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.

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
Keyword(s):  
Luteal Phase ◽  
Post Partum ◽  
Plasma Concentrations ◽  
External Genitalia ◽  
Oestrous Cycle ◽  
Phascolarctos Cinereus ◽  
Pregnant Females ◽  
Peripheral Plasma ◽  
The Mean ◽  
High Concentrations

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.

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.

ARBORIZATION OF CERVICAL MUCUS IN THE EWE

1959 ◽  
Vol 18 (4) ◽  
pp. 350-358 ◽  
Author(s):  
J. I. RAESIDE ◽  
M. F. McDONALD
Keyword(s):  
Seminal Plasma ◽  
Luteal Phase ◽  
Oestrous Cycle ◽  
Cervical Mucus ◽  
Ovarian Activity ◽  
Cellular Debris ◽  
Oestradiol Benzoate ◽  
First Occurrence

SUMMARY The phenomenon of crystallization (arborization) of cervical mucus was studied in the ewe. Some arborization was detected at irregular intervals in a few anoestrous and pregnant ewes, but it did not appear to be related to cyclic ovarian activity. Mucus collected during the normal oestrous cycle showed crystallization patterns from approx. 3 days before oestrus until 2 days after oestrus. Nearly all animals showed the phenomenon on the day before and on the day of oestrus. The prediction of onset of oestrus relative to the first occurrence of arborization was not accurate owing to variability in both the onset and appearance of crystallization patterns. In four cycles ovulation without heat was probably detected by the appearance of arborization in the cervical mucus. Single injections of oestradiol benzoate (ODB) were given during 115 oestrous cycles on the 3–4, 6–7 or 10–12 days after the onset of oestrus in an attempt to determine the quantities of injected oestrogen needed for arborization during the luteal phase. At these periods all, or nearly all, ewes showed arborization when injected with 100, 150 and 100 μg ODB respectively. Further differences between stages of the luteal phase were noted at the lower levels of oestrogen administration. The inhibition of crystallization patterns was noted when blood, seminal plasma and cellular debris were contaminants in cervical mucus. In view of these findings the importance of collecting uncontaminated cervical mucus is stressed. Arborization of cervical mucus appeared to be a better indicator of ovarian activity in the ewe than did arborization in mucus collected from the vagina.

Oestrous and ovarian activities of Finn-cross ewes during the post-partum and the seasonal anoestrous periods

1984 ◽  
Vol 103 (1) ◽  
pp. 155-160 ◽  
Author(s):  
D. Amir ◽  
Miriam Rosenberg ◽  
H. Schindler
Keyword(s):  
Sexual Activity ◽  
Reproductive Performance ◽  
Post Partum ◽  
Oestrous Cycle ◽  
Ovarian Activity ◽  
Plasma Progesterone ◽  
Oestrus Induction ◽  
Autumn And Winter

SummaryThe seasonal and post-partum oestrus occurrence and ovarian activity, assessed by the plasma progesterone concentrations, were studied in Finn-cross ewes following autumn and winter lambings.The last seasonal oestrous cycle was followed by a silent ovulation in C0% of the Finn × Awassi ewes. Silent ovulations during midanoestrus occurred in 50% of the ewes, and in 90% of the animals a silent ovulation preceded the normal resumption of the seasonal sexual activity.The first post-partum oestrus occurred within C0 days after October lambings in about 90% of the ewes. Silent ovulations before the first post-partum oestrus were evident in 70% of the recycling ewes.It is suggested that breeding ewes with ovarian activity after oestrus induction during anoestrous periods might increase the reproductive performance of the flock in a frequent lambing system.

Reproduction in natural populations of the red kangaroo, Megaleia rufa (Desmarest), in central Australia.

1965 ◽  
Vol 13 (5) ◽  
pp. 735 ◽  
Author(s):  
A. E. Newsome
Keyword(s):  
Drought Index ◽  
Natural Populations ◽  
Late Pregnancy ◽  
Arid Environment ◽  
Adaptive Significance ◽  
Severe Drought ◽  
Summer Drought ◽  
Red Kangaroo ◽  
Males And Females ◽  
Central Australia

Reproduction in the red kangaroo, Megaleia rufa (Desmarest), in the arid environment of central Australia is highly opportunistic, and depends on the weather through its control of the food supply for its success. This conclusion is based on the study of 460 males and 1610 females between the years 1958 and 1962. Males and females matured sexually at an average age of about 2.5 and 3 yr, respectively. Drought significantly retarded sexual maturity in females by 6.24� 1.26 months. All females bred when green herbage was abundant after good rains. However, when food was scarce during drought, many females entered anoestrus, the proportion doing so being a probit function of the severity of the drought (measured in units of "drought index" explained in the text). Half of them became anoestrous after 3-5 months of drought in summer. Drought on the more scantily grassed of the two areas studied (they were 15-20 miles apart) was 1.57 times more effective in inducing anoestrus than on the other. All pouch-young survived if good conditions held for about 8 months, but many died during drought, the proportion doing so being a probit function of the increase in severity of drought after they were born. Half of them perished after 1.5-2.5 months of drought in summer. Only 28.7% of all joeys born survived life in the pouch because of the prolonged dry weather. Pouch-young were significantly lighter, and joeys-at-heel were 13.5 � 1.9 days older during drought than at other times. The birth of twin joeys was associated with an abundance of food. During severe drought, many females showed signs of having produced in quick succession one or more joeys which did not live long. Many of these females were anoestrous and suckling a small joey. Since most if not all females which became anoestrous did so during late pregnancy without aborting and subsequently suckled their pouch-young, it is suggested that the adaptive significance of delayed implantation is to ensure that females which have lost a joey and which are about to become anoestrous produce one more joey each. These joeys will be born well into any drought and therefore will have to live for a shorter time than older joeys to survive the drought. The advantage to the species can be gauged from the fact that 50 out of 145 females with young surviving the drought were anoestrous. The ages of their joeys averaged 60.1 � 7.6 days.

scholarly journals Ovarian activity in Fleckvieh, Brown Swiss and two strains of Holstein-Friesian cows in pasture-based, seasonal calving dairy systems

2011 ◽  
Vol 78 (4) ◽  
pp. 464-470 ◽  
Author(s):  
Valérie Piccand ◽  
Susanne Meier ◽  
Erwan Cutullic ◽  
Sara Weilenmann ◽  
Peter Thomet ◽  
...  
Keyword(s):  
Dairy Cows ◽  
Body Condition Score ◽  
Post Partum ◽  
Oestrous Cycle ◽  
The Other ◽  
Breeding Period ◽  
Ovarian Activity ◽  
Brown Swiss ◽  
Holstein Friesian ◽  
Condition Score

The objectives of the study were to compare the ovarian activity of Holstein-Friesian (CH HF), Fleckvieh (CH FV) and Brown Swiss (CH BS) dairy cows of Swiss origin with that of Holstein-Friesian (NZ HF) dairy cows of New Zealand origin, the latter being used as a reference for reproductive performance in pasture-based seasonal calving systems. Fifty, second-lactation NZ HF cows were each paired with a second-lactation Swiss cow (17, 15 and 18 CH HF, CH FV and CH BS respectively) in 13 pasture-based, seasonal-calving commercial dairy farms in Switzerland. Ovarian activity was monitored by progesterone profiling from calving to first breeding service. CH BS cows produced less energy-corrected milk (mean 22·8 kg/d) than the other breeds (26·0–26·5 kg/d) during the first 100 d of lactation. CH HF cows had the lowest body condition score (BCS) at calving and the greatest BCS loss from calving to 30 d post partum. Commencement of luteal activity (CLA) was later for NZ HF than for CH FV (51·5 v. 29·2 d; P <0·01), with CH HF and CH BS intermediate (43 d). On average, NZ HF and CH HF cows had one oestrous cycle before the onset of the seasonal breeding period; this was less (P<0·01) than either CH FV (1·7) or CH BS (1·6). There was a low prevalence of luteal persistency (3%) among the studied cows. First and second oestrous cycle inter-ovulatory intervals did not differ between breeds (20·5–22·6 d). The luteal phase length of CH BS during the second cycle was shorter (10·6 d) than that of the other breeds (13·8–16·0 d), but the inter-luteal interval was longer (9·8 d v. 7·0–8·0 d). The results suggest that the Swiss breeds investigated have a shorter interval from calving to CLA than NZ HF cows.

CONCENTRATION OF PROGESTIN IN THE SERUM OF THE NON-PREGNANT, PREGNANT AND POST-PARTUM EWE

1954 ◽  
Vol 11 (4) ◽  
pp. 323-330 ◽  
Author(s):  
G. M. NEHER ◽  
M. X. ZARROW
Keyword(s):  
Reproductive Cycle ◽  
Luteal Phase ◽  
Post Partum ◽  
Oestrous Cycle ◽  
Pregnant Sheep

SUMMARY The Hooker-Forbes assay was employed to determine the concentration of free progestin in the serum of ewes during various stages of the reproductive cycle. During the oestrous cycle, the concentration varied from 0\m=.\3 to 2μg/ml. at oestrus to 6μg in the luteal phase. During pregnancy, the level of progestin rose from 1 to 2 μg/ml. at mating to a peak of 8–12 μg/ml. at parturition. The concentration of progestin showed a plateau at a level of 6–8 μg from the 40th to the 100th day of pregnancy. A second rise occurred at about the 120th day of pregnancy. In all sheep parturition took place prior to the drop in serum progestin. By the 10th day post-partum, however, the concentration of the hormone declined to 1 or 2 μg/ml. and remained at this level throughout lactation. Removal of the ovaries between the 66th and 114th day of gestation had no effect on the level of progestin in the blood of five ewes. The pregnancies remained unaffected, and the concentration of progestin increased in a manner comparable to that seen in pregnant sheep with intact ovaries. It is suggested that the placenta is the major source of progestin during the last two trimesters of pregnancy in the sheep.

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.

Naloxone evokes a nutritionally dependent LH response in post partum beef cows but not in mid-luteal phase maiden heifers

1995 ◽  
Vol 61 (2) ◽  
pp. 219-230 ◽  
Author(s):  
K. D. Sinclair ◽  
P. J. Broadbent ◽  
J. S. M. Hutchinson
Keyword(s):  
Energy Intake ◽  
Body Condition ◽  
Luteal Phase ◽  
Dry Matter ◽  
Post Partum ◽  
Beef Cows ◽  
High Energy ◽  
Oestrous Cycle ◽  
Blood Samples ◽  
Post Partum Period

AbstractData from two experiments are reported which test the hypothesis that nutrient and/or dry-matter intake and body condition may interact to modify hypothalamic opioidergic activity and thus influence the pulsatile release of LH during the early post-partum period and during the oestrous cycle. Experiment 1 involved 16 multiparous, twin-suckling beef cows, and was a 2 × 2 × 2 factorial design in which the factors were level of post-partum energy intake (80 v. 130 M) metabolizable energy (ME) per day), the digestible undegradable protein (DUP) content of the post-partum diet (14 v. 31 g/kg dry matter), and treatment with either 200 mg or 400 mg naloxone hydrochloride. Blood samples were collected at 15-min intervals for 4h at weeks 4 and 7 post partum. Naloxone was administered intravenously after the eighth sample. Experiment 2 involved 16 cyclic maiden heifers and was also arranged in a factorial manner, with two levels of body condition at the start of the experimental period (2·50 and 3·16 units) and two levels of energy intake thereafter (40 and 80 MJ ME per day). Seven blood samples were collected at 15-min intervals on 4 days consecutively during the mid-luteal phase of the oestrous cycle. On the first 2 of these 4 days naloxone was administered, whilst on the last 2 days a gonadotropin-releasing hormone agonist (buserelin; GnRH) was administered, both after the fourth sample. Plasma from both experiments was assayed for LH and prolactin (Prl).In experiment 1, cows on 130 MJ ME per day returned to oestrus and ovulated earlier than cows on 80 MJ ME per day (44·5 v. 55·0 days; s.e.d. = 3·93; P < 0·05). At week 4 post partum the proportional increase in plasma LH following naloxone challenge was greater for cows on 130 MJ ME per day than cows on 80 MJ ME per day (1·38 v. 1·12; P < 0·05), but the converse was true at week 7 (1·15 v. 1·68; P < 0·05). Cows on the high DUP diet required a higher dose of naloxone to elicit an LH response. Few heifers in experiment 2 exhibited an LH response to naloxone. In contrast, there were significant dietary treatment effects on the LH response to GnRH (P < 0·01). Relatively thin heifers on 40 MJ ME per day exhibited the lowest proportional increases in plasma LH to GnRH challenge, whereas heifers on 80 MJ ME per day and given the higher dose of GnRH produced the greatest plasma LH responses. Mean Prl concentrations before and after feeding in experiment 2 were respectively 13·2 and 10·2 ng/l (P < 0·01).Suckled cows given a high energy diet during the early post-partum period can overcome the opioid mediated block on LH release and resume oestrous cycles earlier than cows given a low energy diet. LH would appear to be inhibited by a non-opioid mechanism in mid-luteal phase heifers. Total pituitary reserves ofLH may be influenced by the animals nutritional status.

scholarly journals The effect of dietary protein on reproduction in the mare. V. Endocrine changes and conception during the early post partum period

1998 ◽  
Vol 69 (3) ◽  
Author(s):  
F.E. Van Niekerk ◽  
C.H. Van Niekerk
Keyword(s):  
Dietary Protein ◽  
Luteal Phase ◽  
Essential Amino Acid ◽  
Post Partum ◽  
Oestrous Cycle ◽  
Protein Diet ◽  
High Quality ◽  
Treatment Groups ◽  
High Quality Protein ◽  
Post Partum Period

Pregnant Anglo-Arab and Thoroughbred mares (n = 24) were divided randomly according to age and breed into 4 groups of 6 mares each from approximately 6 weeks before their expected foaling date. Diets received by the 4 groups varied in essential amino-acid and total protein contents. Serum progestagen, FSH and LH concentrations were determined from the day of parturition until foal heat and during the 1st oestrous cycle following foal heat. Serum progestagen, FSH and LH concentrations did not differ between the treatment groups. Progestagen concentrations were high (c = 7.0: 5.2-16.4 ng/mℓ) at parturition but decreased rapidly within 48 h. As progestagen concentrations decreased LH concentrations increased from Days 3-6 post partum to reach maximum values at, or the day after ovulation. FSH concentrations declined 3-4 d after parturition and increased 2-3 d before ovulation at foal heat. The duration of elevated progestagen concentrations during the luteal phase of the subsequent oestrous cycle affected the interovulatory period. A 12-14 d FSH cyclical releasing pattern occurred. Season/photoperiod affected the resumption of normal oestrous cyclicity during the post partum period. The duration of the 1st oestrous cycle after foal heat in mares fed a low-quality protein diet showed a greater range (13-30 d) compared to mares fed a high-quality protein diet (18-26 d).

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