240 RELATIONSHIP BETWEEN PEAK NUMBER OF ANTRAL FOLLICLES AND FOLLICULAR WAVES, HORMONE CONCENTRATIONS, SUPEROVULATORY RESPONSE, AND EMBRYO QUALITY IN BEEF HEIFERS

2006 ◽  
Vol 18 (2) ◽  
pp. 228 ◽  
Author(s):  
F. Ward ◽  
P. Lonergan ◽  
F. Jimenez-Krassel ◽  
J. J. Ireland ◽  
A. C. O. Evans
Keyword(s):  
Recovery Rate ◽  
Embryo Quality ◽  
Corpora Lutea ◽  
Beef Heifers ◽  
High Group ◽  
Estrous Cycles ◽  
Antral Follicles ◽  
Peak Number ◽  
Follicular Waves ◽  
The Mean

Recent studies in dairy cattle demonstrate that the number of antral follicles during follicular waves is highly variable among animals, but highly repeatable within individuals, and the numbers of follicles during waves are inversely associated with serum FSH concentrations (Burns et al. 2005 Biol. Reprod. 73, 54-62). The aims of this study were to determine (1) serum FSH and estradiol concentrations during follicular waves in beef heifers categorized according to peak number of antral follicles per wave, and (2) the relationship between this categorization and superovulatory response. Estrous cycles of crossbred beef heifers (n = 90) were synchronized with two i.m. injections of PGF2� 11 days apart; animals were scanned daily for 5 days beginning 24 h after the second PG injection to determine the number of follicles during the first follicle wave in two or three consecutive estrous cycles. Heifers were grouped based on the peak number of follicles e 3 mm per wave in diameter (Low: d 15 follicles, n = 12; High: e 25 follicles, n = 11). Intermediate animals were excluded. Heifers were then re-synchronized and blood samples taken every 8 h up to Day 7 to characterize FSH and estradiol profiles. Subsequently, animals were superovulated (pFSH, Folltropin�; Bioniche Animal Health, Belleville, Ontario, Canada), inseminated, and flushed on Day 7; this procedure was repeated twice. All values for hormone concentrations were aligned relative to the peak FSH value. A mixed model, repeated-measures approach was used to determine if serum FSH and estradiol concentrations were different between groups. Differences in recovery rate (number of oocytes/embryos recovered compared to number of corpora lutea) and proportion of transferable embryos were analyzed using Chi-square analysis. The mean (�SE) peak postovulatory FSH concentration was lower (P d 0.03) for animals with high numbers of follicles. No differences in estradiol concentrations were observed. The mean superovulatory response (number of corpora lutea) was higher (P d 0.05) in the High group than in the low group (17.6 � 3.6 vs. 8.5 � 1.1). While there was no difference in the recovery rate of embryos (62 vs. 60%), significantly more (P d 0.05) oocytes/embryos (10.6 � 2.7 vs. 4.7 � 0.7) and transferable embryos (5.4 � 1.3 vs. 3.8 � 0.8) were recovered per animal in the High group. Of the embryos recovered, the proportion of transferable quality was higher for animals in the Low group (80 vs. 51%; P d 0.05). In conclusion, the number of antral follicles during a follicular wave in beef heifers is inversely related to peak postovulatory FSH concentration, but is unrelated to estradiol concentration. In addition, while the superovulatory response and number of transferable embryos were greater in animals with a high number of antral follicles, embryo quality, measured as the proportion of transferable embryos per donor, was reduced. We conclude that cattle with relatively high numbers of follicles per wave respond best to standard superovulation protocols. However, the reason the proportion of high quality embryos is reduced in cattle with high vs. low numbers of follicles per wave is unknown.

233 ANTI-MÜLLERIAN HORMONE AS A PREDICTIVE ENDOCRINE MARKER FOR SUPEROVULATORY RESPONSE AND EMBRYO PRODUCTION IN BEEF CATTLE

2016 ◽  
Vol 28 (2) ◽  
pp. 248
Author(s):  
K. Center ◽  
D. Dixon ◽  
R. Rorie
Keyword(s):  
Beef Cattle ◽  
Blood Sample ◽  
Beef Cows ◽  
Corpora Lutea ◽  
Embryo Production ◽  
Antral Follicles ◽  
Stage Of Development ◽  
The Mean ◽  
Donor Cows

A study investigated the use of anti-Müllerian hormone (AMH) and/or follicle counts as a predictor of subsequent superovulatory response and embryo production in 79 beef cows. Before initiation of superovulation, ultrasonography was used to scan the ovaries of each donor cow to record the number of 3 to 5 mm follicles present, and a blood sample was collected for measure of serum AMH. At the time of embryo collection, the ovaries of donor cows were palpated to estimate the number of corpora lutea (CL) present on each ovary. Recovered embryos were evaluated for stage of development and morphological quality. Across cows, serum AMH ranged from 0.013 to 0.898 ng mL–1, with a mean of 0.293 ng mL–1. The distribution of AMH concentrations was divided into quartiles (AMH Q1 through Q4, with Q1 the lowest and Q4 the highest, ng mL–1) for analysis (ANOVA). Number of donors/collections in AMH Q1 through Q4 was 26, 22, 24, and 24, respectively. Donor cows in AMH Q4 had a greater (P < 0.001) number of 3- to 5-mm follicles at the start of superovulation than did donors in either Q1 or Q2. At embryo collection, cows in AMH Q3 and 4 had more (P < 0.001) palpable CL than cows in AMH Q1. The mean number of embryos recovered from donor cows in AMH Q4 (20.1 ± 1.8) was greater (P < 0.001) than those recovered from cows in either AMH Q1 (9.8 ± 1.8) or 2 (9.4 ± 1.9), but similar to that of AMH Q3 (15.5 ± 1.8). Percentages of recovered embryos classified as transferrable, degenerate, or unfertilized were similar (P ≥ 0.275) across AMH quartiles. Analysis indicated that AMH was positively correlated (P < 0.001) with mean follicles (r = 0.458), CL (r = 0.452), and embryos recovered (r = 0.430). To determine if follicle counts at the start of superovulation are predictive of superovulatory response, the distribution of follicle counts was divided into quartiles (F Q1 through Q4, with Q1 the lowest and Q4 the highest) for analysis. Donor cows with higher follicle counts (F Q3 and 4) at the start of superovulation had more (P < 0.001) palpable CL at embryo collection than donor cows in F Q1 or 2. More (P < 0.001) embryos (20.0 ± 2.2 v. 9.6 ± 1.8 and 11.6 ± 1.6) were recovered from cows with the highest follicle counts (F Q4) compared with cows having lower (F Q1 and 2) follicle counts, respectively. The percentage of transferable embryos and unfertilized ova were similar (P ≥ 0.688) across follicle count quartiles. As was noted for AMH, mean number of follicles at the start of superovulation was positively correlated (P < 0.001) with mean CL (r = 0.556) and mean embryos (r = 0.423) but not percentages of viable or degenerate embryos or unfertilized oocytes (P ≥ 0.153). Results confirm that relative AMH concentration was positively correlated with number of small antral follicles in the ovaries of cows and might be used to either predict superovulatory response or possibly adjust superovulatory regimen to improve superovulatory response. Further study is needed to determine the effectiveness of using either AMH concentration or follicle counts to adjust superovulatory regimens.

Effects of cloprostenol and flurogestone acetate sponge on embryo yields and quality in indigenous ewes in Bangladesh

2014 ◽  
Vol 54 (10) ◽  
pp. 1605 ◽  
Author(s):  
B. F. Zohara ◽  
Azizunnesa ◽  
M. F. Islam ◽  
M. G. S. Alam ◽  
F. Y. Bari
Keyword(s):  
Recovery Rate ◽  
Group Iv ◽  
Corpora Lutea ◽  
Group Iii ◽  
Embryo Recovery ◽  
Fertilisation Rate ◽  
Group I ◽  
The Mean ◽  
Group Ii ◽  
Mean Time

The effects of two doses of cloprostenol and two doses of flurogestone acetate sponge on the onset of oestrus, and embryo recovery and quality were evaluated. Thirty-two indigenous ewes (Wera breed) were allocated into four groups of eight. All ewes were synchronised with 100 µg (Group I) or 175 µg (Group II) cloprostenol injection, 9 days apart, or insertion of intravaginal sponges containing 30 mg (Group III) or 45 mg (Group IV) flurogestone acetate (FGA) for 12 days. The ewes were superovulated with 600 IU PMSG intramuscularly 10 days after the second cloprostenol injection or immediately after sponge removal on Day 12. After the detection of oestrus, the ewes were mated naturally at 6 and 12 h, and some ewes were inseminated laparoscopically. Embryos were recovered surgically 5 or 6 days after service. All ewes exhibited oestrus. The onset of oestrus occurred significantly (P < 0.05) earlier in FGA-treated (50.0 ± 1.5 and 48.0 ± 0.00 h) than in cloprostenol-treated groups. There were no significant differences (P > 0.05) in the mean time of onset of oestrus (50.0 ± 1.5 and 48.0 ± 0.00 h) between the two doses of cloprostenol. The mean number of corpora lutea (8.1 ± 1.26) and embryos recovered (6.1 ± 1.00) was significantly (P < 0.05) higher in ewes treated with 45 mg FGA than in ewes treated with cloprostenol. Embryo recovery rate was significantly (P < 0.05) higher in ewes treated with 45 mg FGA (75.4%) than in other groups (41.7% and 51.6% in 100 μg and 175 μg cloprostenol- and 52.7% in 30 mg FGA-treated groups, respectively). Fertilisation rate was 93.3% in ewes given 100 µg cloprostenol, whereas other groups showed 100% fertilisation rate. The highest percentage (100%) of Grade 1 embryos was in FGA groups. In conclusion, despite FGA protocol presenting superior results, cloprostenol protocol was equally efficient in synchronising oestrus. The embryo recovery rate was better after 45 mg FGA than 30 mg FGA or after either dose of cloprostenol.

183 EXERCISE INFLUENCES EMBRYO QUALITY IN MARES

2010 ◽  
Vol 22 (1) ◽  
pp. 250 ◽  
Author(s):  
R. Smith ◽  
K. Vernon ◽  
J. Gibbons ◽  
D. Kelley ◽  
J. Anton ◽  
...  
Keyword(s):  
Recovery Rate ◽  
Embryo Quality ◽  
Exercise Group ◽  
Quality Score ◽  
Control Group ◽  
Recovery Rates ◽  
Embryo Recovery ◽  
Humid Environment ◽  
Negative Effect ◽  
The Mean

Athletic mares are commonly utilized in an embryo transfer regimen during the breeding season, which allows owners to continue to train and compete with these animals. Exercising mares in a hot and humid environment has proven detrimental to embryo recovery rates. However, the effects of exercise under milder temperatures have not been examined. Our goal was to compare embryo recovery rates and embryo quality scores of mares under mild environmental conditions of 2 differing exercise regimens v. a single control group (n = 5). One treatment group (full exercise) consisted of mares (n = 5) exercised 6 days a week throughout the duration of the project. The partial-exercise group (n = 5) was exercised throughout the duration of the project 7 days a week, with full rest from day of detected ovulation to the proceeding embryo collection attempt. This was to limit any deleterious effects exercise may potentially have on the mare and subsequent early developing equine embryo. Exercise resumed the day after an embryo collection attempt for the partial-exercise group. Exercised mares were given a 1-month training period prior to the beginning of this project and were moderately exercised for 30 min in a mechanical exercise pen (free exerciser). Control mares were managed similarly as the other groups, however were not exercised. Mares were bred via artificial insemination and embryos were nonsurgically collected 7 d post-ovulation. Mean environmental temperature during the duration of this study was 27.1°C with average 60% humidity. Immediately following completion of exercise, mares in the full exercise group had a mean temperature increase of 1.0°C and partial-exercised mares increased 0.9°C. Exercise had a significant effect on embryo quality (P < 0.05, Table 1) but did not influence embryo recovery rate. The mean embryo quality score for the control group was 1.1, whereas the full-exercised group was 1.85 and partial-exercised group was 2.5. It appears from these data that exercise has a negative effect on embryo quality, thus lowering the availability of transferable embryos. Embryos of lower quality (≥3) have been shown to result in poor pregnancy rates in horses. Additionally, rest from ovulation to an embryo collection attempt did not improve embryo quality. Table 1.Embryo recovery rate and quality score of embryos from control and exercised mares

scholarly journals Ovarian Expression of Insulin-Like Peptide 3 (INSL3) and Its Receptor (RXFP2) During Development of Bovine Antral Follicles and Corpora Lutea and Measurement of Circulating INSL3 Levels During Synchronized Estrous Cycles

Endocrinology ◽  
2013 ◽  
Vol 154 (5) ◽  
pp. 1897-1906 ◽  
Author(s):  
Leanne Satchell ◽  
Claire Glister ◽  
Emma C. Bleach ◽  
Richard G. Glencross ◽  
Andrew B. Bicknell ◽  
...  
Keyword(s):  
Granulosa Cell ◽  
Major Product ◽  
Corpora Lutea ◽  
Potential Contribution ◽  
Mrna Levels ◽  
Estrous Cycles ◽  
Lh Surge ◽  
Antral Follicles

Abstract Insulin-like peptide 3 (INSL3), a major product of testicular Leydig cells, is also expressed by the ovary, but its functional role remains poorly understood. Here, we quantified expression of INSL3 and its receptor RXFP2 in theca interna cell (TIC) and granulosa cell compartments of developing bovine antral follicles and in corpora lutea (CL). INSL3 and RXFP2 mRNA levels were much higher in TIC than granulosa cell and increased progressively during follicle maturation with INSL3 peaking in large (11-18 mm) estrogen-active follicles and RXFP2 peaking in 9- to 10-mm follicles before declining in larger (11-18 mm) follicles. Expression of both INSL3 and RXFP2 in CL was much lower than in TIC. In situ hybridization and immunohistochemistry confirmed abundant expression of INSL3 mRNA and protein in TIC. These observations indicate follicular TIC rather than CL as the primary site of both INSL3 production and action, implying a predominantly autocrine/paracrine role in TIC. To corroborate the above findings, we showed that in vitro exposure of TIC to a luteinizing concentration of LH greatly attenuated expression of both INSL3 and its receptor while increasing progesterone secretion and expression of STAR and CYP11A1. Moreover, in vivo, a significant cyclic variation in plasma INSL3 was observed during synchronized estrous cycles. INSL3 and estradiol-17β followed a similar pattern, both increasing after luteolysis, before falling sharply after the LH surge. Thus, theca-derived INSL3, likely from the dominant preovulatory follicle, is detectable in peripheral blood of cattle, and expression is down-regulated during luteinization induced by the preovulatory LH surge. Collectively, these findings underscore the likely role of INSL3 as an important intrafollicular modulator of TIC function/steroidogenesis, while raising doubts about its potential contribution to CL function.

An evaluation of the success of MOET in two breeds of hill sheep maintained under normal systems of hill flock management

1999 ◽  
Vol 69 (2) ◽  
pp. 367-376 ◽  
Author(s):  
F. Bari ◽  
M. Khalid ◽  
W. Haresign ◽  
B. Merrell ◽  
A. Murray ◽  
...  
Keyword(s):  
Recovery Rate ◽  
Embryo Quality ◽  
Survival Rates ◽  
Negative Relationship ◽  
Embryo Survival ◽  
Factors Affecting ◽  
Embryo Recovery ◽  
Multiple Ovulation ◽  
Middle Range ◽  
The Mean

AbstractThis study was undertaken to investigate factors affecting the success of multiple ovulation and embryo transfer (MOET) in Scottish Blackface (no. = 120) and Welsh Mountain (no. = 120) ewes, over a period of 2 years using a laparoscopic procedure for both embryo recovery and transfer. Superovulation was induced with ovine FSH, with 98 to 100% of ewes of both the breeds responding to the treatment. The overall mean superovulatory responses were 15⋅0 (s.e. 0⋅8) and 12⋅5 (s.e. 0⋅7) for Scottish Blackface and 15⋅3 (s.e. 0⋅9) and 12·8 (s.e. 0⋅8) for Welsh Mountain ewes in years 1 and 2, respectively. However, there was a wide degree of variation in superovulatory responses within each breed, with a range of 3 to 29 in Scottish Blackface and 1 to 40 in Welsh Mountain ewes. The mean embryo recovery rate was 71⋅9 (s.e. 3⋅5) % and 69⋅6 (s.e. 3⋅4) % for Scottish Blackface and 57⋅5 (s.e. 4⋅1) % and 60⋅6 (s.e. 3⋅6) % for Welsh Mountain ewes in years 1 and 2, respectively. The mean number of embryos recovered from Welsh Mountain ewes was significantly (P < 0⋅05) lower than that from Scottish Blackface ewes in both years. The lower mean number of embryos recovered in year 2 for both breeds was entirely a reflexion of the lower superovulatory responses in year 2. A significant (P < 0⋅001) relationship was observed between superovulatory response and the number of embryos recovered for both breeds. Some 77% and 72% of Scottish Blackface ewes and 65% and 73% of Welsh Mountain ewes yielded four or more transferable embryos in years 1 and 2, respectively. Neither the mean number nor the mean percentage of transferable embryos per donor ewe differed between breeds or years. A significant (P < 0⋅001) negative relationship was observed between the time of onset of oestrus and both superovulatory response and number of embryos recovered in Scottish Blackface ewes only. Embryo quality was affected by the time of onset of oestrus. In both breeds, the highest proportion of grade 1+2 embryos and the lowest proportion of unfertilized/degenerate embryos occurred in the middle range time, with a reduction in the proportion of grade 1+2 embryos in ewes that came into oestrus either early <19 h) or late (>30 h) after sponge removal. Only one embryo was transferred to each recipient and the embryo survival rates were 76⋅8% and 74⋅6% (Scottish Blackface), and 69⋅6% and 87⋅3% (Welsh Mountain) for years 1 and 2, respectively. Overall the results of this study suggest that MOET is as successful in hill ewes as has been reported for lowland breeds, even without making any major concessions to their hill status.

scholarly journals Ovarian follicular dynamics in Boran and Crossbred heifers in Ethiopia: Implications for assisted reproductive techniques

2020 ◽  
Vol 24 (2) ◽  
pp. 54-72
Author(s):  
Jeilu Jemal ◽  
Tamrat Degefa ◽  
Tefera Yilma ◽  
Sayid Ali ◽  
Lemma Alemayehu
Keyword(s):  
Recovery Rate ◽  
Ovarian Follicle ◽  
Reproductive Potential ◽  
Progesterone Level ◽  
Maximum Diameter ◽  
Serum Progesterone ◽  
Estrous Cycles ◽  
Follicular Waves ◽  
Follicular Dynamics

The study was conducted to characterize the follicular dynamics of purebred Boran (Bos indicus) and Boran * Holstein Friesian crossbred heifers  during estrous cycles; for use in ovum pick up and in-vitro embryo production. Insight of reproductive physiology of cattle would help to understand and exploit the reproductive potential of elite animals for breed improvement. Follicular development, growth and atresia during estrous cycles were evaluated using a trans-rectal real-time B-mode ultrasound system for three consecutive estrus cycles. Luteal activity was evaluated by serum progesterone level. Follicular aspirations were done to investigate the potential of Boran cattle and their crosses for transvaginal oocyte production; using a vacuum pressure pump and Aloka SSD Prosound-2 ultrasound device. Boran heifers (n=15) manifested two (n = 6, 40%), three (n = 5, 33%), four (n= 3, 20%) and five (n=1, 6.7%) follicular waves. Crossbred heifers (n=14) showed one (n= 2, 14%), two (n= 6, 43%) and three (n= 6, 43%) follicular waves. Interovulatory interval was 21.1 ± 3.4 and 21.4 ± 2.7 days for Boran (n=45) and crossbred (n=42) heifers, respectively. The progesterone level in Boran and Crossbred heifers during diestrus was 9.5 ± 11.0 and 4.6 ± 8.8 ng/ml, respectively. The maximum diameter of the ovulatory follicle for crossbred heifers was higher (15.4 ± 1.6 mm) than the diameter of the Boran (14.0 ± 1.9 mm) heifers (p<0.005). Differences (p<0.005) were observed in the size of both right (26.6 ± 5.14 and 28.6 ± 5.1 mm) and left (21.7 ± 4.85 and 24.1 ± 5.07 mm) ovaries of Boran and Crossbred heifers, respectively. Difference (p<0.005) was also observed in follicular count of the  right ovaries of Boran (4.84 ± 1.96) and Crossbred  (5.13 ± 2.05) heifers. Oocyte recovery rate in once weekly collection scheme for Boran and their crossbred heifers was (n=19, 42.08%) and (n=17, 42.55%), respectively. The recovery rate for twice weekly collection scheme was (n=24, 34.53%) and (n=23, 40.44%) for Boran and crossbred heifers, respectively. Follicular dynamics in Boran heifers is characterized by a higher incidence of cycles with two, three and four waves, associated with a low persistence of the dominant follicles; and smaller size of ovulatory follicles and less intense heat signs from their crossbred counterpart. Boran heifers proved to have potential for comparable number of follicular population and ease of aspiration procedures that can be tapped for advancedreproductive techniques. Keywords: Estrus cycle; follicular wave; ovarian follicle; ovum pickup; ultrasound.

76 Effect of season on the superstimulation response, embryo quality, and pregnancy establishment in dromedary camel (Camelus dromedarius)

2021 ◽  
Vol 33 (2) ◽  
pp. 146
Author(s):  
H. A. Abouhefnawy ◽  
N. A. Wani
Keyword(s):  
Breeding Season ◽  
Embryo Quality ◽  
Treatment Protocol ◽  
Uterine Horn ◽  
Dromedary Camel ◽  
Corpora Lutea ◽  
Dromedary Camels ◽  
Nonbreeding Season ◽  
Single Intramuscular Injection ◽  
The Mean

The present study was conducted to study the effect of season on the superstimulation response, embryo quality and pregnancy establishment in the dromedary camels. Two donors each were superstimulated in the month of June 2019 (non-breeding season) and January 2019 (breeding season) by a combination of 2500IU of equine chorionic gonadotrophin (eCG, Folligon; Intervet), given as a single intramuscular injection on Day 1 of the treatment protocol, and 400mg of pFSH (Folltropin; Bioniche) injected twice daily in declining doses of 2×80mg, 2×60mg, 2×40mg, and 2×20mg over 4 days, also beginning on Day 1. They were scanned by rectal ultrasonography and follicles counted before mating with a fertile bull on Day 11 after the start of treatment. An injection of 20µg of gonadotrophhin-releasing hormone (Receptal, Intervet) was given immediately after mating to induce ovulation. The number of corpora lutea (CL) were counted, and the embryos collected by the non-surgical method on Day 7 after ovulation. All embryos were washed and graded before they were transferred individually into the left uterine horn of recipient animals, synchronized to be on Day 6 after ovulation. All recipients were screened by ultrasonography on Day 22, Day 60, and Day 90 for pregnancies. The data were analysed using a two-sample t-test (Minitab statistical software, Minitab Ltd.). No difference was observed in the mean number of follicles developed (20.5 vs. 18.5) between the donors in breeding and non-breeding season, respectively. The percent mean±s.e.m. of ovulations as observed by counting the CL in nonbreeding season (80.7±3.4) were not different from those in breeding season (85.4±3.7). A total number of 16 embryos collected during non-breeding season and 20 embryos in breeding season were transferred to recipients. The percent mean±s.e.m. of pregnancies established on Day 22 (56.6±3.4 vs. 67.5±7.5) and on Day 90 (47.2±2.8 vs. 60±0.0) were similar in both groups. These observations indicate that embryo transfer technology can be applied to camels during the summer months, which is considered the non-breeding season, and pregnancies can be established at par with breeding season. In conclusion, to the best of our knowledge, this is the first study in camels wherein we have demonstrated that donor camels can be superstimulated, embryos can be collected, recipient animals can be synchronized, and pregnancies can be established in the summer (non-breeding) months. The embryos collected from elite donors can be transferred to synchronized recipients to establish pregnancies or preserved for future use. Some owners do not want calves to be born in summer months, so protocols need to be established for storing these embryos for a few months before their transfer to recipients, to have the calves delivered in the desired winter months.

scholarly journals Effect of immunization against the alpha N (alphaN) and alpha C (alphaC) peptides of the alpha43 subunit of inhibin on antral follicular growth and atresia and the patterns of gonadotrophin secretion in ewes

Reproduction ◽  
2001 ◽  
pp. 707-718 ◽  
Author(s):  
A Dhar ◽  
BW Doughton ◽  
E Pruysers ◽  
RW Brown ◽  
JK Findlay
Keyword(s):  
Follicular Phase ◽  
Corpora Lutea ◽  
Follicular Growth ◽  
Antral Follicles ◽  
Gonadotrophin Secretion ◽  
Preovulatory Follicles ◽  
Early Follicular Phase ◽  
The Mean ◽  
And Control

The aims of this study were to investigate the role of inhibin in the distribution of healthy and atretic antral follicles and the secretion patterns of gonadotrophins. Ewes were actively immunized against either alphaN or alphaC of the inhibin alpha subunit with a primary injection and three booster injections. The control ewes received adjuvant only. The ovaries were removed either before or at 24 h after hCG administration in a synchronized follicular phase 48 h after removal of intravaginal progesterone pessaries. Morphological observations were made on every fifth section of the complete ovary (one per ewe) stained with haematoxylin and eosin. The mean number of corpora lutea observed per ewe with corpora lutea was not significantly different in ewes immunized against alphaN (2.4; alphaN-immunized ewes) or alphaC (2.6; alphaC-immunized ewes), and control (2.4) ewes, although some corpora lutea appeared cystic in the immunized ovaries. Compared with luteal phase concentrations, mean basal FSH concentrations in the early follicular phase were significantly increased in the alphaC-immunized ewes, similar in alphaN-immunized ewes and reduced in control ewes. No differences were observed in any of the LH parameters. Before hCG treatment, healthy antral follicles > 1 mm in diameter were not observed in any of the 52 follicles in the aC-immunized ewes and were observed in one of 37 follicles from alphaN-immunized ewes compared with 19 of 28 follicles in control ewes (P < 0.0001). For healthy antral follicles < 1 mm in diameter, there were 72 of 85 follicles in the alphaC-immunized ewes, 79 of 81 follicles in the alphaN-immunized ewes and 81 of 82 follicles in the control ewes. Similar results were obtained in healthy antral follicles < 1 mm in diameter at 24 h after hCG administration. In contrast to the control ewes, no healthy preovulatory follicles (> 6 mm in diameter) were observed in alphaN- and alphaC-immunized ewes either before or 24 h after hCG administration. Two newly formed corpora lutea from alphaC-immunized ovaries contained retained oocytes compared with none in control and alphaN-immunized ovaries. In conclusion, immunization against alphaN and alphaC may result in disruption of the normal processes of antral follicular growth and maturation independent of the concentrations of FSH and LH.

Effect of chronic FSH administration on ovarian follicular development, ovulation rate and corpora lutea formation in sheep

1993 ◽  
Vol 138 (2) ◽  
pp. 315-325 ◽  
Author(s):  
K. P. McNatty ◽  
N. L. Hudson ◽  
D. A. Heath ◽  
L. Shaw ◽  
L. Blay ◽  
...  
Keyword(s):  
Granulosa Cells ◽  
Plasma Concentrations ◽  
Ovulation Rate ◽  
Corpora Lutea ◽  
Aromatase Activity ◽  
Treatment Groups ◽  
Antral Follicles ◽  
Linear Relationships ◽  
The Mean

ABSTRACT This study in ewes examined the effects on ovarian function of a pulsatile regimen of ovine FSH (NIADDK-oFSH-17) administered over a 24- to 28-day period beginning on day 1 of the oestrous cycle (day 0 = oestrus). The FSH (1·66 μg or 5·00 μg) was administered i.v. over a 1-min interval once every hour throughout the treatment period. In other ewes ovine LH (NIDDK-oLH-23) was administered (10 μg once every 2 h) for 24–28 days together with oFSH (1·66 μg/h). Compared with untreated controls (n = 19 ewes), FSH alone at both doses (n = 19 ewes/dose) as well as the FSH +LH treatment (n=10) led to significant increases in the plasma concentrations of FSH (P <0·01), ovarian weight (P <0·05) and ovulation rate (P <0·01) but there was no change in the mean weight of individual corpora lutea (CL). Exogenous FSH at the high but not the low dose alone or with LH stimulated a significant overall increase in plasma inhibin concentrations (P <0·05). The geometric mean (and 95% confidence limits) ovulation rates in the high FSH (i.e. 5·00 μg/h), low FSH (i.e. 1·66 μg/h), low FSH+LH, and control treatment groups were 15·3 (9·3, 24·8), 3·7 (2·1, 6·0), 3·7 (2·5, 5·8) and 1·4 (1·2, 1·7) respectively. The FSH or FSH+LH treatments did not alter the total numbers of antral follicles (≥1 mm diameter). However, the high but not the low FSH or low FSH + LH treatment led to significant increases in the mean numbers of large follicles (i.e. >4·5 mm diameter; P<0·01) and a higher proportion of non-atretic antral follicles. Highly significant linear relationships were found between the mean plasma concentrations of FSH or inhibin and the ovulation rate (FSH: r=0·74, P<0·0001; inhibin: r=0·93, P<0·0001). Highly significant linear relationships were also found between the plasma concentrations of FSH or inhibin and the number of large follicles (i.e. >4·5 mm diameter; FSH, r=0·78, P<0·0001; inhibin, r=0·80, P<0·0001) and between the plasma concentrations of inhibin and the number of granulosa cells in large follicles (r=0·78, P<0·0001). After the high FSH but not the low FSH treatment there were significant increases in both FSH- and LH-induced responsiveness in granulosa cells with respect to cyclic AMP synthesis in vitro. In the high FSH treatment group, granulosa cells from 1–2·5 mm diameter follicles were responsive to LH whereas, in the low FSH or FSH + LH treatment groups and the controls, granulosa cells were not responsive to LH until the follicles were >4·5 mm in diameter. FSH or FSH+ LH treatment did not lead to increases in aromatase activity in granulosa cells (i.e. when expressed on a per cell basis) or to increases in oestradiol in follicular fluid. Collectively these results show that chronic increases in plasma FSH concentrations influence, in a dose–responsive manner, the size distribution of antral follicles, the proportion of non-atretic follicles, the number of follicles with peak aromatase activity and the ovulation rate, without altering the total number of antral follicles, the granulosa cell composition of individual follicles or the sizes of individual CL. Exogenous FSH treatment at high but not low doses enhanced the sensitivities of granulosa cells to both FSH and LH in vitro. Increases in plasma FSH also led to higher concentrations of plasma inhibin as a consequence of an increase in the number of large follicles and thus the number of granulosa cells. Journal of Endocrinology (1993) 138, 315–325

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.

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