scholarly journals Peri-ovulatory endocrine regulation of the prostanoid pathways in the bovine uterus at early dioestrus

2017 ◽  
Vol 29 (3) ◽  
pp. 544 ◽  
Author(s):  
Milena Lopes Oliveira ◽  
Fabio Luiz D'Alexandri ◽  
Guilherme Pugliesi ◽  
Veerle Van Hoeck ◽  
Fernando Silveira Mesquita ◽  
...  
Keyword(s):  
Prostaglandin F2α ◽  
Transcript Abundance ◽  
Beef Cows ◽  
Corpora Lutea ◽  
Endocrine Regulation ◽  
Uterine Tissue ◽  
Ovulatory Follicle ◽  
Endocrine Profile ◽  
Prostaglandin Endoperoxide Synthase ◽  
Ovulatory Follicles

We hypothesised that different endocrine profiles associated with pre-ovulatory follicle (POF) size would impact on uterine prostanoid pathways and thereby modulate the histotroph composition. Beef cows (n = 15 per group) were hormonally manipulated to have small (SF-SCL group) or large (LF-LCL group) pre-ovulatory follicles (POF) and corpora lutea (CL). Seven days after induction of ovulation, animals were slaughtered and uterine tissues and flushings were collected for quantification of prostanoids. The POF and CL size and the circulating progesterone concentrations at Day 7 were greater (P < 0.05) in the LF-LCL cows than in the SF-SCL group, as expected. The abundance of 5 out of 19 genes involved in prostanoid regulation was different between groups. Transcript abundance of prostaglandin F2α, E2 and I2 synthases was upregulated (P < 0.05) and phospholipase A2 was downregulated (P < 0.05) in endometrium of the LF-LCL group. No difference (P > 0.1) in prostanoid concentrations in the endometrium or in uterine flushings was detected between groups. However, prostaglandin F2α and E2 concentrations in the uterine flushings were positively correlated with the abundance of transcripts for prostaglandin endoperoxide synthase 2 (0.779 and 0.865, respectively; P < 0.002). We conclude that endometrial gene expression related to prostanoid synthesis is modulated by the peri-ovulatory endocrine profile associated with POF size, but at early dioestrus differences in transcript abundance were not reflected in changes in prostanoid concentrations in the uterine tissue and fluid.

199 The effect of different doses of follicle-stimulating hormone during superovulation on ovarian function in dairy cattle

2019 ◽  
Vol 31 (1) ◽  
pp. 224
Author(s):  
K. Karl ◽  
F. Jimenez-Krassel ◽  
E. Gibbings ◽  
K. E. Latham ◽  
J. J. Ireland
Keyword(s):  
Ovarian Reserve ◽  
Ovarian Function ◽  
Prostaglandin F2α ◽  
Antral Follicle ◽  
Ovulation Rate ◽  
Corpora Lutea ◽  
Ovulatory Follicle ◽  
Study Results ◽  
Ovulatory Follicles ◽  
Higher Doses

Cattle with an unknown antral follicle count (AFC) during follicular waves respond to different FSH doses during superovulation in a curvilinear fashion with the highest doses decreasing or not increasing ovulatory follicle number, number of transferable embryos, and number of corpora lutea (CL). These observations support the hypothesis that heifers treated with different FSH doses during superovulation will reach a superovulation maximum (SOVmax) and that doses exceeding SOVmax are excessive, resulting in a decrease in ovarian function. To test this hypothesis, we used eight 12-month-old Holstein heifers with a low AFC (&lt;10 follicles ≥3mm in diameter, index for small ovarian reserve). These 8 heifers were subjected to 4 different superovulations with a 21-day intervals between each superovulation. During each superovulation, which began on Day 1 of a synchronized oestrous cycle before selection of a dominant follicle, 2 of the 8 heifers were treated (twice-daily FSH injections×4 days) with 20, 40, 80, or 120mg of Folltropin-V (Vetoquinol, Lure, France). At the end of the study, the same 8 heifers had been superovulated 4 times with each of the 4 FSH doses. To enhance ovulation rate in response to hCG, each superovulated heifer was injected with 3 different injections of prostaglandin F2α (PGF2α) spaced 12h apart to induce luteolysis of the original CL. Two PGF2α injections were given after each FSH injection on the last day of FSH treatment and the last PGF2α injection was given after the hCG (2500IU) injection, which was 12h after the last FSH injection. Daily ultrasonography was used to measure AFC and number of ovulatory follicles and CL during the study. Results of t-test analysis showed that at time of hCG, AFC was greater (P&gt;0.05) for heifers treated with the 40-mg (mean±s.e.m., 27±3.7) v. 20-mg (17.9±2.5) FSH dose, but the response to higher FSH doses (27.9±4.4; 27±3.3) did not differ from the response to the 40-mg dose. Number of ovulatory follicles was greater (P&lt;0.05) for heifers treated with the 40-mg (17.5±2.3) v. 20-mg (10.1±1.4) FSH dose, but the response to higher doses (18.9±3.3; 17.3±2.4) did not differ from the response to the 40-mg dose. At Day 7 post-hCG, CL number was greater (P&lt;0.05) for heifers treated with the 40-mg (13.8±2.9) v. 20-mg (7.4±1.4) dose, but response to higher doses (9.9±3.2; 9.1±2.3) did not differ from the response to the 40-mg dose. Ovulation rate (ovulatory follicle number divided by CL number) was greater (P&lt;0.05) for heifers treated with the 40-mg (79±0.08%) v. 80-mg (52±0.09%) or 120-mg (53±0.09%) dose, but similar to that of heifers treated with 20-mg (73±0.09%) FSH dose. These results support the conclusion that the 40-mg FSH dose achieves SOVmax and FSH doses greater than SOVmax in cattle with a low AFC and small ovarian reserve are excessive and detrimental to ovarian function. This project was supported by Agriculture and Food Research Initiative Competitive Grant no. 2017-67015-26084 from the USDA National Institute of Food and Agriculture (Washington, DC).

scholarly journals Negative impact of high doses of follicle-stimulating hormone during superovulation on the ovulatory follicle function in small ovarian reserve dairy heifers†

2020 ◽  
Author(s):  
Kaitlin R Karl ◽  
Fermin Jimenez-Krassel ◽  
Emily Gibbings ◽  
Janet L H Ireland ◽  
Zaramasina L Clark ◽  
...  
Keyword(s):  
Ovarian Reserve ◽  
Assisted Reproductive Technologies ◽  
Negative Impact ◽  
Follicle Stimulating Hormone ◽  
Prostaglandin F2α ◽  
Reproductive Technologies ◽  
Corpora Lutea ◽  
Ovulatory Follicle ◽  
High Doses ◽  
Stimulating Hormone

Abstract When women with small ovarian reserves are subjected to assisted reproductive technologies, high doses of gonadotropins are linked to high oocyte and embryo wastage and low live birth rates. We hypothesized that excessive follicle-stimulating hormone (FSH) doses during superovulation are detrimental to ovulatory follicle function in individuals with a small ovarian reserve. To test this hypothesis, heifers with small ovarian reserves were injected twice daily for 4 days, beginning on Day 1 of the estrous cycle with 35, 70, 140, or 210 IU doses of Folltropin-V (FSH). Each heifer (n = 8) was superovulated using a Williams Latin Square Design. During each superovulation regimen, three prostaglandin F2α injections were given at 12-h interval, starting at the seventh FSH injection to regress the newly formed corpus luteum (CL). Human chorionic gonadotropin was injected 12 h after the last (8th) FSH injection to induce ovulation. Daily ultrasonography and blood sampling were used to determine the number and size of follicles and corpora lutea, uterine thickness, and circulating concentrations of estradiol, progesterone, and anti-Müllerian hormone (AMH). The highest doses of FSH did not increase AMH, progesterone, number of ovulatory-size follicles, uterine thickness, or number of CL. However, estradiol production and ovulation rate were lower for heifers given high FSH doses compared to lower doses, indicating detrimental effects on ovulatory follicle function.

EFFECTS OF PROSTAGLANDIN F2α ON SOME REPRODUCTIVE PROCESSES OF HAMSTERS AND RATS

1972 ◽  
Vol 53 (2) ◽  
pp. 201-213 ◽  
Author(s):  
A. P. LABHSETWAR
Keyword(s):  
Prostaglandin F2α ◽  
Concomitant Administration ◽  
Corpora Lutea ◽  
Fallopian Tubes ◽  
Racemic Form ◽  
Endocrine Profile ◽  
Prostaglandin F ◽  
Blue Reaction ◽  
Egg Transport ◽  
Reproductive Processes

SUMMARY In an attempt to characterize the endocrine profile of prostaglandin F2α (PGF2α) in relation to the female reproductive system, the compound (racemic form) was administered to hamsters and rats in various reproductive states. The prostaglandin terminated pregnancy when given once a day either subcutaneously (50 μg/hamster) or orally (1·5–2 mg/hamster) from Days 4 to 6 of pregnancy inclusive, or as a single subcutaneous injection (50 μg/animal) on Day 4. In the rat, higher (500 μg/injection) and more frequent (twice daily) s.c. injections were required to get even foetal resorption. Concomitant administration of progesterone (4 mg/animal) in either species protected pregnancy. Prostaglandin F2α terminated pregnancy without interfering with the Pontamine blue reaction, suggesting that its antifertility effects were not mediated by inhibition of implantation. In both hamsters and rats the prostaglandin markedly reduced the size of deciduomata which could be restored to normal by administration of progesterone. Prostaglandin F2α delayed passage of zygotes through the Fallopian tubes in a proportion of rats but failed to accelerate egg transport in rats and hamsters. Furthermore, it caused a marked histological degeneration of the corpora lutea and induced formation of a fresh set of corpora lutea in pseudopregnant, pregnant and pseudopregnant—hysterectomized hamsters. These deleterious effects of prostaglandin were accompanied, in hamsters, by the appearance of freshly ovulated tubal ova. Most of the endocrine effects of PGF2α observed in this study can be accounted for by its luteolytic property.

147 EFFECT OF OVULATORY FOLLICLE DIAMETER ON THE OOCYTE TRANSCRIPTOME IN BEEF COWS

2016 ◽  
Vol 28 (2) ◽  
pp. 203
Author(s):  
S. E. Dickinson ◽  
J. A. Green ◽  
T. W. Geary ◽  
K. G. Pohler ◽  
G. A. Bridges ◽  
...  
Keyword(s):  
Zinc Finger ◽  
Zinc Finger Protein ◽  
Transcript Abundance ◽  
Beef Cows ◽  
Fetal Mortality ◽  
Physiological Status ◽  
Oocyte Competence ◽  
Follicle Diameter ◽  
Ovulatory Follicle ◽  
Prostaglandin F

Inadequate oocyte competence is a potential explanation for reduced pregnancy rates and(or) embryonic/fetal mortality when small dominant follicles are induced to ovulate prematurely with gonadotropin releasing hormone (GnRH). Our hypothesis was that the physiological status of an ovulatory follicle has a direct effect on competence of the oocyte and resulting embryo. The objective was to determine if the transcriptome of oocytes differ depending on whether they are collected from small or large dominant follicles following a GnRH-induced gonadotropin surge. Suckled beef cows (n = 350) were pre-synchronized with a 5-day CIDR protocol. Following pre-synchronization, GnRH1 was administered on Day –9, prostaglandin F on Day –2, GnRH2 (to initiate the ovulatory process) on Day 0, and dominant follicles were transvaginally aspirated on Day 1 before follicular rupture. On Day 0, cows were divided into small (<11.7 mm; no oestrus expression), or large (>12.5 mm; no oestrus expression) groups based on dominant follicle diameter. Oocytes were individually collected after aspiration, and RNA was later extracted from pools of 4 oocytes (n = 6 oocyte pools from both small and large follicles) and sequenced on an Illumina HiSEqn 2000 (single reads, 100 bases; Illumina Inc., San Diego, CA, USA). The sequences were tiled against a ~23 500 member bovine transcript reference obtained from the National Center for Biotechnology Information (http://www.ncbi.nlm.nih.gov/). Tiling to target transcripts required a minimum match of 50 bases with at least 96% identity. Tiling counts were displayed as reads per kilobase of transcript per million mapped reads (RPKM) values, which were obtained by correcting for the length of each target (in kb) and the number of total tiled reads (in millions). Differences between groups were defined by two-tailed t-test and gene lists were selected based on P-values <0.02. Numerous differences in transcript abundance were characterised between oocytes from small and large dominant follicles. Follistatin-like 5 expression was increased (P < 0.02) in oocytes collected from large dominant follicles compared with oocytes collected from small dominant follicles. Several genes were associated with the ubiquitin pathway (e.g. ubiquitin conjugating enzyme, ubiquitin like protein-7) and were up-regulated (P < 0.02) in oocytes from large versus small dominant follicles. In addition, 4 members of the zinc finger protein family were up-regulated (P < 0.02) and 4 members were down-regulated (P < 0.02) in oocytes from large compared with small dominant follicles. In summary, some of the genes that were highly differentially regulated in bovine oocytes between small and large dominant follicles included members of the zinc finger and ubiquitin pathways, which may reflect differences in transcriptional regulation and protein turnover, respectively, between oocytes collected from large and small follicles. Study was supported by AFRI Grant no. 2013–67015–21076 from the USDA National Institute of Food and Agriculture (Washington, DC).

224 EFFECT OF LENGTHENING THE SUPERSTIMULATORY TREATMENT PROTOCOL ON THE OVARIAN RESPONSE AND NUMBERS OF TRANSFERABLE EMBRYOS IN BEEF COWS

2012 ◽  
Vol 24 (1) ◽  
pp. 224
Author(s):  
A. Garcia Guerra ◽  
A. Tribulo ◽  
J. Yapura ◽  
J. Singh ◽  
R. J. Mapletoft
Keyword(s):  
Total Dose ◽  
Collection Efficiency ◽  
Animal Health ◽  
Treatment Protocol ◽  
Prostaglandin F2α ◽  
Ovarian Response ◽  
Beef Cows ◽  
Control Group ◽  
Corpora Lutea ◽  
Significant Difference

The present study was designed to test the hypothesis that an increase in the length of exposure of ovulatory follicles to progesterone and FSH during ovarian superstimulation will increase the number of ovulations and viable embryos in cattle. Twenty-four beef cows were initially subjected to follicle ablation at random stages of the oestrous cycle to determine the number of follicles at wave emergence; cows with comparable numbers of follicles were randomly allocated to groups by replicate. A single dose of prostaglandin F2α (PGF; Estroplan, Vétoquinol, QC, Canada) was given IM 7 to 9 days after follicle ablation and daily ultrasound examinations were performed to detect ovulation. Follicular ablation of all follicles ≥5 mm was done 5 to 8 days after ovulation and a progesterone-releasing intravaginal device (PRID, Vétoquinol) was inserted. The Control group (n = 12) was treated with 4 days of FSH and cows in the Long group (n = 12) were given 7 days of FSH treatment. The FSH treatments were initiated 1.5 days after ablation (Day 0) with a total dose of 400 mg of NIH-FSH-P1 (Folltropin-V; Bioniche Animal Health, Belleville ON, Canada). The total dose of FSH was distributed equally over 8 (Control) or 14 (Long) IM injections at 12-h intervals. Prostaglandin F2α was administered twice (at 12-h intervals) on Day 2 (Control) or Day 5 (Long) and PRID were removed 12 h after the last PGF. Both groups received 25 mg of porcine LH (pLH) IM (Lutropin-V; Bioniche Animal Health) 24 h after PRID removal and AI with frozen–thawed semen of proven fertility was done 12 and 24 h later. A third AI was done 12 h later in cows with 2 or more follicles ≥9 mm (12/12 and 9/12 in Control and Long groups, respectively; P = 0.22). All animals were subjected to transrectal ultrasonography every other day and at the time of ova or embryo collection. Ova or embryos were collected nonsurgically 7 days after the pLH injection and evaluated following IETS guidelines. Embryos were defined as transferable (Grades 1, 2 and 3) and freezable (Grades 1 and 2). Procedure Genmod was used to compare variables between treatments and results are presented as means ± SEM (Table 1). There was no significant difference in the total numbers of ova/embryos recovered, but there were more ovulations, corpora lutea (CL), fertilized ova and transferable and freezable embryos in the Long group (P < 0.05). Collection efficiency (number of ova/embryos over the number of CL) was lower in the Long group (P < 0.05). In summary, lengthening of the superstimulatory treatment resulted in an increased number of ovulations without a decrease in oocyte or embryo competence. Data suggest that the traditional 4-day superstimulatory treatment protocol provides inadequate time to maximize ovulatory response. Table 1.Superovulatory response (mean ± SEM) of cows subjected to a conventional 4-day (Control) or a 7-day (Long) treatment protocol

315 RETURN TO ESTRUS AND OVULATION FOLLOWING ADMINISTRATION OF PROSTAGLANDIN IN SUPEROVULATED BEEF COWS

2013 ◽  
Vol 25 (1) ◽  
pp. 304 ◽  
Author(s):  
J. Garzon ◽  
M. Ramos ◽  
A. Tribulo ◽  
G. A. Bó
Keyword(s):  
Single Injection ◽  
Prostaglandin F2α ◽  
Beef Cows ◽  
Corpora Lutea ◽  
Dominant Follicle ◽  
Chi Square ◽  
Luteal Regression ◽  
Chi Square Test ◽  
The Mean ◽  
Donor Cows

Two experiments were designed to evaluate the effect of administering 1 or 2 doses of prostaglandin F2α (PGF) at the time of ova/embryo collection on luteal regression and return to oestrus and ovulation in donor cows. In Experiment 1, 14 Angus cows were blocked at the time of embryo collection by the number of corpora lutea (CL) determined by rectal palpation [6 to 10 CL (n = 6), 11 to 15 CL (n = 4), >15 CL (n = 4)] and were randomly assigned to 2 groups to receive a single injection of 500 µg of sodium cloprostenol (PGF, Ciclase, Syntex S.A., Buenos Aires, Argentina) on the day of embryo collection (Day 0) or a single injection of PGF on Day 0 and a second injection of PGF 24 h later. All cows were bled daily to determine progesterone concentrations by RIA and ultrasonically scanned daily (Falco 100, Pie Medical, Maastricht, the Netherlands) for 19 days after embryo collection, to determine ovulation of a newly recruited dominant follicle. In Experiment 2, 47 superovulated Angus cows were blocked by CL numbers [1 to 4 CL (n = 5), 5 to 10 (n = 11), 11 to 15 (n = 13), >15 CL (n = 18)] and treated as in Experiment 1. In this experiment, cows were bled and scanned on Days 0 (i.e. embryo collection), 4, 7, 10, 13, 16, and 19. The interval from embryo collection to luteal regression (i.e. plasma progesterone <1 ng mL–1) and to ovulation was analysed using ANOVA. Proportions were compared by Chi-square test. In Experiment 1, the mean (± SEM) number of CL in donor cows was 11.9 ± 2.0, and the effect of CL numbers on luteal regression, oestrus, and ovulation was not significant (P > 0.5). The interval from treatment to luteal regression was not affected by PGF treatment (1 PGF: 2.0 ± 1.2 days; 2 PGF: 2.4 ± 1.0 days). Furthermore, 6/7 animals (85.7%) were observed in oestrus in both groups, and 6/7 (85.7%) and 4/7 (57.1%) ovulated within 19 days in the 1 PGF and 2 PGF groups, respectively (P > 0.2). The interval to oestrus and ovulation did not differ among groups (7.0 ± 0.7 days and 8.5 ± 0.6 days v. 9.7 ± 0.5 days and 10.0 ± 0.7 days, for 1 PGF and 2 PGF, respectively; P > 0.1). In Experiment 2, the mean number of CL in donor cows did not differ from that in Experiment 1 (13.9 ± 1.1; P > 0.37), and the effect of CL numbers on luteal regression and ovulation was not significant (P > 0.7). Although luteal regression occurred earlier (P = 0.03) in the 2 PGF group (4.1 ± 0.6 days) compared with the 1 PGF group (5.3 ± 2.2 days), no differences were detected between PGF groups in any of the other parameters. The proportion of cows in oestrus and the interval to oestrus was 19/24 (79.2%) and 7.2 ± 0.4 days v. 18/23 (78.3%) and 7.2 ± 0.3 days for cows in the 1 PGF and 2 PGF groups, respectively (P > 0.7). Finally, the proportion of cows ovulating within 19 days after collection and the interval to ovulation were 20/24 (83.3%) and 10.3 ± 0.4 days v. 21/23 (91.3%) and 10.1 ± 0.4 days for cows in the 1 PGF and 2 PGF groups, respectively (P > 0.4). In summary, treatment with PGF at the time on embryo collection results in luteal regression in 4 to 5 days and ovulation of a new dominant follicle in 80 to 90% of the donors within 19 days. The addition of a second PGF treatment did not shorten the interval to oestrus and ovulation.

166 Comparison of the 7 and 7 Synch protocol and the 7-day CO-Synch + controlled internal drug release protocol among recipient beef cows in an embryo transfer programme

2020 ◽  
Vol 32 (2) ◽  
pp. 210
Author(s):  
R. C. Bonacker ◽  
K. R. Gray ◽  
C. A. Breiner ◽  
J. M. Anderson ◽  
D. J. Patterson ◽  
...  
Keyword(s):  
Drug Release ◽  
Embryo Transfer ◽  
Body Condition Score ◽  
Prostaglandin F2α ◽  
Beef Cows ◽  
Corpora Lutea ◽  
Frozen Embryos ◽  
Condition Score ◽  
Recommended Guidelines ◽  
Mixed Groups

An experiment was designed to evaluate the effectiveness of the recently developed 7 and 7 Synch protocol to synchronise oestrus and ovulation among recipients before embryo transfer (ET). Postpartum beef cows (n=1358) across 13 locations were assigned to either the 7-day CO-Synch + controlled internal drug release (CIDR) protocol or the 7 and 7 Synch protocol before oestrus detection and subsequent ET. Cows were pre-assigned to balanced treatments within location based on age and days postpartum, and body condition score was recorded at ET. Cows assigned to the 7-day CO-Synch + CIDR protocol were administered gonadotrophin-releasing hormone (GnRH; 100µg of gonadorelin acetate) on Day 0, an intravaginal CIDR insert (1.38g of progesterone) from Day 0 to 7, and prostaglandin F2α (PG; 25mg of dinoprost tromethamine) coincident with CIDR removal on Day 7. Cows assigned to the 7 and 7 Synch protocol were administered PG (25mg of dinoprost tromethamine) coincident with CIDR insertion on Day −7, GnRH (100µg of gonadorelin acetate) on Day 0, and PG (25mg of dinoprost tromethamine) coincident with CIDR removal on Day 7. The 7 and 7 Synch protocol was hypothesised to enhance response to GnRH administration on Day 0 among mixed groups of oestrous cycling and anestrous cows, ultimately resulting in improved oestrous response and synchrony of oestrus before ET. Cows were observed for visible signs of oestrus following oestrus synchronisation, with GnRH (100µg of gonadorelin acetate) administered to cows failing to express oestrus during the detection period. Length of the detection period varied among locations but was consistent across treatments within location. Embryo transfer was performed approximately 7 days after oestrus or GnRH administration. Presence of corpora lutea (CL) was determined via transrectal palpation by a single veterinarian blinded to treatment, and embryos were transferred only to cows with palpable CL. Embryo transfer was performed using fresh or frozen embryos staged and graded according to IETS recommended guidelines, with embryo information recorded for each recipient. Data were analysed using the PROC GLIMMIX procedure of SAS (SAS Institute Inc.). Proportion of cows expressing oestrus was improved (P&lt;0.0001) among cows assigned to the 7 and 7 Synch protocol (86% (529/615) vs. 76% (488/640)). The proportion of recipient females with palpable CL tended to be greater (P=0.07) among cows assigned to the 7 and 7 Synch protocol (82% (478/586) vs. 80% (451/565)). Among cows that expressed oestrus, a greater proportion (P&lt;0.01) had palpable CL following the 7 and 7 Synch protocol (88% (466/529) vs. 86% (418/488)). Consequently, irrespective of embryo type received, the proportion of recipients pregnant to ET was greater (P&lt;0.01) following the 7 and 7 Synch protocol (39%; 263/668) compared with the 7-day CO-Synch + CIDR protocol (33%; 228/690). In summary, the 7 and 7 Synch protocol improved the likelihood of oestrus expression in recipient cows, increased the proportion eligible to receive an embryo, and resulted in greater pregnancy rate to ET.

scholarly journals Correlation between Pre-Ovulatory Follicle Diameter and Follicular Fluid Metabolome Profiles in Lactating Beef Cows

Metabolites ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 623
Author(s):  
Casey C. Read ◽  
Lannett Edwards ◽  
Neal Schrick ◽  
Justin D. Rhinehart ◽  
Rebecca R. Payton ◽  
...  
Keyword(s):  
Follicular Fluid ◽  
Cumulus Cells ◽  
Beef Cows ◽  
Pathway Enrichment Analysis ◽  
Induced Ovulation ◽  
Follicle Diameter ◽  
Ovulatory Follicle ◽  
Altered Glucose ◽  
Embryo Cleavage ◽  
Ovulatory Follicles

Induced ovulation of small pre-ovulatory follicles reduced pregnancy rates, embryo survival, day seven embryo quality, and successful embryo cleavage in beef cows undergoing fixed-time artificial insemination. RNA-sequencing of oocytes and associated cumulus cells collected from pre-ovulatory follicles 23 h after gonadotropin-releasing hormone (GnRH) administration to induce the pre-ovulatory gonadotropin surge suggested reduced capacity for glucose metabolism in cumulus cells of follicles ≤11.7 mm. We hypothesized that the follicular fluid metabolome influences metabolic capacity of the cumulus-oocyte complex and contributes to reduced embryo cleavage and quality grade observed following induced ovulation of small follicles. Therefore, we performed a study to determine the correlation between pre-ovulatory follicle diameter and follicular fluid metabolome profiles in lactating beef cows (Angus, n = 130). We synchronized the development of a pre-ovulatory follicle and collected the follicular contents approximately 20 h after GnRH administration. We then performed ultra-high performance liquid chromatography—high resolution mass spectrometry (UHPLC-HRMS) metabolomic studies on 43 follicular fluid samples and identified 38 metabolites within pre-ovulatory follicles of increasing size. We detected 18 metabolites with a significant, positive correlation to follicle diameter. Individual and pathway enrichment analysis of significantly correlated metabolites suggest that altered glucose and amino acid metabolism likely contribute to reduced developmental competence of oocytes when small pre-ovulatory follicles undergo induced ovulation.

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