scholarly journals The effect of GnRH or oestradiol injected at pro-oestrus on luteal function and follicular dynamics of the subsequent oestrous cycle in non-lactating cycling Holstein cows

2006 ◽  
Vol 73 (1) ◽  
Author(s):  
B.V.E. Segwagwe ◽  
K.L. MacMillan ◽  
P.D. Mansell
Keyword(s):  
Corpus Luteum ◽  
Optimum Concentration ◽  
New Wave ◽  
Luteal Function ◽  
Future Studies ◽  
Induction Of Ovulation ◽  
Follicular Wave ◽  
Oestradiol Benzoate ◽  
Lower Fertility ◽  
Follicular Dynamics

Oestrous synchronization involves synchronization of ovarian follicular turnover, new wave emergence, and finally induction of ovulation. The final step can be synchronized by the parenteral administration of either GnRH or oestradiol benzoate. This study investigated corpus luteum and follicular emergence after ovulation had been induced by the administration of either GnRH or oestradiol benzoate. The injection of oestradiol benzoate may have delayed the emergence of the first follicular wave subsequent to the induced ovulation; administration of oestradiol benzoate or GnRH lowered the progesterone rise so that the maximum dioestrous concentration of progesterone on Day 9 was lower when cows were treated during pro-oestrus compared to the spontaneously ovulating controls. One implication of findings from the present study is that induction of ovulation with either oestradiol benzoate or GnRH, administered 24 or 36 h after withdrawal of the CIDR device, respectively, may lower fertility. Future studies must identify the timing of administration relative to the time of CIDR device withdrawal and the optimum concentration of oestradiol benzoate or GnRH that would not have untoward effects on the development of the corpus lutea, particularly within the first week of dioestrus.

Induction of ovulation with GnRH or oestradiol benzoate lowers plasma progesterone concentration within the first week of ovulation in non-lactating Holstein cows

2003 ◽  
Vol 2003 ◽  
pp. 1-1
Author(s):  
B.V.E. Segwagwe ◽  
K.L. Macmillan ◽  
P.D. Mansell
Keyword(s):  
Comparative Study ◽  
Corpus Luteum ◽  
Holstein Cows ◽  
New Wave ◽  
Progesterone Concentration ◽  
Plasma Progesterone ◽  
Induction Of Ovulation ◽  
Follicular Wave ◽  
Oestradiol Benzoate

Oestrous synchronisation involves synchronisation of ovarian follicular turnover, new wave emergence, and finally induction of ovulation which can be achieved with an injection of either GnRH (Pursley et al. 1997)or oestradiol benzoate (ODB) (Day et al. 2000). A comparative study investigating corpus luteum (CL) and follicular emergence after the administration of either GnRH or ODB at pro-oestrus has not been reported. It was hypothesised that the injection of ODB at pro-oestrus would delay emergence of the first post-ovulatory follicular wave, but that CL development and plasma progesterone concentrations would be similar in cows induced to ovulate with either GnRH or ODB.

THE MECHANISM OF THE INDUCTION OF OVULATION BY OESTROGENS

1965 ◽  
Vol 33 (3) ◽  
pp. 491-499 ◽  
Author(s):  
F. DÖCKE ◽  
G. DÖRNER
Keyword(s):  
Effective Dose ◽  
Corpus Luteum ◽  
Anterior Pituitary ◽  
Anterior Hypothalamus ◽  
Female Rats ◽  
Main Site ◽  
Induction Of Ovulation ◽  
Gonadotrophin Secretion ◽  
Oestradiol Benzoate ◽  
Electrolytic Lesions

SUMMARY To study the positive feed-back mechanism by which oestrogen induces corpus luteum formation, electrolytic lesions were placed in different parts of the anterior hypothalamus of prepubertal female rats which were then injected with oestradiol benzoate. Ovarian luteinization did not occur when the main parts of the suprachiasmatic nuclei or of the medial preoptic area had been destroyed. Oestradiol benzoate was implanted stereotaxically into the brain and the anterior pituitary of immature female rats. Whereas 1/25 of the subcutaneously effective dose had to be implanted into the anterior hypothalamus, 1/100 of the peripherally effective dose introduced into the adenohypophysis was sufficient to induce corpus luteum formation in most of the treated animals. The results suggest that, although the anterior hypothalamus is necessary for this positive feed-back mechanism, the anterior pituitary may be the main site of action of oestrogen. Oestrogen may increase the hypophysial sensitivity to the hypothalamic gonadotrophin-releasing factor. Thus an enhanced gonadotrophin secretion may result, sufficient for the induction of ovulation. The possibility is discussed that this positive feed-back mechanism is also essential for the induction of ovulation in women.

scholarly journals The use of a ‘first-wave’ model to study the effect of nutrition on ovarian follicular dynamics and ovulation rate in the sheep

Reproduction ◽  
2010 ◽  
Vol 140 (6) ◽  
pp. 865-874 ◽  
Author(s):  
C Viñoles ◽  
B Paganoni ◽  
K M M Glover ◽  
J T B Milton ◽  
D Blache ◽  
...  
Keyword(s):  
Body Condition ◽  
Wave Model ◽  
Ovulation Rate ◽  
Short Term ◽  
Metabolic Hormones ◽  
Follicular Waves ◽  
Follicular Wave ◽  
The Third ◽  
High Concentrations ◽  
Follicular Dynamics

We have developed an experimental model in which groups of ewes are simultaneously experiencing the first ovarian follicular wave of their oestrous cycle. We used this ‘first-wave model’ in a 2×2 factorial experiment (ten ewes per group) to study the effect of body condition (BC) and a short-term supplement on follicular dynamics and ovulation rate. The ‘first-wave’ was established by giving ewes three injections of prostaglandin (PG), 7 days apart. The 6-day supplement (lupin grain) began 2 days after the second PG injection and continued until the third. Follicles were studied by ultrasound, and blood was sampled to measure glucose and hormones. The supplement increased (P<0.01) the concentrations of glucose, insulin and leptin, decreased FSH concentrations (P<0.01) and tended to increase oestradiol concentrations (P=0.06). The supplement tended to increase the number of 3 mm follicles (P=0.06). Compared with low-BC ewes, high-BC ewes had more follicular waves (P<0.05), higher concentrations of insulin, leptin and IGF1 (P<0.05) and tended to have higher FSH concentrations (P=0.09). Leptin and insulin concentrations remained high until the end of supplementation in high-BC ewes, whereas they decreased after the third day of supplementation in low-BC ewes. In conclusion, high concentrations of metabolic hormones in fat ewes are associated with the development of more follicular waves. When a supplement is superimposed on this situation, changes in glucose and metabolic hormones allow more follicles to be selected to ovulate.

scholarly journals Ovarian Follicular Dynamics during the Estrous Cycle in Jennies in Upper Egypt

2011 ◽  
Vol 2011 ◽  
pp. 1-6 ◽  
Author(s):  
R. I. Derar ◽  
H. A. Hussein
Keyword(s):  
Growth Rate ◽  
Estrous Cycle ◽  
Slow Rate ◽  
Ovarian Follicles ◽  
Maximum Diameter ◽  
Dominant Follicle ◽  
Upper Egypt ◽  
Follicular Wave ◽  
Preovulatory Follicles ◽  
Follicular Dynamics

The objective of the current study was to describe follicular dynamics in Egyptian Jennies throughout the estrous cycle. In this experiment, 8 estrus cycles in 8 cyclic Jennies were studied from February to June using ultrasonography. The result revealed that one follicular wave per cycle was recorded throughout the studied period. Dominant follicle (DF) was firstly detected at day in Jennies. The growth rate of DF was  mm/day. Left ovulations were nonsignificantly () more than right ovulations (55.6% versus 44.6%). The CL was firstly detected at D , developed in a rate of  mm/day, reached a maximum diameter of  mm at D , and started to regress on D with a mean regression rate of  mm d-1. Results of the present study indicated that Jennies had one follicular wave per cycle. The Day of the cycle has a significant effect on the number of different classes of the ovarian follicles, but not large ones. Ultrasonographic characteristics of the preovulatory follicles could be useful to predict ovulation. CL developed and regressed in a slow rate.

GONADAL HORMONES AND THE CONTROL OF OVULATION IN THE GUINEA-PIG

1972 ◽  
Vol 55 (3) ◽  
pp. 599-607 ◽  
Author(s):  
B. T. DONOVAN ◽  
A. N. LOCKHART
Keyword(s):  
Guinea Pig ◽  
Corpus Luteum ◽  
Acute Treatment ◽  
Gonadal Hormones ◽  
Time Of Day ◽  
Gonadal Steroids ◽  
Corpora Lutea ◽  
Plasma Progesterone ◽  
Gonadotrophin Secretion ◽  
Oestradiol Benzoate

SUMMARY The release of ovulating hormone after acute treatment with gonadal steroids, or corpus luteum removal on different days of the oestrous cycle, was studied in the guinea-pig. Injection of 25, 50 or 100 μg oestradiol or 2·5 mg progesterone on day 13 of the cycle had no effect upon gonadotrophin secretion as judged by follicular histology, but markedly altered the sizes of the corpora lutea of the previous ovulation. Treatment with oestradiol on day 14 did not elicit gonadotrophin secretion. However, administration of the same hormones to animals given 10 μg oestradiol benzoate 24 h earlier caused ovulation or follicular luteinization. Progesterone (2·5 mg) appeared least effective in stimulating gonadotrophin release; 25 μg oestradiol were more effective when given at 12.00 h than at 24.00 h but treatment with both hormones caused ovulation when given at either time of day. Luteal volumes were not affected. Removal of corpora lutea during the second half of the cycle advanced the time of expected ovulation to day 15 or earlier when the procedure was carried out on days 8 or 9, but not on days 10–13. It is concluded that 4–5 days must elapse between the fall in plasma progesterone level associated with corpus luteum regression and the release of ovulating hormone.

Oxytocin receptor concentrations, inositol phosphate turnover and prostaglandin release by endometrium from ewes induced to ovulate during the early post-partum period

1993 ◽  
Vol 136 (1) ◽  
pp. 17-NP ◽  
Author(s):  
J. M. Wallace ◽  
M. G. Thompson ◽  
R. P. Aitken ◽  
M. A. Cheyne
Keyword(s):  
Receptor Binding ◽  
Inositol Phosphate ◽  
Post Partum ◽  
Oxytocin Receptor ◽  
Receptor Expression ◽  
Luteal Function ◽  
Induction Of Ovulation ◽  
Release Device ◽  
Prostaglandin F

ABSTRACT Induction of ovulation early post partum in sheep is associated with a high incidence (30–40%) of premature luteolysis. The present study was designed to characterize oxytocin receptor levels, oxytocin-stimulated inositol phosphate (IP) turnover (second messenger) and oxytocin-stimulated prostaglandin F2α (PGF2α) release in the endometrium of post-partum ewes induced to ovulate 21 days after parturition and expected to exhibit a range of corpus luteal functions subsequently. Ovulation was induced on day 21 post partum using a controlled internal drug release device and pregnant mare serum gonadotrophin, and uterine tissues were collected on days 5, 10 or 15 of the cycle (n = 4/day). A further 12 ewes whose interval from previous parturition exceeded 150 days were similarly treated and acted as controls. Measurement of daily peripheral progesterone concentrations revealed that while all control ewes exhibited normal luteal function, abnormal luteal function was evident in two, two and one post-partum ewes studied on days 5, 10 and 15 of the cycle respectively. Oxytocin receptor binding was detected (by receptor-binding assay and in-vitro autoradiography) in the endometrium and myometrium of post-partum ewes at all three stages of the oestrous cycle but only at day 15 in control ewes. To determine IP turnover, 100 mg caruncular endometrium was incubated in duplicate for 2·5 h with 10 μCi [3H]inositol and treated with 0 or 2 μmol oxytocin/l for 30 min, then [3H]inositol mono-, bis- and trisphosphates were quantified. Oxytocin stimulated total IPs in all day-5 and day-15 post-partum ewes, in three of four day-10 ewes and in all day-15 control ewes. Basal endometrial PGF2α release measured in triplicate (100 mg/well) during a 2 h incubation was higher in post-partum versus control ewes on days 5 and 10 but not on day 15 of the cycle. Similarly, oxytocin stimulated PGF2α release to varying levels at all stages of the cycle in post-partum ewes but only on day 15 in control ewes. Irrespective of the treatment group endometrial oxytocin receptor number was significantly (P < 0·001) correlated with oxytocin-stimulated IP turnover and PGF2α release. Thus the induction of ovulation and the subsequent luteal phase in post-partum ewes is against a back ground of high oxytocin receptor expression and enhanced PGF2α release which in some ewes may contribute to abnormal luteal function. Journal of Endocrinology (1993) 136, 17–25

Studies on Ovarian Follicular Dynamics and Steroid Profiles in Sahiwal Cattle

2021 ◽  
Author(s):  
Vinny Dodiyar ◽  
Parkash Singh Brar ◽  
Narinder Singh ◽  
Mrigank Honparkhe
Keyword(s):  
Corpus Luteum ◽  
Estrous Cycle ◽  
Maximum Diameter ◽  
Endocrine Regulation ◽  
Dominant Follicle ◽  
Estrous Cycles ◽  
Significant Difference ◽  
Sahiwal Cattle ◽  
Sahiwal Cows ◽  
Follicular Dynamics

Background: Understanding of ovarian follicular dynamics and endocrine regulation is essential to design and use interventions to optimize reproductive efficiency. Bos indicus and Bos taurus cows have some differences in their follicular dynamics and ovarian steroidal hormones. The present study was planned to understand follicular dynamics vis-a-vis ovarian steroids profiles in Sahiwal cattle. Methods: The study was conducted in normal cyclic, pluriparous, non-lactating Sahiwal cows (n=7). Trans-rectal ultrasonography was performed to record the location, size, number of follicles and size of corpus luteum (CL) from the beginning, till the end of experiment. The dataset was used to characterize the follicular wave emergence, growth, regression, time of selection and ovulation of the dominant follicle in each cow. Result: Three Sahiwal cows showed two wave and four cows showed three wave estrous cycles with mean interovulatory length of 20.33±0.33 and 22.50±0.28 days, respectively. No significant difference was recorded in the maximum diameter of corpus luteum, P4 and E2 plasma levels between 2-wave and 3-wave estrous cycles. The peak progesterone values of 6.00±0.91 and 6.2±1.2 ng/ml and peak estradiol values of 15.83±0.60 and 14.31±0.44 ng/ml were recorded in 2-wave and 3-wave estrous cycle, respectively. The results showed that Sahiwal cows had 2-wave and 3-wave estrous cycle and the 3-wave estrous cycle had comparatively longer inter-ovulatory period and smaller maximum diameter of second wave dominant follicle than 2-wave estrous cycle.

Blood perfusion and diameter of bovine corpus luteum as predictors of luteal function in early pregnancy

2021 ◽  
Author(s):  
Gabriella dos Santos Velho ◽  
Monique Tomazele Rovani ◽  
Rogério Ferreira ◽  
Bernardo Garziera Gasperin ◽  
André Gustavo Cabrera Dalto
Keyword(s):  
Corpus Luteum ◽  
Early Pregnancy ◽  
Blood Perfusion ◽  
Luteal Function ◽  
Bovine Corpus Luteum
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