by extending the length of the oestrous cycle and the CL or placenta actively secretes progesterone until birth. Gestation in the marsupial does not extend beyond the length of an oestrous cycle and the major part of fetal development takes place in the pouch. Where the extension of the post-luteal phase in the eutherian has allowed for the uterine development of young, the marsupial has extended the pre-luteal phase of the oestrous cycle and has evolved an alternative reproductive strategy, embryonic diapause. The mechanism for the secretion of hormones from the CL has been controversial for many years. Densely-staining secretory granules have been observed in the CL of sharks, marsupials and eutherians. These granules have been reported to contain relaxin, oxytocin or mesotocin, and progesterone. A hypothesis to suit all available data is that all hormones secreted by the CL are transported within such granules. In conclusion, although there are obvious differences in the mode of reproduction in the two main mammalian groups, it is apparent that there is a great deal of similarity in the hormonal control of regression of the CL and parturition.

PERIPHERAL PLASMA PROGESTERONE CONCENTRATION OF COWS DURING PUBERTY, OESTROUS CYCLES, PREGNANCY AND LACTATION, AND THE EFFECTS OF UNDER-NUTRITION OR EXOGENOUS OXYTOCIN ON PROGESTERONE CONCENTRATION

1970 ◽  
Vol 48 (4) ◽  
pp. 599-614 ◽  
Author(s):  
L. E. DONALDSON ◽  
J. M. BASSETT ◽  
G. D. THORBURN
Keyword(s):  
Luteal Phase ◽  
Post Partum ◽  
Late Pregnancy ◽  
Ovarian Activity ◽  
Progesterone Concentration ◽  
Slow Increase ◽  
Normal Cycle ◽  
Plasma Progesterone ◽  
Peripheral Plasma ◽  
Pregnancy And Lactation

SUMMARY Progesterone concentrations in the peripheral plasma of cows were measured by a protein-binding radioassay method. The mean concentration was lowest at oestrus (0·44 ng/ml) and then increased to a maximum of 6·8 ng/ml about day 14 of the 21-day cycle. The concentration decreased rapidly during the last 4 days of the cycle, reaching low levels on the day before oestrus. There were no significant changes in progesterone concentration during oestrus. After ovariectomy the plasma progesterone concentration decreased to a very low level (< 0·4 ng/ml). After hysterectomy, progesterone concentrations remained high for longer than in a normal cycle. At puberty, plasma progesterone concentrations indicated cyclic ovarian activity before the first observed oestrus. Daily treatment of cows with oxytocin (0·4 u./kg body weight) from day 2 reduced the oestrous cycle length to 9 days, but did not significantly alter the slow increase in plasma progesterone concentration during the first 5 days of the cycle. Plasma progesterone concentrations decreased again after day 5 to low values. Plasma progesterone concentration during early pregnancy was similar to the luteal phase value (4–6 ng/ml), declined during mid-pregnancy and then increased to a maximum (7–8 ng/ml) at about 240 days gestation. The concentration declined 2–3 weeks before calving. During lactation progesterone concentrations were very low until the resumption of cyclic ovarian activity. The first post-partum cycle, whether accompanied by observed oestrus or not, was usually preceded by a small increase in plasma progesterone concentration 3–5 days before the start of the cycle. Undernutrition significantly increased plasma progesterone concentrations in mid- and late pregnancy. Undernutrition of non-pregnant cows increased progesterone concentrations during the luteal phase of the first cycle, but reduced it in later cycles.

Duration of embryonic diapause in the brush-tailed bettong, Bettongia penicillata (Potoroidae): effect of age of quiescent corpus luteum

1996 ◽  
Vol 8 (4) ◽  
pp. 807 ◽  
Author(s):  
MJ Smith
Keyword(s):  
Corpus Luteum ◽  
Post Partum ◽  
Embryonic Diapause ◽  
Maximum Duration ◽  
Bettongia Penicillata ◽  
Diapause Embryo ◽  
Effect Of Age

It has been shown that changes to the frequency of sucking by the pouch young do not affect the time of reactivation of the quiescent corpus luteum and diapause embryo in Bettongia penicillata; these observations led to the suggestion that the corpus luteum may have an inherent maximum duration of quiescence. The aim of the present study was to investigate the effect of the age of the corpus luteum on the timing of its reactivation. Ovulation fails to occur post partum in female B. penicillata isolated from males, and the introduction of a male B. penicillata induces oestrus in females suckling a young in the pouch. Oestrus was induced from Day 23 of lactation to Day 76, in different females, and the corpus luteum became quiescent. All parturitions occurred between Day 95 and Day 103 of lactation (average, Day 98.8), at the time expected if the corpus luteum had been formed post partum. Duration of quiescence of the corpus luteum ranged from 60 days to 10 days, compared with 83.9 +/- 0.43 days in females that mated post partum. The results show that the age of the corpus luteum does not affect the timing of its redevelopment and release of the embryo from diapause near the end of the period of the young being suckled within the pouch.

Anoestrus in the red kangaroo Megaleia rufa (Desmarest).

1964 ◽  
Vol 12 (1) ◽  
pp. 9 ◽  
Author(s):  
AE Newsome
Keyword(s):  
Luteal Phase ◽  
Post Partum ◽  
Arid Environment ◽  
Adaptive Significance ◽  
Oestrous Cycle ◽  
Ovarian Activity ◽  
Previous Pregnancy ◽  
Quiescent Period ◽  
Red Kangaroo ◽  
Prolonged Drought

The red kangaroo, M. rufa, normally has a post-partum oestrus and a quiescent period of lactation as do some other macropod marsupials. The term "quiescent period of lactation" has been defined in this paper as the period of reproductive stasis between post-partum oestrus and the resumption of ovarian activity which follows when the female ceases, or almost ceases to suckle the young. This term is introduced to replace the term "lactation anoestrus". It has been shown that some females failed to undergo post-partum oestrus during prolonged drought, each female having entered anoestrus during the previous pregnancy; such pregnancies were not interrupted, but carried to term, and the young sometimes suckled for 3-4 months. In some other females, anoestrus set in during an unfertilized oestrous cycle. It is thought that anoestrus may result from lack of food because anoestrous females are found only during prolonged drought. The histology of the uteri of lactating anoestrous females has been described, and shown to be indistinguishable from that of the uteri of non-lactating anoestrous females, and very different from that in animals in the quiescent period of lactation. The anoestrous condition appeared in the uterus after the cessation of the luteal phase. Pregnancy is therefore independent of the oestrous cycle in Megaleia when the luteal phase has passed. The onset of anoestrus in Megaleia is compared with that in Elephantulus rupestris jamesoni Chubb, Sorex araneus (L.), Oryctolagus cuniculus (L.), Setonix brachyurus (Quoy & Gaimard), and Potorous tridactjhs (Kerr), all of which usually undergo post-partum oestrus. In Oryctolagus and Elephantulus, anoestrus may lead to the death respectively of the young and foetus. It is suggested that the milder consequences of anoestrus in Megaleia may be of adaptive significance to the species in a semi-arid environment, since the embryos and pouch-young of anoestrous females have a chance to survive drought.

scholarly journals Investigating Post-partum Ovarian Cyclicity Following Various Treatments in Dairy Cows

2019 ◽  
Vol 41 (336) ◽  
pp. 22-25
Author(s):  
Akshay Sharma ◽  
Madhumeet Singh ◽  
Pravesh Kumar ◽  
Pradeep Kumar Dogra
Keyword(s):  
Dairy Cows ◽  
Corpus Luteum ◽  
Body Condition Score ◽  
Post Partum ◽  
Control Group ◽  
Ovarian Activity ◽  
Complete Regression ◽  
Dominant Follicle ◽  
Cyclic Activity ◽  
Follicle Diameter

Abstract The present study envisages the effect of PGF2α and antibiotic treatment on ovarian cyclic activity and regression of corpus luteum verum in post-partum dairy cows. Cows were divided into three treatment (PG8, PG25, antibiotic) and a control group. Ovarian activity was studied by examining follicular dynamics upto 42 days post-partum in which diameter of dominant follicle before first ovulation, the number of days to first ovulation and complete regression of corpus luteum verum were evaluated. Body condition score was recorded for all the cows in different groups. Also, ovulation on ovary ipsilateral or contralateral to previous gravid uterine horn was noted. On transrectal ultrasonography at a 3-day interval, dominant follicle diameter prior to ovulation was significantly higher (p<0.01) in PG8 group. The mean time required for complete regression of CL verum was not significantly (p>0.05) lower in PG8 group i.e. 24.33±1.48 days in comparison to PG25, antibiotic and control group (26.67±1.48, 29.00±1.81and 27.60±1.40 days post-partum, respectively). A subsequent ovarian activity was affected as 70.83 and 66.33% Ist and IInd ovulations occurred on the ovary contralateral to corpus luteum verum. In conclusion, contralateral ovary was more active in terms of ovulation whereas presence of corpus luteum verum had no effect on post-partum ovarian cyclic activity.

Studies on Marsupial Reproduction. 2. The oestrous cycle of Setonix Brachyurus.

1955 ◽  
Vol 3 (1) ◽  
pp. 44 ◽  
Author(s):  
GB Sharman
Keyword(s):  
Corpus Luteum ◽  
Blood Vessels ◽  
Mitotic Activity ◽  
Rapid Growth ◽  
Luteal Phase ◽  
Oestrous Cycle ◽  
Degenerative Changes ◽  
Vaginal Smear ◽  
In The Wild ◽  
Uterine Glands

Setonix brachyurus Quoy and Gaimard is polyoestrous, the length of the cycle being about 28 days. In the wild and in the newly domesticated female, oestrous cycles are resumed in late January after an anoestrous period of 3-5 months. During this period oestrus does not occur and ovary and uterus are shrunken and quiescent. Domestication for periods exceeding 1 yr results in a greatly shortened anoestrous period, culminating in a condition in which oestrus is repeated at regular monthly intervals throughout the year. Pro-oestrus is accompanied by rapid growth of one Graafian follicle, mitotic activity in the uterus, and usually by the onset of cornification in the vaginae and appearance of partly cornified cells in the smear. At oestrus the largest follicle reaches a diameter of almost 3.0 mm. Behavioural oestrus lasts about 12 hr. Ovulation follows 12-24 hr after oestrus and is independent of the act of copulation. Invasion of the collapsed follicle by blood vessels and the growth of a corpus luteum takes place after ovulation. Under the influence of the corpus luteum a luteal phase occurs in the uterus and lasts until about 18 days after oestrus. During the period of activity of the corpus luteum the vaginal smear is almost entirely composed of non-cornified cells and leucocytes. Following the cessation of the luteal phase degenerative changes occur in the uterus and the uterine glands are invaded by leucocytes. The changes during the oestrous cycle in Setonix are compared with those occurring in Didelphis and in other marsupials.

VI.—Studies on the Reproductive System in the Guinea-Pig : Observations on the Ovaries, with special reference to the Corpus Luteum

1935 ◽  
Vol 54 ◽  
pp. 56-66 ◽  
Author(s):  
Thomas Nicol
Keyword(s):  
Guinea Pig ◽  
Special Reference ◽  
Corpus Luteum ◽  
Reproductive System ◽  
Guinea Pigs ◽  
Post Partum ◽  
Corpora Lutea ◽  
Tabular Form

The object of the present paper is to put upon record for the guinea-pig data which I have collected regarding (1) the relation between the number of young in a litter and the number of corpora lutea of pregnancy in the ovaries, (2) the distribution of corpora lutea between the two ovaries in two successive ovulations, and (3) the utilisation of the uterine horns in successive pregnancies. The data were obtained in the course of other researches and are arranged in tabular form (Tables I and II). The records from which they have been collected refer to 40 female guinea-pigs killed post partum, of which 16 were pregnant and 24 had not been reimpregnated. The size of the previous litter is known for 38 of these females; both ovaries were serially sectioned at 10 microns in the 40 animals, but in 4 the records of only one ovary were preserved.

Gonadotrophins and ovarian steroids in cattle.

1985 ◽  
Vol 109 (1) ◽  
pp. 44-49 ◽  
Author(s):  
E. Schallenberger ◽  
S. Prokopp
Keyword(s):  
Positive Feedback ◽  
Luteal Phase ◽  
Jugular Vein ◽  
Post Partum ◽  
Initial Period ◽  
Minimum Threshold ◽  
High Magnitude ◽  
Lh Release ◽  
Lh Secretion ◽  
Stimulation Of

Abstract. The re-establishment of the positive feedback action of oestradiol-17β on both gonadotrophins was assessed in 20 dairy cows receiving three challenges once every 20 days from parturition through day 55 post partum (pp). One mg oestradiol-17β-benzoate dissolved in 5 ml oil was given im every 5 days to groups of 5 cows each. Blood was collected from the jugular vein every 3 – 12 h from 2 days before until 2 days after the injection. No effect of oestradiol-17β on the LH release was exerted at parturition or day 5 pp. A stimulation of LH release started to occur in the majority of cows by day 10 pp. Two types of preovulatory like surges could be elicited: low magnitude LH releases lacking any concomitant FSH increase and parallel high magnitude LH and FSH surges. No cow expressed heat when exhibiting a weak LH surge before day 30 pp and only 30% thereafter. All cows showed oestrus when exhibiting parallel high magnitude LH/FSH surges after day 20 pp but only 40% on days 10 and 15 pp. Progesterone concentrations >0.5 ng/ml prevented the positive feedback action of oestradiol on LH and FSH. An initial negative feedback on FSH was exerted throughout the entire post-partum period comprising the luteal phase. We conclude from these results that a certain minimum threshold frequency of endogenous LH secretion is necessary to allow oestradiol-17β to evoke its unimpaired stimulatory feedback action after an initial period of pituitary refractoriness during the early puerperal anoestrus and acyclic period.

A survey of reproductive performance in dairy herds. Characteristics of the patterns of progesterone concentrations in milk

1986 ◽  
Vol 42 (1) ◽  
pp. 1-10 ◽  
Author(s):  
Glenys A. Bloomfield ◽  
S. V. Morant ◽  
M. J. Ducker
Keyword(s):  
Reproductive Performance ◽  
Luteal Phase ◽  
Post Partum ◽  
Cross Reactivity ◽  
Dairy Herds ◽  
Ovarian Activity ◽  
Ovulatory Cycle ◽  
Normal Cycle ◽  
Milk Samples ◽  
Progesterone Secretion

ABSTRACTProgesterone concentrations were measured by radioimmunoassay in fat-free milk samples obtained three times weekly from calving until day 60 of pregnancy from over 700 cows in commercial dairy herds. Profiles of progesterone concentration during the ovulatory cycle and early pregnancy were also examined. In 94% of the animals cycling had commenced by 60 days post partum and a further 3% had shown some ovarian activity. In 34% of cows, the resumption of regular ovulatory activity was preceded by short periods of progesterone secretion which did not meet the criteria for a 'normal cycle’. Peaks of progesterone cross-reactivity (>0·75 ng/1) were detected at the time of ovulation in proportionately 0·06 of all cycles. There was no relationship between the detection of oestrus and the length of the following progesterone cycle or the concentrations during that cycle. However, there was a tendency for the first progesterone cycle post partum to be more variable in length than later cycles (0·56 within the range 18 to 24 days compared with 0·70 of later cycles; P < 0·001). Extension of the length of the luteal phase occurred in 58 second and later cycles (proportionately 0·141) following inseminations which did not result in calving. However, since the comparable figure for 1053 cycles where no insemination was given was 0·048, the overall figure for embryo mortality later than 24 days after insemination was estimated as 9·3%. Concentrations of progesterone in pregnant animals, compared to non-pregnant animals, and the distributions of luteal lengths between 8 and 21 days long following inseminations not resulting in calving could both be explained by early maternal recognition of pregnancy.

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