scholarly journals Ovulation rate and embryo survival in Damline ewes after treatment with bovine follicular fluid in the luteal phase of the oestrous cycle

Reproduction ◽  
1985 ◽  
Vol 75 (1) ◽  
pp. 101-109 ◽  
Author(s):  
J. M. Wallace ◽  
A. S. McNeilly ◽  
D. T. Baird
Keyword(s):  
Follicular Fluid ◽  
Luteal Phase ◽  
Oestrous Cycle ◽  
Ovulation Rate ◽  
Embryo Survival

Changes in the secretion of LH pulses, FSH and prolactin during the preovulatory phase of the oestrous cycle of the ewe and the influence of treatment with bovine follicular fluid during the luteal phase

1988 ◽  
Vol 116 (1) ◽  
pp. 123-135 ◽  
Author(s):  
J. M. Wallace ◽  
G. B. Martin ◽  
A. S. McNeilly
Keyword(s):  
Follicular Fluid ◽  
Luteal Phase ◽  
Pulse Amplitude ◽  
Pulse Frequency ◽  
Ovarian Follicles ◽  
Follicular Phase ◽  
Oestrous Cycle ◽  
Ovulation Rate ◽  
The Other ◽  
Lh Secretion

ABSTRACT It has previously been shown that treatment of ewes with bovine follicular fluid (bFF) throughout the luteal phase of the oestrous cycle lowers plasma levels of FSH but increases the frequency and amplitude of the pulses of LH. Under these conditions, ovarian follicles grow to a maximum diameter of 2·7 mm and have a reduced capacity to release oestradiol. We have examined the nature of the gonadotrophin signals controlling follicular development in the normally cycling ewe and have investigated the effects of previous exposure to bFF on these signals and the follicular responses to them. Control ewes (n = l) were injected i.v. with 9 ml bovine serum and treated ewes were injected with 9 ml bFF, twice daily from days 1 to 10 of the luteal phase (day 0 = oestrus). The ewes were injected with prostaglandin analogue on day 11 of the cycle to induce luteolysis and the gonadotrophin patterns were studied in blood sampled from these animals every 10 min for up to 72 h during the subsequent follicular phase. Following luteolysis (and the end of bFF treatment), LH pulse frequency increased rapidly in both groups and reached 1 pulse/h within 6 h. Thereafter, pulse frequency increased marginally and reached 1 pulse/50 min by the onset of the LH surge. This pattern was not affected by previous treatment with bFF. In the control ewes, the amplitude of the LH pulses did not change significantly following luteolysis or at any time during the follicular phase, while the levels of FSH declined slowly until the onset of the surge. In the treated ewes, on the other hand, there was an immediate increase in both LH pulse amplitude and the concentration of FSH immediately after the end of bFF treatment at luteolysis, and they remained above control levels for 24 and 16 h respectively. Plasma prolactin levels did not appear to change around the time of luteolysis but showed a marked and significant diurnal rhythm (nadir around noon and peak around midnight) in both groups. The concentrations of prolactin were significantly (P<0·001) lower and the preovulatory peak was delayed and reduced in the bFF-treated ewes relative to controls. The onset of oestrus was also significantly (P<0·01) delayed by bFF treatment, but the ovulation rates did not differ between the groups. Furthermore, comparisons within or between groups revealed no significant relationships between any of the variables of plasma LH secretion during the follicular phase and the subsequent ovulation rate. These observations provide a complete description of gonadotrophin patterns during the follicular phase of the ewe and confirm the suggestion that an increase in LH pulse frequency is the major driving force behind the follicular growth that ultimately leads to ovulation. On the other hand, it appears most unlikely that the pattern of LH secretion during the follicular phase has any influence on ovulation rate. The levels of FSH declined in the period leading up to the preovulatory surge, presumably as a consequence of rising peripheral levels of oestrogen (and/or inhibin). We also expected LH pulse amplitude to decline during the follicular phase because it has been proposed that pulse amplitude is also controlled by oestrogen. The absence of any significant fall in amplitude suggests that hypotheses about the control of LH secretion drawn from studies with ovariectomized ewes require further verification in the intact ewe. The effect of bFF on prolactin levels probably reflects the low rates of secretion of oestradiol by the small ovarian follicles in these ewes. J. Endocr. (1988) 116, 123–135

Passively immunizing ewes against inhibin during the luteal phase of the oestrous cycle raises the plasma concentration of FSH

1989 ◽  
Vol 123 (3) ◽  
pp. 383-391 ◽  
Author(s):  
G. E. Mann ◽  
B. K. Campbell ◽  
A. S. McNeilly ◽  
D. T. Baird
Keyword(s):  
Plasma Concentration ◽  
Luteal Phase ◽  
Passive Immunization ◽  
Oestrous Cycle ◽  
Ovulation Rate ◽  
Control Group ◽  
Pituitary Cells ◽  
Marked Rise ◽  
Peripheral Plasma

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

scholarly journals Early Pregnancy in the Ewe: Effects of Oestradiol and Progesterone on Uterine Metabolism and on Embryo Survival

1977 ◽  
Vol 30 (4) ◽  
pp. 279 ◽  
Author(s):  
BG Miller ◽  
NW Moore ◽  
Leigh Murphy ◽  
GM Stone
Keyword(s):  
Embryo Transfer ◽  
Embryo Development ◽  
Early Pregnancy ◽  
Protein Metabolism ◽  
Hormonal Regulation ◽  
Luteal Phase ◽  
Progesterone Receptors ◽  
Oestrous Cycle ◽  
Embryo Survival ◽  
Day Of Embryo Transfer

The hormonal regulation of embryo development during early pregnancy in the ewe has been examined. Ovariectomized ewes received injections of oestradiol (E2) and progesterone (P) according to schedules designed to simulate endogenous ovarian secretion during the luteal phase of the previous oestrous cycle (priming P), around the time of oestrus (oestrous E2 ) and during early pregnancy (maintenance P, maintenance E2)' Embryos were transferred to the ewes on the 4th day after induced oestrus, and ewes were killed at 6 or 13 days after transfer to assess embryo development. Cytosol concentrations of oestradiol 'and progesterone receptors and RNA and protein metabolism in the endometrium and amounts of protein in uterine flushings were examined on the day of embryo transfer and 6 days after transfer.

Comparisons between peripheral progesterone concentrations in cyclic and pregnant Landrace x large White and Meishan gilts

1994 ◽  
Vol 6 (6) ◽  
pp. 777 ◽  
Author(s):  
CJ Ashworth ◽  
AW Ross ◽  
CS Haley
Keyword(s):  
Luteal Phase ◽  
Oestrous Cycle ◽  
Ovulation Rate ◽  
Large White ◽  
Blood Samples ◽  
Breed Differences

Progesterone concentrations were determined in blood samples collected twice daily (at 0900 and 1700 hours) from the day of oestrus (Day 0) until Days 15-24 in ten Landrace x Large White gilts (four cyclic and six pregnant gilts) and eight Meishan gilts (four cyclic and four pregnant gilts). Progesterone concentrations during the early luteal phase tended to be higher in pregnant Meishan gilts than in pregnant Landrace x Large White gilts. Furthermore, when differences in ovulation rate and peak progesterone concentrations were accounted for, maximum progesterone concentrations occurred earlier in Meishan gilts than in Landrace x Large White gilts (P < 0.01); this difference was particularly marked when pregnant animals of the two breeds were compared. In non-mated animals, analyses of the timing and magnitude of progesterone concentrations observed towards the end of the oestrous cycle revealed that the decrease in progesterone concentrations occurred earlier (P < 0.05) in Meishan gilts. Such breed differences in the peripheral progesterone profile may be associated with reduced prenatal mortality, a characteristic of Meishan females.

The follicular microenvironment in low (++) and high (I+B+) ovulation rate ewes

Reproduction ◽  
2020 ◽  
Vol 159 (5) ◽  
pp. 585-599
Author(s):  
Zaramasina L Clark ◽  
Derek A Heath ◽  
Anne R O’Connell ◽  
Jennifer L Juengel ◽  
Kenneth P McNatty ◽  
...  
Keyword(s):  
Follicular Fluid ◽  
Cumulus Cell ◽  
Single Copy ◽  
Oocyte Quality ◽  
Ovulation Rate ◽  
Fluid Composition ◽  
Embryo Survival ◽  
Expression Levels ◽  
Follicular Maturation ◽  
Metabolic Substrates

Ewes with single copy mutations in GDF9, BMP15 or BMPR1B have smaller preovulatory follicles containing fewer granulosa cells (GC), while developmental competency of the oocyte appears to be maintained. We hypothesised that similarities and/or differences in follicular maturation events between WT (++) ewes and mutant ewes with single copy mutations in BMP15 and BMPR1B (I+B+) are key to the attainment of oocyte developmental competency and for increasing ovulation rate (OR) without compromising oocyte quality. Developmental competency of oocytes from I+B+ animals was confirmed following embryo transfer to recipient ewes. The microenvironment of both growing and presumptive preovulatory (PPOV) follicles from ++ and I+B+ ewes was investigated. When grouped according to gonadotropin-responsiveness, PPOV follicles from I+B+ ewes had smaller mean diameters with fewer GC than equivalent follicles in ++ ewes (OR = 4.4 ± 0.7 and 1.7 ± 0.2, respectively; P < 0.001). Functional differences between these genotypes included differential gonadotropin-responsiveness of GC, follicular fluid composition and expression levels of cumulus cell-derived VCAN, PGR, EREG and BMPR2 genes. A unique microenvironment was characterised in I+B+ follicles as they underwent maturation. Our evidence suggests that GC were less metabolically active, resulting in increased follicular fluid concentrations of amino acids and metabolic substrates, potentially protecting the oocyte from ROS. Normal expression levels of key genes linked to oocyte quality and embryo survival in I+B+ follicles support the successful lambing percentage of transferred I+B+ oocytes. In conclusion, these I+B+ oocytes develop normally, despite radical changes in follicular size and GC number induced by these combined heterozygous mutations.

Effect of an inhibitor of 3β-hydroxysteroid dehydrogenase on progesterone concentrations and embryo survival in sheep

1987 ◽  
Vol 112 (2) ◽  
pp. 205-213 ◽  
Author(s):  
C. J. Ashworth ◽  
I. Wilmut ◽  
A. J. Springbett ◽  
R. Webb
Keyword(s):  
Luteal Phase ◽  
Hydroxysteroid Dehydrogenase ◽  
Oestrous Cycle ◽  
Silicone Elastomer ◽  
Progesterone Concentration ◽  
Embryo Survival ◽  
Progesterone Production ◽  
Group 3 ◽  
Group 2 ◽  
Group 1

ABSTRACT The effect of an inhibitor of 3β-hydroxysteroid dehydrogenase on peripheral progesterone concentration during the luteal phase of the oestrous cycle and on embryo survival was determined in sheep. Following administration of 10, 50, 100 or 250 mg epostane (4,5-epoxy-17-hydroxy-4,17,dimethyl-3-oxo-androstane-2-carbonitrile) progesterone concentrations were significantly lower than control levels 4 h after injection, from 2·5 to 22 h, 1·5 to 24 h and 1 to 24 h after injection respectively. There appeared to be no effect on peripheral oestradiol concentrations. Adrenal progesterone production was small and not influenced by epostane treatment. Epostane was administered on day 9 of the oestrous cycle to cause a reduction in progesterone concentrations for approximately 12-18 h on day 9 only (group 1, 250 mg epostane on day 9), or a series of such reductions on 3 consecutive days (group 2, 50 mg epostane on days 9, 10 and 11) or a continuous reduction for 3 days (group 3, 250 mg epostane on days 9, 10 and 11). The proportion of ewes that were pregnant was significantly (P<0·05) lower in ewes treated to give a continuously low progesterone concentration for 3 days than in either controls or ewes in which progesterone concentration was reduced for less than 24 h (in controls and groups 1, 2 and 3 the proportion was 85, 92, 54 and 18% of ewes treated respectively). Embryo survival was not affected by administration of 250 mg epostane on days 9, 10 and 11 if luteal phase levels of progesterone were maintained by insertion of a silicone elastomer implant of the steroid. The proportion of embryos surviving was 72% in controls compared with 78% in the treated animals. J. Endocr. (1987) 112, 205–213

178 IS PROGESTERONE THE DETERMINING REGULATORY FACTOR BEHIND OVULATION RATE IN EWES?

2015 ◽  
Vol 27 (1) ◽  
pp. 180
Author(s):  
J. Sohal ◽  
V. Paravinja ◽  
T. Baby ◽  
M. Murawski ◽  
T. Schwarz ◽  
...  
Keyword(s):  
Luteal Phase ◽  
Oestrous Cycle ◽  
Ovulation Rate ◽  
Antral Follicles ◽  
Follicular Waves ◽  
Lh Pulsatility ◽  
Lh Release ◽  
The Mean ◽  
Number Percentage ◽  
Ovulatory Follicles

Ovarian antral follicles in the ewe grow in an orderly succession, producing 3–4 waves per oestrous cycle. In prolific sheep, some large antral follicles from the second-last wave of the oestrous cycle are added to the ovulatory follicles emerging just before oestrus to give a higher ovulation rate; it is feasible that regression of these follicles is prevented by an increase in serum concentrations of FSH and/or LH pulsatility at pro-oestrus. Prolific sheep tend to have a shorter luteal phase than non-prolific breeds and there is a great deal of evidence that luteal progesterone (P4), in addition to regulating LH release, may govern the secretion of FSH heralding the emergence of follicular waves. The specific purpose of the present experiments was to determine whether or not extending the duration of the luteal phase would alter the ovulation rate in prolific sheep. In both studies, exogenous P4 (7.5 mg ewe–1 IM) was administered on Days 11 and 12 (Day 0 = ovulation) in moderately prolific Rideau Arcott x Polled Dorset (Exp. 1, n = 8) and highly prolific Olkuska ewes (Exp. 2, n = 7), while the equinumerous groups of animals served as controls (CTR). Transrectal ovarian ultrasonography was performed daily and jugular blood samples were drawn twice a day from Day 9 until ovulation. All single-time point observations were compared between groups by Student t-test. Progesterone injections resulted in uniform increments in serum P4 levels in all animals allocated to the treatment (TRT) groups. However, the mean duration of the interovulatory interval did not differ (P > 0.05) between TRT and CTR groups of ewes in both experiments. The mean (± s.e.m.) ovulation rate was 1.6 ± 0.2 v. 3.2 ± 0.4 (Exp. 1; P < 0.001) and 3.2 ± 0.8 v. 4.0 ± 1.0 (Exp. 2; P < 0.05) in TRT v. CTR ewes, respectively. There were no differences in terms of the timing of penultimate and final wave emergence between the two subsets of animals studied in either experiment. The number/percentage of ovulating follicles from the penultimate wave of the interovulatory interval studied was 0.25 ± 0.16 v. 1.75 ± 0.45 (P < 0.01)/25.0 ± 16.4% v. 75.0 ± 16.4% (P < 0.05) in Exp. 1 and 0.50 ± 0.30 v. 1.60 ± 0.40 (P < 0.05)/13.8 ± 9.0% v. 53.4 ± 16.7% (P < 0.05) in Exp. 2, in TRT v. CTR animals, respectively. In summary, administration of P4 at the end of diestrus reduced the incidence of ovulations from the penultimate wave of the oestrous cycle in moderately and highly prolific strains of sheep. Therefore, progesterone appears to be a key endocrine signal governing the ovulation rate in cyclic sheep, presumably by acting directly at the level of the ovary. The present results may pave a way to devising a simple and inexpensive method of controlling lamb productivity in commercial flocks of sheep and fertility in other polyovulatory species.

Patterns of gonadotropin secretion in cyclic Finn ewes selected for and against high ovulation rate

1995 ◽  
Vol 61 (2) ◽  
pp. 251-257 ◽  
Author(s):  
W. Haresign ◽  
A. C. Cooper ◽  
M. Khalid ◽  
J. P. Hanrahan
Keyword(s):  
Luteal Phase ◽  
Pulse Frequency ◽  
Follicular Phase ◽  
Oestrous Cycle ◽  
Ovulation Rate ◽  
Gonadotropin Secretion ◽  
High Line ◽  
Lh Secretion

AbstractA comparison of the patterns of LH and FSH secretion was undertaken in lines of Finn sheep selected for and against high ovulation rate. Mean ovulation rate was significantly higher in the high line ewes (mean 4·1) compared with both the control (mean 2·5) and low line (mean 2·7) ewes (P <0·01). The pre-ovulatory LH peak occurred significantly earlier in the high line ewes (mean 52·1 h) compared with both the control (mean 65·0 h) and low line (mean 59·0 h) ewes (P < 0·05). While mean LH pulse frequency and overall mean LH concentrations were both significantly higher during the follicular compared with the luteal phase of the cycle (P < 0·05), there were no consistent relationships between patterns of pulsatile LH secretion and ovulation rate among the three selection lines. Plasma FSH concentrations remained significantly higher over the entire follicular phase of the oestrous cycle in the high line ewes compared with both the control and low line ewes (P < 0·05). It is suggested that the ovulation rate achieved by high line ewes may be causally related to their higher follicular phase FSH concentrations.

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