scholarly journals Effect of follicular aspiration just before ovulation on corpus luteum characteristics, circulating progesterone concentrations and uterine receptivity in single-ovulating and superstimulated heifers

Reproduction ◽  
2012 ◽  
Vol 143 (5) ◽  
pp. 673-682 ◽  
Author(s):  
L O'Hara ◽  
S Scully ◽  
V Maillo ◽  
A K Kelly ◽  
P Duffy ◽  
...  
Keyword(s):  
Corpus Luteum ◽  
Uterine Receptivity ◽  
Subsequent Formation ◽  
Expected Time ◽  
Follicular Aspiration ◽  
Conceptus Development ◽  
Luteal Tissue ◽  
Follicle Aspiration ◽  
Length And Area

The aim of this study was to investigate, in unstimulated and superstimulated heifers, the effect of follicle aspiration just before ovulation on corpus luteum (CL) development, circulating progesterone (P4) concentrations and the ability of the uterus to support embryo development. Following follicle aspiration or ovulation timed from GNRH administration, CL development was assessed by daily ultrasonography, and CL function was assessed in terms of the capacity to produce P4 and the expression of genes involved in steroidogenesis in luteal tissue. The capacity of the uterine environment to support conceptus development was assessed following transfer and recovery of in vitro-produced embryos. Follicular aspiration just before the expected time of ovulation leads to a significant reduction in CL diameter, CL area and area of luteal tissue. This was associated with a decrease in circulating P4 in both unstimulated and superstimulated heifers. Follicle aspiration leads to a reduction in conceptus length and area on day 14 in unstimulated heifers only. Follicle aspiration leads to a reduction in the expression of LHCGR in luteal tissue from unstimulated heifers compared with those in which the CL formed after ovulation. Superstimulation significantly reduced the expression of STAR in luteal tissue in both ovulated and follicle-aspirated heifers. In conclusion, in stimulated and unstimulated heifers, aspiration of the preovulatory dominant follicle(s) just before expected ovulation interferes with the subsequent formation and function of the CL, in terms of size and P4 output and this, in turn, is associated with a reduced capacity of the uterus to support conceptus elongation in unstimulated heifers.

85 EFFECT OF FOLLICULAR ASPIRATION JUST PRIOR TO OVULATION ON CORPUS LUTEUM CHARACTERISTICS, CIRCULATING PROGESTERONE CONCENTRATIONS AND UTERINE RECEPTIVITY IN SINGLE-OVULATING BEEF HEIFERS

2012 ◽  
Vol 24 (1) ◽  
pp. 155 ◽  
Author(s):  
L. O'Hara ◽  
S. Scully ◽  
V. Maillo-Sevilla ◽  
A. K. Kelly ◽  
P. Duffy ◽  
...  
Keyword(s):  
Corpus Luteum ◽  
Embryo Development ◽  
Prostaglandin F2α ◽  
Uterine Receptivity ◽  
Beef Heifers ◽  
Embryo Survival ◽  
Follicular Aspiration ◽  
Follicle Aspiration ◽  
And Function

Progesterone (P4) has a crucial impact on the transcriptome of the uterine endometrium and the preparation of the uterus to support implantation. The aim of this study was to investigate the effect of follicle aspiration just before ovulation on corpus luteum (CL) development, circulating P4 concentrations and the ability of the uterus to support embryo development and conceptus elongation. We tested the hypothesis that the unavoidable loss of follicular fluid and some granulosa cells during aspiration of the preovulatory follicle would compromise the development and function of the developing CL and that this would be associated with reduced P4 and a poorer uterine environment. Oestrous cycles of crossbred beef heifers were synchronized using an 8-day CIDR treatment with administration of a prostaglandin F2α analogue on the day before CIDR removal to ensure CL regression. Heifers were checked for signs of oestrus 4 times per day commencing 30 h after CIDR withdrawal and only those recorded in standing oestrus (Day 0, n = 20) were used. All heifers received a gonadotropin-releasing hormone agonist (0.01 mg buserelin) 48 h after CIDR removal to induce an LH surge. Half of the animals underwent follicle aspiration 20 h later, while the remainder underwent ovulation. Daily transrectal ultrasonography was carried out from Day 3 to 13 to record CL development. Daily blood samples were collected from Day 0 to 14 for circulating P4 concentrations. To test the ability of the uterus to support embryo development and conceptus elongation, Day 7 in vitro-produced blastocysts were transferred to the uteri of synchronised recipients (7 to 10 blastocysts per recipient). All recipients were slaughtered on Day 14 to assess embryo survival and conceptus size. CL diameter and CL area were significantly reduced in the follicle aspirated group compared with controls from Day 6 onwards (P ≤ 0.05). Similarly, at slaughter on Day 14, CL weight (4.17 ± 0.48 vs 7.05 ± 1.65 mm), diameter (19.89 ± 1.35 vs 24.64 ± 2.07 mm) and area (321.94 ± 45.01 vs 510.18 ± 69.41 mm2) were lower in aspirated heifers (P ≤ 0.05). Circulating P4 concentrations were lower at all time points from Day 3 to Day 14 but were only significantly lower from Day 12 onwards (P ≤ 0.05). Conceptus length (2.08 ± 0.29, n = 56 vs 4.55 ± 0.78 mm, n = 45) and area (2.52 ± 0.39 vs 5.61 ± 1.12 mm2) were lower (P ≤ 0.05) in heifers undergoing follicular aspiration compared with those undergoing ovulation. In conclusion, aspiration of the preovulatory dominant follicle just before expected ovulation was associated with a compromised CL in terms of size and P4 output and this, in turn, was associated with a reduced capacity of the uterus to support the initiation of conceptus elongation. Supported by Science Foundation Ireland (07/SRC/B1156).

Effect of combined exogenous progesterone with luteotrophic support via equine chorionic gonadotrophin (eCG) on corpus luteum development, circulating progesterone concentrations and embryo development in cattle

2016 ◽  
Vol 28 (3) ◽  
pp. 269 ◽  
Author(s):  
L. O'Hara ◽  
N. Forde ◽  
P. Duffy ◽  
F. Randi ◽  
A. K. Kelly ◽  
...  
Keyword(s):  
Corpus Luteum ◽  
Embryo Quality ◽  
Single Injection ◽  
Chorionic Gonadotrophin ◽  
Serum Progesterone ◽  
Conceptus Development ◽  
Luteal Tissue ◽  
Exogenous Progesterone ◽  
Intravaginal Device

The aim was to examine the effect of a single intramuscular (i.m.) injection of equine chorionic gonadotrophin (eCG) on Day 3 after oestrus on corpus luteum (CL) development, circulating progesterone and conceptus development in cross-bred beef heifers. In Experiment 1, heifers received: (1) saline, or a single i.m. injection of eCG on Day 3 at (2) 250 IU (3) 500 IU (4) 750 IU or (5) 1000 IU. Administration of eCG resulted in increased luteal tissue area and progesterone and oestradiol concentrations compared with controls. In Experiment 2, heifers received (1) a progesterone-releasing intravaginal device (PRID Delta) from Day 3 to 5 or (2) a PRID Delta from Day 3 to 5 plus a single injection of 750 IU eCG on Day 3. In vitro-produced blastocysts (n = 10 per recipient) were transferred on Day 7 and heifers were slaughtered on Day 14 to assess conceptus development. Administration of eCG reduced the number of short cycles (6.3% vs 31.3%) and increased mean luteal tissue weight (P = 0.02). Insertion of a PRID Delta on Day 3 resulted in an elevation (P < 0.05) in serum progesterone until removal on Day 5. Administration of eCG at the time of PRID Delta insertion resulted in higher progesterone levels (P < 0.05) from Day 10 onwards. Conceptus dimensions were not affected. In conclusion, a single injection of eCG on Day 3 increased CL size and progesterone concentrations and, when given in conjunction with a progesterone-releasing device, appeared to reduce the number of short cycles, presumably due to its luteotrophic nature. The implications of the elevated oestradiol concentrations for embryo quality require further study.

179 CORPUS LUTEUM DEVELOPMENT AFTER FOLLICLE ASPIRATION IS RELATED TO CHARACTERISTICS OF THE ASPIRATED FOLLICLE IN DAIRY COWS

2013 ◽  
Vol 25 (1) ◽  
pp. 238
Author(s):  
A. Vernunft ◽  
J. M. Weitzel ◽  
T. Viergutz
Keyword(s):  
Corpus Luteum ◽  
Cross Section ◽  
Quality Parameter ◽  
Preovulatory Follicle ◽  
Dominant Follicle ◽  
Cross Section Area ◽  
Section Area ◽  
Luteal Tissue ◽  
The Cross ◽  
Follicle Aspiration

The aim of this study was to investigate whether morphology or function of a corpus luteum (CL), which developed after an aspiration of a preovulatory follicle, is related to follicular characteristics such as size or steroid content. If so, CL morphology or function could be used as a retrospective quality parameter for the aspirated follicle or the follicular characteristics as a prospective parameter for the quality of the developing CL. Therefore, 44 aspiration sessions were performed using 18 cows between 26 and 121 days after parturition during the first lactation. Heat was induced in mid-dioestrus with Cloprostenol. A GnRH analogon (Depherelin) were administrated 54 h later. The dominant follicle was aspirated 21 h after administration of the GnRH analogue. The diameter of the dominant follicle at aspiration and the cross-section area of the resulting luteal tissue 14 days later were measured by ultrasound. Concentrations of progesterone (P4) and 17-β-oestradiol (E2) in blood and follicular fluid (FF) were determined by H3-RIA. A CL development occurred in 82% of aspiration sessions after aspirating the dominant follicles. The interval of time between parturition and follicle aspiration did not affect variables investigated. As expected, cross-section area of the luteal tissue was positively correlated with plasma P4 concentration on Day 14 after follicle aspiration (r = 0.54; P < 0.01). The diameter of the aspirated follicle was positively correlated with the plasma P4 concentration on Day 14 after follicle aspiration (r = 0.52; P = 0.02), but the diameter was not correlated with the cross-section. Comparing the FF of follicles that originated a CL after aspiration with follicles that did not, both types had comparable P4 concentrations (578 ± 79 ng mL–1 v. 398 ± 84 ng mL–1; P = 0.2), but the former type presented higher E2 concentrations (206 ± 23 ng mL–1 v. 64 ± 29 ng mL–1, P < 0.01) compared with the latter. The P4 concentrations in FF of follicles that originated a CL after aspiration were positively related to cross-section area of the CL (r = 0.48; P = 0.04), but neither P4 nor E2 concentrations in the FF of preovulatory follicles could be used as a predictor for the plasma P4 concentration at day 14. In conclusion, CL development after follicle aspiration can be used as a retrospective quality parameter of aspirated dominant follicles. Preovulatory follicle diameter as well as cross-section area of the luteal tissue could be used prospectively to identify cows with high plasma P4 levels, and this may help to identify suitable recipients for embryo transfer. This study was supported by the German Research Foundation (DFG WE 2458/7-2).

109 EFFECT OF SHORT TERM PROGESTERONE SUPPLEMENTATION ON CIRCULATING PROGESTERONE CONCENTRATION, CORPUS LUTEUM SIZE, AND EARLY EMBRYO DEVELOPMENT IN CATTLE

2013 ◽  
Vol 25 (1) ◽  
pp. 202
Author(s):  
L. O'Hara ◽  
N. Forde ◽  
D. Rizos ◽  
V. Maillo ◽  
A. D. Ealy ◽  
...  
Keyword(s):  
Corpus Luteum ◽  
Early Embryo ◽  
Negative Effects ◽  
Short Term ◽  
Concentration Data ◽  
Interferon Tau ◽  
Fluid Medium ◽  
Conceptus Development ◽  
Oviduct Fluid

The aim of this study was to investigate the effect of short term progesterone (P4) supplementation on circulating P4 concentrations, corpus luteum (CL) size, and conceptus development in cattle. The oestrous cycles of crossbred beef heifers were synchronised using a 7-day PRID® Delta (1.55 g P4) treatment with administration of a PGF2α analog (Enzaprost®) the day before PRID® Delta removal. Only those recorded in standing oestrus (Day 0) were used. In Experiment 1, heifers were randomly assigned to 1 of 5 groups: (1) control: no treatment, (2) placebo: insertion of a blank device (no P4) from Day 3 to 7, (3) insertion of a PRID® Delta from Day 3 to 7, (4) insertion of a PRID® Delta from Day 3 to 5, or (v5) insertion of a PRID® Delta from Day 5 to 7. In vitro produced blastocysts were transferred to each heifer on Day 7 (10 blastocysts per heifer) and conceptuses were recovered at slaughter on Day 14. In Experiment 2 heifers were artificially inseminated at oestrus and randomly assigned to 1 of 3 treatment groups (1) placebo, (2) PRID® Delta from Day 3 to 5, or (3) PRID® Delta from Day 3 to 7. All heifers were slaughtered on Day 16, and recovered conceptuses were incubated in synthetic oviduct fluid medium for 24 h; spent media and uterine flushes were analysed for interferon-tau (IFNT). In both experiments, daily blood samples were taken to measure serum P4 concentration. Data were analysed using the PROC MIXED procedure of SAS (SAS Institute Inc., Cary, NC, USA). Insertion of a PRID® Delta resulted in an increase (P < 0.05) in serum P4, which declined following removal. In Experiment 1, serum P4 concentration was significantly lower from Day 9 to 14 (P < 0.05) and Day 14 CL weight was lower in the PRID® Delta Day 3 to 7 group than the placebo or control groups. P4 supplementation from Day 3 to 5 (17.0 ± 1.4 mm) or Day 3 to 7 (11.3 ± 2.3 mm) increased conceptus length compared to the placebo (2.1 ± 1.8 mm). In Experiment 2, serum P4 was significantly lower in the two supplemented groups following PRID® Delta removal compared with the placebo (P < 0.05) and was associated with a lower CL weight in the Day 3 to 7 group. Supplementation from Day 3 to 5 (94.0 ± 18.8 mm) or Day 3 to 7 (143.6 ± 20.6 mm) increased conceptus length on Day 16 compared to the placebo (50.3 ± 17.4 mm). Conceptus length was strongly correlated with the concentration of IFNT in the uterine flush (r = 0.58; P = 0.011) and spent culture medium (r = 0.68; P < 0.002). These findings highlight the somewhat paradoxical effects of P4 supplementation when given in the early metoestrus period in terms of its positive effect on conceptus development and its potentially negative effects on CL lifespan. Supported by CEVA Sante Animale and Science Foundation Ireland (07/SRC/B1156).

4 Relationship Between Ovarian Vascularity, Cumulus–Oocyte Morphology and Luteal Development in Four-Month-Old Calves After FSH Stimulation

2018 ◽  
Vol 30 (1) ◽  
pp. 141
Author(s):  
S. L. Caunce ◽  
A. R. T. Krause ◽  
F. C. F. Dias ◽  
G. P. Adams ◽  
J. Singh
Keyword(s):  
Blood Flow ◽  
Doppler Ultrasound ◽  
3D Analysis ◽  
Adult Cattle ◽  
Plasma Progesterone ◽  
Tissue Volume ◽  
Follicular Aspiration ◽  
Oocyte Collection ◽  
Luteal Tissue ◽  
Follicle Aspiration

The objectives of this study were to determine the effect of LH on the blood flow to the ovaries of 4-month-old calves after 2 FSH stimulation protocols, and to examine the relationship between ovarian vascularity after superstimulation to the morphology of the cumulus–oocyte complexes (COC) and luteal function. We hypothesise that ovarian vascularity (detected by 3-dimensional (3D) analysis of Doppler ultrasound cineloops) will increase in response to LH, and the magnitude of change in vascularity would be predictive of (1) a greater proportion of expanded COC, (2) greater development of luteal tissue volume and vascularity at 3 and 7 days after follicle aspiration, and (3) higher levels of plasma progesterone. Ovarian superstimulation was initiated at the beginning of an induced follicular wave in 4-month-old beef calves (n = 16), and beef cattle >16 months of age (control group, adults; n = 8) using either a traditional 4-day or an extended 7-day FSH protocol (n = 8 calves and n = 4 controls per group). Power Doppler ultrasound cineloops were recorded immediately before (i.e. 12 h after the last FSH treatment) and 24 h after LH treatment (before ultrasound-guided follicular aspiration for oocyte collection) to assess ovarian vascularity, and 3 and 7 days after follicular aspiration to assess luteal tissue volume and vascularity. Video segments were analysed in Fiji and Imaris software to obtain the 3D ovarian vascularity index (ratio of blood flow volume to tissue volume). The ovarian vascularity index tended to increase >1.7-fold in response to exogenous LH in both prepubertal calves (pre-LH 1.5 ± 0.4% v. post-LH 2.6 ± 0.7%; P = 0.08) and adult cattle (pre-LH 2.2 ± 0.6% v. post-LH 4.7 ± 0.9%; P = 0.07). Calves with a recovery of >75% of expanded COC had a higher ovarian vascularity index (10.7 ± 2.6% v. 4.8 ± 1.6%; P = 0.06) and luteal vascularity index (15.7 ± 4.5% v. 5.7 ± 2.1%; P < 0.05) 7 days after aspiration than those with <75% expanded COC. Calves in the 7-day FSH protocol had >10-fold higher concentration of plasma progesterone on Day 3 (12.7 ± 7.3 ng mL−1 v. 1.2 ± 0.4 ng mL−1; P < 0.05) and Day 5 (50.6 ± 28.0 ng mL−1 v. 4.5 ± 1.0 ng mL−1; P < 0.05), and ~2-fold higher luteal vascularity index at 7 days after follicle aspiration (13.7 ± 4.6% v. 7.7 ± 2.8%; P < 0.05) than calves in the 4-day FSH protocol, whereas no difference (P > 0.05) was found in control (adult) animals. In conclusion, there was an increase in ovarian vascularity resulting from LH treatment in prepubertal calves and adult cattle. A greater proportion of expansion of COC at 24 h after LH treatment (an indicator of follicular maturation) was related to higher ovarian and luteal vascularity on Day 7 after collection in prepubertal calves, but not in adults. Luteal vascularity on Day 3 was reflective of plasma progesterone concentration, and prepubertal calves in the 7-day FSH protocol had greater plasma progesterone than calves in the 4-day FSH protocol. The use of FSH in calves allows a greater number of follicles for oocyte collection as it does in adult cattle. Research was supported by an NSERC grant.

Effects of human chorionic gonadotrophin administration on Day 5 after oestrus on corpus luteum characteristics, circulating progesterone and conceptus elongation in cattle

2012 ◽  
Vol 24 (3) ◽  
pp. 472 ◽  
Author(s):  
D. Rizos ◽  
S. Scully ◽  
A. K. Kelly ◽  
A. D. Ealy ◽  
R. Moros ◽  
...  
Keyword(s):  
Corpus Luteum ◽  
Intramuscular Injection ◽  
Chorionic Gonadotrophin ◽  
Human Chorionic Gonadotrophin ◽  
Control Group ◽  
Strong Positive Correlation ◽  
Serum Concentrations ◽  
Luteal Tissue ◽  
Highly Correlated

The aim of the present study was to test the hypothesis that elevated concentrations of progesterone (P4) resulting from the induction of an accessory corpus luteum (CL) by human chorionic gonadotrophin (hCG) administration on Day 5 after oestrus would lead to advanced conceptus elongation on Day 14 following embryo transfer on Day 7. The oestrous cycles of cross-bred beef heifers were synchronised and animals were randomly assigned to receive either of two treatments: (1) intramuscular injection of 3000 IU hCG on Day 5 after oestrus (n = 14); or (2) intramuscular injection of saline on Day 5 after oestrus (n = 13). Ovaries were scanned daily by transrectal ultrasonography to assess CL development. Serum concentrations of P4 were determined from daily blood samples collected from the jugular vein. In vitro-produced bovine blastocysts were transferred to synchronised recipients on Day 7 after oestrus (n = 15 blastocysts per recipient). Heifers were killed on Day 14 after oestrus and the uterus was flushed to recover the embryos. Injection of hCG on Day 5 induced ovulation of the dominant follicle in all treated heifers and increased the total area of luteal tissue on the ovary, which was associated with a significant increase (P < 0.001) in serum concentrations of P4 from Day 7 to Day 14. Positive associations were detected between circulating P4 with CL area (within-day correlations ranging from r = 0.45 to r = 0.67) and total area of luteal tissue (within-day correlations ranging from r = 0.65 to r = 0.86) Administration of hCG did not affect the proportion of Day 14 conceptuses recovered. However, compared with the control group, hCG-treated heifers had increased conceptus length (3.91 ± 1.23 vs 5.57 ± 1.02 mm, respectively; P = 0.06), width (1.00 ± 0.06 vs 1.45 ± 0.05 mm, respectively; P = 0.002) and area (5.71 ± 0.97 vs 8.31 ± 0.83, respectively; P = 0.02). Although numerically greater, mean interferon-τ (IFNT) production in vitro did not differ significantly (P = 0.54) between embryos recovered from hCG-treated and control heifers. In contrast, there was a strong positive correlation between individual embryo length (r = 0.76; P < 0.001) and individual embryo area (r = 0.72; P < 0.001) and IFNT production. In conclusion, administration of hCG on Day 5 after oestrus resulted in the formation of an accessory CL and hypertrophy of the original CL, the result of which was an increase in P4 concentrations from Day 7 onwards. These elevated P4 concentrations were associated with an increased conceptus area. Furthermore, conceptus size was highly correlated with IFNT secretion in vitro.

Role of progesterone in embryo development in cattle

2016 ◽  
Vol 28 (2) ◽  
pp. 66 ◽  
Author(s):  
Pat Lonergan ◽  
Niamh Forde ◽  
Thomas Spencer
Keyword(s):  
Corpus Luteum ◽  
Embryo Development ◽  
Early Pregnancy ◽  
Pregnancy Rates ◽  
In Vitro Experiments ◽  
Conceptus Development

Progesterone (P4) from the corpus luteum is critical for the establishment and maintenance of pregnancy and plays a major role in regulating endometrial secretions essential for stimulating and mediating changes in conceptus growth and differentiation throughout early pregnancy in ruminants. Numerous studies have demonstrated an association between elevated systemic P4 and acceleration in conceptus elongation. A combination of in vivo and in vitro experiments found that the effects of P4 on conceptus elongation are indirect and mediated through P4-induced effects in the endometrium. Despite effects on elongation, data on the effects of post-insemination supplementation with P4 on pregnancy rates are conflicting. This review highlights the effects of P4 on conceptus development and examines strategies that have been undertaken to manipulate P4 concentrations to increase fertility.

Prolactin stimulates steroidogenesis by human luteal tissue in vitro

1984 ◽  
Vol 103 (1) ◽  
pp. 107-110 ◽  
Author(s):  
M. G. Hunter
Keyword(s):  
Corpus Luteum ◽  
Luteal Phase ◽  
Chorionic Gonadotrophin ◽  
Human Chorionic Gonadotrophin ◽  
Corpora Lutea ◽  
Progesterone Production ◽  
Luteal Tissue ◽  
Oestradiol Production ◽  
Human Corpus Luteum

ABSTRACT Human luteal tissue recovered from varying stages of the luteal phase was minced and incubated for 3 h and the effect of human chorionic gonadotrophin (hCG), prolactin and hCG + prolactin on progesterone and oestradiol production measured. While hCG generally enhanced both progesterone and oestradiol synthesis, prolactin alone at either 20 or 200 μg/l had no significant effect on steroidogenesis. When prolactin was added along with hCG in four of six corpora lutea, however, progesterone production significantly increased and in three of six corpora lutea oestradiol production was increased above that induced by hCG alone. It is concluded that prolactin may play some role in the control of steroidogenesis by the human corpus luteum. J. Endocr. (1984) 103, 107–110

scholarly journals Corpus luteum development and its morphology after aspiration of a preovulatory follicle is related to size and steroid content of the follicle in dairy cows

2013 ◽  
Vol 58 (No. 4) ◽  
pp. 221-229 ◽  
Author(s):  
A. Vernunft ◽  
JM Weitzel ◽  
T. Viergutz
Keyword(s):  
Dairy Cows ◽  
Corpus Luteum ◽  
Cross Section ◽  
Preovulatory Follicle ◽  
Dominant Follicle ◽  
Cross Section Area ◽  
Section Area ◽  
Preovulatory Follicles ◽  
Luteal Tissue ◽  
Follicle Aspiration

Secretion of adequate levels of progesterone from a proper corpus luteum (CL), which develops out of the cells of a healthy preovulatory follicle, is a key-factor for establishment of a pregnancy. The aim of this study was to investigate the relationship between morphological and secretory characteristics of preovulatory follicles and their corresponding corpus luteum with regard to the post-partum period in high-yielding dairy cows. Therefore, ultrasound-guided aspirations of preovulatory follicles were performed repeatedly, using 20 first lactating cows between 26 and 121 days after parturition. Heat was induced with a PGF analogon followed by administration of a GnRH analogon. The dominant follicle was aspirated 21 h after administration of the GnRH analogon. The diameters of the follicles were estimated at aspiration and the morphology of the resulting luteal tissue was examined on day 14 after follicle aspiration using ultrasonographic examinations. Concentrations of progesterone (P<sub>4</sub>) and 17-beta-oestradiol (E<sub>2</sub>) were determined in the follicular fluids (FF) and P<sub>4</sub> concentration was estimated at the time of CL examination in plasma. A CL development occurred in 82% after dominant follicle aspiration. The interval of time between parturition and follicle aspiration did not affect the investigated variables. The diameter of the aspirated preovulatory follicle was positively correlated to the cross-section area of the developed luteal tissue (R = 0.60; P &lt; 0.01) as well as to the plasma P<sub>4</sub> concentration on day 14 after follicle aspiration (R = 0.47; P&nbsp;&lt; 0.05). Also, E<sub>2</sub> concentrations in FF were positively correlated to cross-section area of the luteal tissue (R = 0.54; P &lt; 0.05). Comparing the FF of the follicles that gave rise to a CL after aspiration to follicles that did not, both types had comparable P<sub>4</sub>, but the former type harboured higher E<sub>2</sub> concentrations. In conclusion, preovulatory follicle diameter as well as steroid concentrations in the follicular fluid could be used prospectively to identify cows which will have well-developed CLs and high plasma P<sub>4</sub> levels later. On the other hand, CL development after follicle aspiration can be used as a retrospective quality parameter of dominant follicles. These results will help to identify suitable animals for breeding or recipients for embryo transfer.&nbsp;&nbsp;&nbsp; &nbsp;

110 EFFECT OF HUMAN CHORIONIC GONADOTROPIN (hCG) ADMINISTRATION ON DAYS 1, 2, 3, OR 4 POST-OESTRUS ON CORPUS LUTEUM DEVELOPMENT AND CIRCULATING PROGESTERONE CONCENTRATIONS IN BEEF HEIFERS

2013 ◽  
Vol 25 (1) ◽  
pp. 202 ◽  
Author(s):  
V. Maillo ◽  
P. Duffy ◽  
L. O'Hara ◽  
C. de Frutos ◽  
A. K. Kelly ◽  
...  
Keyword(s):  
Corpus Luteum ◽  
Chorionic Gonadotropin ◽  
Human Chorionic Gonadotropin ◽  
Dominant Follicle ◽  
Uterine Receptivity ◽  
Beef Heifers ◽  
Interferon Tau ◽  
Downstream Effects ◽  
Luteal Tissue ◽  
Reproductive Events

The steroid hormone progesterone (P4) plays a key role in the reproductive events associated with the establishment and maintenance of pregnancy. Elevated concentrations of circulating P4 in the immediate post-conception period have been associated with advanced conceptus elongation, increased interferon-tau production, and greater pregnancy rates in cattle. Several strategies have been employed to supplement the endogenous P4 supplied by the corpus luteum (CL). One such strategy is the administration of human chorionic gonadotropin (hCG) during the early luteal phase (typically Day 5) that induces ovulation of the first wave dominant follicle and formation of a functional accessory CL, in turn leading to increased circulating concentrations of P4. In addition to this effect, hCG also stimulates hypertrophy of the original CL, leading to a significant deviation in P4 concentrations 2 days after administration. The aim of this study was to examine whether administration of hCG earlier during the metoestrus period would lead to an earlier rise in P4 by stimulation of the developing endogenous CL. The oestrous cycles of cross-bred beef heifers (n = 50) were synchronised and those recorded in standing oestrus (Day 0) were assigned randomly to one of 5 treatments and administered a single IM injection of saline on Day 1 after oestrus (Control) or 3000 IU hCG on Day 1, 2, 3, or 4 after oestrus. Daily blood samples were collected from Day 0 to 14 by coccygeal venipuncture to measure serum P4 concentration. The dimensions of the original CL and induced CL, when present, were measured by daily ultrasound scanning beginning on Day 3 after oestrus until Day 14. Data were analysed using the PROC MIXED procedure of SAS (SAS Institute Inc., Cary, NC, USA). In terms of effects on the CL, administration of hCG on Day 1 had no effect on CL area. Administration on Day 2 increased CL area from Day 6 to 12 (P ≤ 0.05). hCG on Day 3 increased CL area from Day 9 to 11, while administration on Day 4 increased CL size on Day 9 and 10 (P ≤ 0.05). Administration of hCG on Day 4 induced the formation of an accessory CL in 89% of heifers, resulting in a significant increase in total luteal tissue area on the ovaries compared to all other groups. Consistent with the effects on the CL, hCG on Day 1 did not affect P4 concentrations. Administration on Day 2 significantly increased P4 compared to the control from Day 6 to 11 (P ≤ 0.05). Administration on Day 3 resulted in a nonsignificant increase in P4, while hCG on Day 4 increased P4 from Day 8 to 13 compared to the control (P ≤ 0.05). In conclusion, administration of hCG as early as Day 2 post oestrus results in increased P4 in circulation from Day 6 which should have beneficial downstream effects in terms of uterine receptivity and conceptus elongation. Funded by Science Foundation Ireland (07/SRC/B1156) and the Spanish Ministry of Science and Innovation AGL2009-11810.

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