Studies of the oestrous cycle, oestrus and pregnancy in the koala (Phascolarctos cinereus)

Reproduction ◽  
2000 ◽  
pp. 49-57 ◽  
Author(s):  
SD Johnston ◽  
MR McGowan ◽  
P O'Callaghan ◽  
R Cox ◽  
V Nicolson

As an integral part of the development of an artificial insemination programme in the captive koala, female reproductive physiology and behaviour were studied. The oestrous cycle in non-mated and mated koalas was characterized by means of behavioural oestrus, morphology of external genitalia and changes in the peripheral plasma concentrations of oestradiol and progestogen. The mean (+/- SEM) duration of the non-mated oestrous cycle and duration of oestrus in 12 koalas was 32.9 +/- 1.1 (n = 22) and 10.3 +/- 0.9 (n = 24) days, respectively. Although the commencement of oestrous behaviour was associated with increasing or high concentrations of oestradiol, there were no consistent changes in the morphology or appearance of the clitoris, pericloacal region, pouch or mammary teats that could be used to characterize the non-mated cycle. As progestogen concentrations remained at basal values throughout the interoestrous period, non-mated cycles were considered non-luteal and presumed anovulatory. After mating of the 12 koalas, six females gave birth with a mean (+/- SEM) gestation of 34.8 +/- 0.3 days, whereas the remaining six non-parturient females returned to oestrus 49.5 +/- 1. 0 days later. After mating, oestrous behaviour ceased and the progestogen profile showed a significant increase in both pregnant and non-parturient females, indicating that a luteal phase had been induced by the physical act of mating. Progestogen concentrations throughout the luteal phase of the pregnant females were significantly higher than those of non-parturient females. Parturition was associated with a decreasing concentration of progestogen, which was increased above that of basal concentrations until 7 days post partum.

1973 ◽  
Vol 21 (1) ◽  
pp. 1 ◽  
Author(s):  
CD Shorey ◽  
RL Hughes

The proliferation and secretory activity of the uterine endometrium in the marsupial T. vulpecula is examined at the cellular and subcellular levels throughout the 26-day oestrous cycle. The observations described are correlated with measured concentrations of progesterone in the peripheral blood plasma. Evidence cited indicates that there are no significant functional differences in the uterine endometrial secretory activity during the 17.5-day gestation period in pregnant females, compared with those in a normal oestrous cycle. Progesterone assays carried out on blood plasma taken from 20 staged animals throughout the oestrous cycle, five of which were at known stages of gestation, also supports the view that pregnancy does not significantly alter the physiological pattern of the reproductive cycle in this marsupial.


1989 ◽  
Vol 123 (3) ◽  
pp. 383-391 ◽  
Author(s):  
G. E. Mann ◽  
B. K. Campbell ◽  
A. S. McNeilly ◽  
D. T. Baird

ABSTRACT Passive immunization was used to investigate the importance of inhibin in the negative feedback loop regulating the production of FSH in sheep. An antiserum raised to the 1–26 peptide fragment of the N-terminus of the α-chain of porcine inhibin was first shown to neutralize the suppressive effects of inhibin on the production of FSH by dispersed ovine pituitary cells in vitro. Groups of five mature Scottish Blackface ewes on day 8 of the luteal phase of the oestrous cycle were then injected with either 10 ml plasma from normal ewes (control) or 10 ml ovine inhibin antiserum. On day 10, luteal regression was induced by an i.m. injection of cloprostenol (100 μg), and ovulation rate determined 6 days later by laparoscopy. Peripheral plasma samples were collected throughout the experimental period. Following treatment, there was no change in the peripheral plasma concentration of LH in either group. Following injection of the inhibin antiserum, the concentration of FSH rose significantly (P<0·001) compared with the control group. The concentration of FSH rose from 1·42 ± 0·06 to a maximum of 2·58 ± 0·23 (s.e.m.) μg/l by 5·6 ±0·9 h, this maximum lasting 9·0±1·1 h. By 32·8 ±6·9 h, the concentration of FSH had returned to pretreatment levels, while the titre of free antibody in the plasma of treated ewes was still high. In the treated ewes, there were one single and four double ovulations compared with three single and two double ovulations in the control group, indicating that the inhibin immunization may have resulted in an increase in ovulation rate. We conclude that the marked rise in the plasma concentration of FSH following injection of inhibin antiserum provides strong evidence that inhibin is an important factor in the regulation of FSH production by the pituitary gland at this time. Journal of Endocrinology (1989) 123, 383–391


1982 ◽  
Vol 9 (1) ◽  
pp. 27 ◽  
Author(s):  
RW Rose ◽  
DJ McCatney

'Thylogale billardierii, which is abundant in Tasmania, is a seasonal breeder with most births in the months April, May and June. Parturition is followed by mating, and the zygote so produced remains dormant until either sucking becomes intermittent near the end of pouch life or the young is lost. The mean length of the oestrous cycle was determined at 30.3 days, not significantly longer than the duration of gestation (30.2 days). Removal of pouch young results in the birth of a new young 28.7 days later. Removal of the corpus luteum results in oestrus 11 days later. Pouch life is 202 days, and vacation of the pouch by the young coincides precisely with parturition and post-partum mating. The young mature at about 14-15 months.


2008 ◽  
Vol 20 (3) ◽  
pp. 386 ◽  
Author(s):  
O. J. Ginther ◽  
M. A. Beg ◽  
A. P. Neves ◽  
R. C. Mattos ◽  
B. P. L. Petrucci ◽  
...  

Plasma concentrations of FSH, LH, oestradiol and progesterone were studied daily during 12 interovulatory intervals and 21 periovulatory periods in nine Miniature ponies. The peak of the FSH surge that was temporally associated with emergence of the future ovulatory follicle occurred when the follicle was ~9 mm, compared with a reported diameter of 13 mm in larger breeds. The ovulatory LH surge involved a slow increase between Days 13 and 18 (ovulation = Day 0; 0.6 ± 0.1 ng day–1), a minimal increase or a plateau on Days 18 to 21 (0.04 ± 0.1 ng day–1), and a rapid increase after Day 21 (2.2 ± 0.4 ng day–1; P < 0.0001). The end of the plateau and the beginning of the rapid increase occurred on the day of maximum concentration in the oestradiol preovulatory surge. An unexpected mean increase and decrease in LH occurred (P < 0.04) on Days 5 to 9. Concentrations of oestradiol and progesterone seemed similar to reported results in larger breeds. Results indicated that in Miniature ponies the peak of the FSH surge associated with emergence of the future ovulatory follicle occurred at a smaller diameter of the future ovulatory follicle than in larger breeds, the ovulatory LH surge increased in three phases, and the ovulatory LH surge was followed by an LH increase and decrease during the early luteal phase.


1999 ◽  
Vol 68 (3) ◽  
pp. 527-532 ◽  
Author(s):  
A. O. Darwash ◽  
G. L. Ward ◽  
G. E. Lamming ◽  
J. A. Woolliams

AbstractIn order to investigate the rationale of manipulating post-ovulation progesterone (P4) concentrations, luteal activity was measured in 10 Holstein-Friesian cows treated with a progesterone-releasing device (CIDR, 1·9 g P4) inserted on the morning of day 2 post-oestrus for a period of 7 days and compared with 10 untreated control animals. Milk samples were collected daily during afternoon milking from 7 days pre- to 24 days post-oestrus and P4 concentrations were measured using enzyme-linked immuno-sorbent assay (ELISA). The milk P4 profiles were used to assess the effects of early post-oestrus P4 elevation on five intervals of the luteal phase. In the treated (T) and control (C) animals, the mean interval from oestrus to P4 rise (≥3 μg/l), was 2·38 (s.e. 0·18) and 4·90 (s.e. 0·28) days, respectively, (P < 0·01). The mean interval from oestrus to the attainment of peak P4 concentrations was not significantly different (P > 0·05) between the T (14·75 (s.e. 1-62) days) and С (14·30 (s.e. 0·70) days) animals, with cows in the T group showing a more variable (F7 9 = 4-30, P < 0·05) interval to the occurrence of the peak. The interval from peak P4 to corpus luteum (CL) regression (when P4 fell below ≥3 μg/l) was not significantly different between the T (4·13 (s.e. 1·30 days) and С (5·60 (s.e. 0·88) days) groups. Furthermore, CIDR insertion did not alter luteal phase length, number of days with P4 concentrations ≥3 μg/l (T = 16·50 (s.e. 0·80) v.C = 15·00 (s.e. 0·47) days) or the interval from oestrus to CL regression (T = 18·88 (s.e. 0·79) v.C = 19·90 (s.e. 0·41) days). We conclude that treatment with CIDR 2 days after oestrus successfully increased the availability of P4 to cows without significantly affecting luteal phase characteristics.


1970 ◽  
Vol 48 (4) ◽  
pp. 599-614 ◽  
Author(s):  
L. E. DONALDSON ◽  
J. M. BASSETT ◽  
G. D. THORBURN

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.


1972 ◽  
Vol 53 (3) ◽  
pp. 461-474 ◽  
Author(s):  
F. H. de JONG ◽  
H. J. van der MOLEN

SUMMARY A method for the measurement of dehydroepiandrosterone (DHA) and of its sulphate (DHAS) in human peripheral plasma is described and evaluated. After isolation of DHA from the sample the steroid is oxidized to 4-androstene-3,6,17-trione, which is measured with an electron capture detector after gas—liquid chromatography. It is possible to detect 100 pg 4-androstene-3,6,17-trione. The smallest amount of DHA per sample that can be distinguished from zero is approximately 4 ng, when recovery (27·9 ± 8·8%) and method blank (0·23 ± 0·38 ng) are taken into account. The oxidation to 4-ene-3,6-diones is specific for steroidal 5-en-3-ols. Specificity for DHA is ensured by several chromatographic steps. Repeated estimation of 10 ng DHA gave a mean value of 9·6 ± 1·45 (s.d.) ng (n = 35). Mean concentrations and their standard deviations for DHA and DHAS in peripheral plasma from 18 individuals were 0·50 ± 0·25 and 78 ± 40 μg/100 ml, respectively, at 08.30 h and 0·32 ± 0·17 and 84 ± 34 μg/100 ml, respectively, at 17.00 h of the same day. Levels of plasma cortisol in the same plasma samples estimated with a competitive protein-binding method were 16·7 ± 1·8 and 11·9 ± 3·8 μg/100 ml, respectively. No significant differences between the sexes were observed by any of the three assays. The mean values of the plasma concentrations of cortisol and DHA in the morning were significantly higher than those in the evening (P < 0·001 and P < 0·005, respectively). In contrast, the mean value of the plasma levels of DHAS in the morning was significantly lower than that in the evening (P < 0·025).


1972 ◽  
Vol 52 (4) ◽  
pp. 645-658 ◽  
Author(s):  
H. A. ROBERTSON

The progesterone concentration in peripheral plasma has been measured sequentially in individual cows during the estrous cycle, gestation, at parturition, and post-partum. During the estrous cycle the concentration was lowest just before, during, and just after estrus when the level (0.1–0.4 ng/ml) was similar to that found in three ovariectomized cows. The concentration commenced to rise on the 4th–6th day (day of estrus = 1st day), reached a peak of 3–6 ng/ml on the 11th–13th day, and dropped rapidly over a 24–48-hr period to a basal value 24–72 hr before the next estrus. In early pregnancy, the plasma progesterone concentration was similar to the maximum levels found during the luteal phase of the estrous cycle. Between 90 and 150 days there was an indication of a decline to a relatively low plasma progesterone concentration followed by a variable rise. Prior to parturition, there was a gradual decline over a period of 35–70 days reaching a level of <2.0 ng/ml the day before parturition. Following parturition, the level remained at <0.5 ng/ml until the first sign of the resumption of cyclic activity. The time for this to occur was very variable (20–>60 days). Although not conclusive, the evidence favors the view that for estrous behavior to occur, estrus must be preceded by luteal activity. The discharge of mucus can occur without previous luteal activity.


1979 ◽  
Vol 28 (1) ◽  
pp. 1-12 ◽  
Author(s):  
J. F. Quirke ◽  
J. P. Gosling

ABSTRACTTwenty-four young female sheep, 12 Galways and 12 Fingalways, were used to study the effects of breed and level of nutrition on pre-puberal plasma luteinizing hormone and progesterone concentrations throughout the oestrous cycle and during the first 35 days of pregnancy. The sheep were spring-born and were housed at the end of July when they weighed approx. 34 kg. Equal numbers of animals from each breed were fed on a concentrate diet either ad libitum or at a restricted level that was slightly above their estimated maintenance requirements. The Fingalways reached puberty 1 month earlier than the Galways (11 October ±4 days v. 10 November ±5 days). The restricted animals tended (P < 0·10) to reach puberty later than those fed ad libitum (1 November ±5 days v. 20 October ±4 days). Breed differences in the mean level of plasma progesterone on any day of the oestrous cycle were not significant. The mean daily plasma progesterone concentration was similar for the animals on the two planes of nutrition throughout the cycle, with the exception of day 11 when those fed ad libitum had a significantly higher level (P < 0·01). Plasma progesterone levels in the pregnant females between 5 and 35 days post mating were generally higher in Fingalways than in Galways and were not influenced by plane of nutrition. Plasma luteinizing hormone levels tended to be higher, during the 7 weeks before puberty, in Fingalways than in Galways and in animals fed ad libitum than in those on the restricted level of feeding.


1976 ◽  
Vol 3 (2) ◽  
pp. 93 ◽  
Author(s):  
JC Merchant

Female agile wallabies in captivity reached sexual maturity at about 12 months old and males produced mature spermatozoa by 14 months. Breeding was continuous throughout the year and birth and oestrus were recorded in every month. The mean length of the oestrous cycle was 32.4 days, and the mean gestation period 29.4 days. Females exhibited post-partum oestrus, usually mating within 1 day of birth. Sixty-four young born in captivity comprised 24 males, 30 females and 10 of unknown sex. If a pouch young were removed or lost, the quiescent blastocyst resumed its development, to birth about 26.5 days later. Failure or absence of the blastocyst was followed by an oestrus at about the time of the corresponding post-partum oestrus. Both the oestrous cycle and the interval between removal of a pouch young and oestrus were significantly longer than when a pregnancy intervened. The oestrous cycle was characterized by changes in the proportions of the main cell types in the vaginal smear, and by changes in the appearance of the urogenital opening and the pouch and teats. The approach of oestrus could not be predicted from vaginal smears but the post-oestrous condition was always recognizable even without mating. Young animals first left the pouch for short periods between the ages of 176 and 211 days, and left permanently between 207 and 237 days. Animals of known age were measured and the development of various morphological characters noted at weekly intervals from about birth until 12 months old.


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