Temporal relationships of the LH surge and ovulation to echotexture and power Doppler signals of blood flow in the wall of the preovulatory follicle in heifers

2010 ◽  
Vol 22 (7) ◽  
pp. 1110 ◽  
Author(s):  
M. A. R. Siddiqui ◽  
J. C. Ferreira ◽  
E. L. Gastal ◽  
M. A. Beg ◽  
D. A. Cooper ◽  
...  
Keyword(s):  
Blood Flow ◽  
Power Doppler ◽  
Initial Increase ◽  
Preovulatory Follicle ◽  
Lh Surge ◽  
Follicle Diameter ◽  
Temporal Relationships ◽  
Preovulatory Follicles ◽  
Doppler Signals ◽  
Gonadotrophin Releasing Hormone

Changes in echotexture and blood flow in the wall of preovulatory follicles in heifers were studied in relation to the LH surge and ovulation in gonadotrophin-releasing hormone-induced (n = 7; Experiment 1) and spontaneous (n = 8; Experiment 2) ovulators. Ultrasonographic examinations and blood sampling were performed either every hour (Experiment 1) or every 6 h (Experiment 2). The interval from LH peak to ovulation in induced and spontaneous ovulators was 27.1 ± 0.3 and 34.5 ± 1.5 h, respectively. Follicle diameter did not increase between the LH peak and ovulation. In the induced ovulators, serration of the stratum granulosum was detected in one (14%), two (29%), three (43%) and four (57%) heifers at 4, 3, 2 and 1 h before ovulation, respectively. An initial increase in blood flow (P < 0.001) encompassed the LH peak in both experiments. In the induced ovulators, blood flow increased (P < 0.02) to maximum 3 h after the LH peak, maintained a plateau for 5 h, decreased (P < 0.05) between 9 and 14 h, increased (P < 0.05) again between 19 and 21 h and then decreased (P < 0.01) between 25 and 26 h (1 h before ovulation). The biphasic increase and decrease in blood flow and serration of the granulosum in the wall of the preovulatory follicle in cattle are novel findings.

124 RELATIONSHIPS BETWEEN PREOVULATORY FOLLICLE AND CORPUS LUTEUM BLOOD FLOW IN MARES

2012 ◽  
Vol 24 (1) ◽  
pp. 174
Author(s):  
A. Wischral ◽  
K. T. Haag ◽  
G. R. Fonseca ◽  
M. O. Gastal ◽  
S. S. King ◽  
...  
Keyword(s):  
Blood Flow ◽  
Doppler Ultrasonography ◽  
New Technologies ◽  
Power Doppler ◽  
Corpora Lutea ◽  
Power Doppler Ultrasonography ◽  
Preovulatory Follicle ◽  
Vascular Perfusion ◽  
Follicle Diameter ◽  
Student’S T

Colour- and power-Doppler ultrasonography have recently been used as potential new technologies to assess the degree of vascular perfusion of the ovary and follicles for research and clinical studies of ovarian and follicle hemodynamics and to predict fertility in horses, cattle and humans. In the present study, the following hypotheses were tested: (1) preovulatory follicle (POF) diameter (≥30 mm), but not blood flow, is repeatable between cycles within the same mare; (2) POF diameter and blood flow are good indicators of follicle status; (3) double POF have similar blood flow; and (4) highly vascularized POF produce corpora lutea (CL) with greater blood flow. Non-lactating mares (n = 13; 5 to 21 years old) of mixed breeds were used from March to May in the Northern Hemisphere. Follicle diameter and vascularity of the follicle wall before the first and second ovulations of the season and vascularity of the first CL were measured daily using transrectal colour-Doppler ultrasonography. The vascularity of the follicle wall and CL was based on the display of the blood-flow signals visualised in a slow, continuous-motion evaluation. Statistical analyses were performed by the SAS MIXED procedure, ANOVA and Student's t-tests and Spearman's correlation. A total of 26 periovulatory periods were evaluated. Unexpectedly, there were 84.6% (11/13) and 61.5% (8/13) double dominant POF and 30.8% (4/13) and 46.2% (6/13) double ovulations in the first and second periovulatory periods, respectively. The POF diameters were highly correlated (r = 0.68; P < 0.0001) between the first and second periovulatory periods. The diameter of the POF 5 days before the first ovulation was larger (P < 0.004) than before the second ovulation of the year. However, the POF vascularity did not differ between those periods. For 4 days before ovulation (Day 0), the diameter and blood flow of the POF were greater (P < 0.05) than for those follicles that underwent atresia in single- and double-ovulatory mares. The POF diameter and blood flow were positively correlated in ovulatory (r = 0.51; P < 0.0001) and in atretic (r = 0.32; P < 0.02) follicles. In double-ovulatory mares, POF diameter and blood flow increased (P < 0.0006) for 5 days before ovulation, with no difference between the 2 follicles in the same cycle for each parameter. The POF blood flow was positively correlated (r = 0.32; P < 0.0009) with CL vascularity during the first periovulatory period (Day –7 to +6) of the season. Furthermore, a positive correlation (r = 0.58; P < 0.01) was observed between the maximum vascularity of the POF and its subsequent CL. In conclusion, although preliminary, our results demonstrated that (a) POF vascularity is not repeatable within individuals; (b) potential atretic POF have low blood flow; (c) double POF have similar vascularity; and (d) greater blood flow to the POF is associated with higher CL vascularity.

scholarly journals Local changes in blood flow within the preovulatory follicle wall and early corpus luteum in cows

Reproduction ◽  
2003 ◽  
pp. 759-767 ◽  
Author(s):  
TJ Acosta ◽  
KG Hayashi ◽  
M Ohtani ◽  
A Miyamoto
Keyword(s):  
Blood Flow ◽  
Corpus Luteum ◽  
Plasma Concentrations ◽  
Maximum Velocity ◽  
Initial Increase ◽  
Preovulatory Follicle ◽  
Lh Surge ◽  
Functional Changes ◽  
Induced Ovulation ◽  
Doppler Image

Haemodynamic changes are involved in the cyclic remodelling of ovarian tissue that occurs during final follicular growth, ovulation and new corpus luteum development. The aim of this study was to characterize the real-time changes in the blood flow within the follicle wall associated with the LH surge, ovulation and corpus luteum development in cows. Normally cyclic cows with a spontaneous ovulation (n = 5) or a GnRH-induced ovulation (n = 5) were examined by transrectal colour and pulsed Doppler ultrasonography to determine the area and the time-averaged maximum velocity (TAMXV) of the blood flow within the preovulatory follicle wall and the early corpus luteum. Ultrasonographic examinations began 48 h after a luteolytic injection of PGF(2alpha) analogue was given at the mid-luteal phase of the oestrous cycle. Cows with spontaneous ovulation were scanned at 6 h intervals until ovulation occurred. Cows with GnRH-induced ovulation were scanned just before GnRH injection (0 h), thereafter at 0.5, 1, 2, 6, 12, 24 h and at 24 h intervals up to day 5. Blood samples were collected at the same time points for oestradiol, LH and progesterone determinations. Cows with both spontaneous and GnRH-induced ovulation showed a clear increase in the plasma concentration of LH (LH surge) followed by ovulation 26-34 h later. In the colour Doppler image of the preovulatory follicle, the blood flow before the LH surge was detectable only in a small area in the base of the follicle. An acute increase in the blood flow velocity (TAMXV) was detected at 0.5 h after GnRH injection, synchronously with the initiation of the LH surge. At 12 h after the LH surge, the plasma concentrations of oestradiol decreased to basal concentrations. The TAMXV remained unchanged after the initial increase until ovulation, but decreased on day 2 (12-24 h after ovulation). In the early corpus luteum, the blood flow (area and TAMXV) gradually increased in parallel with the increase in corpus luteum volume and plasma progesterone concentration from day 2 to day 5, indicating active angiogenesis and normal luteal development. Collectively, the complex structural, secretory and functional changes that take place in the ovary before ovulation are closely associated with a local increase in the blood flow within the preovulatory follicle wall. The result of the present study provides the first visual information on vascular and blood flow changes associated with ovulation and early corpus luteum development in cows. This information may be essential for future studies involving pharmacological control of blood flow and alteration of ovarian function.

Defining the gonadotrophin requirement for the selection of a single dominant follicle in cattle

2020 ◽  
Vol 32 (3) ◽  
pp. 322 ◽  
Author(s):  
Jin G. Gong ◽  
Bruce K. Campbell ◽  
Robert Webb
Keyword(s):  
Major Effect ◽  
Follicle Development ◽  
Preovulatory Follicle ◽  
Ultrasound Scanning ◽  
Dominant Follicle ◽  
Initial Exposure ◽  
Preovulatory Follicles ◽  
Gonadotrophin Releasing Hormone ◽  
Follicular Response ◽  
Selection Of

The aim was to define the pattern and physiological concentrations of FSH and LH required for the selection of a single dominant follicle in mono-ovulatory species. A series of five experiments was carried out using gonadotrophin-releasing hormone agonist-induced hypogonadal heifers. Animals were infused with different patterns of either FSH and/or LH followed by an ovulatory dose of human chorionic gonadotrophin. Follicular response was monitored by ultrasound scanning and blood samples were collected to measure concentrations of FSH, LH, oestradiol and progesterone. The main findings were: (1) physiological concentrations of FSH given as a continuous infusion and for an adequate duration, in the presence of basal LH, with or without LH pulses, are capable of inducing a superovulatory response, (2) initial exposure to FSH followed by LH pulses alone stimulate the development of multiple preovulatory follicles, confirming that ovarian follicles are capable of transferring dependence on gonadotrophins from FSH to LH, (3) while LH pulses appear not to have a major effect on the pattern of preovulatory follicle development, adequate LH pulsatile support is required for full oestradiol synthesis and (4) the duration of initial exposure to FSH and the ability to transfer the dependence from FSH to LH are critical for the selection of a single dominant follicle. In conclusion, this experimental series confirms that the duration of initial exposure to FSH and the ability of the selected follicle to transfer its gonadotrophic dependence from FSH to LH are critical for the selection of a single dominant follicle in cattle.

Characterizing the neuroendocrine and ovarian defects of androgen receptor-knockout female mice

2013 ◽  
Vol 305 (6) ◽  
pp. E717-E726 ◽  
Author(s):  
Xiaobing B. Cheng ◽  
Mark Jimenez ◽  
Reena Desai ◽  
Linda J. Middleton ◽  
Shai R. Joseph ◽  
...  
Keyword(s):  
Androgen Receptor ◽  
Negative Feedback ◽  
Positive Feedback ◽  
Growth Patterns ◽  
Corpora Lutea ◽  
Preovulatory Follicle ◽  
Lh Surge ◽  
Antral Follicles ◽  
Female Mice ◽  
Follicle Diameter

Homozygous androgen receptor (AR)-knockout (ARKO) female mice are subfertile due to both intra- and extraovarian (neuroendocrine) defects as defined by ovary transplantation. Using ARKO mice, this study set out to reveal the precise AR-regulated pathways required for optimal androgen-regulated ovulation and fertility. ARKO females exhibit deficient neuroendocrine negative feedback, with a reduced serum luteinizing hormone (LH) response to ovariectomy (OVX) ( P < 0.01). Positive feedback is also altered as intact ARKO females, at late proestrus, exhibit an often mistimed endogenous ovulatory LH surge. Furthermore, at late proestrus, intact ARKO females display diminished preovulatory serum estradiol (E2; P < 0.01) and LH ( P < 0.05) surge levels and reduced Kiss1 mRNA expression in the anteroventral periventricular nucleus ( P < 0.01) compared with controls. However, this reduced ovulatory LH response in intact ARKO females can be rescued by OVX and E2 priming or treatment with endogenous GnRH. These findings reveal that AR regulates the negative feedback response to E2, E2-positive feedback is compromised in ARKO mice, and AR-regulated negative and positive steroidal feedback pathways impact on intrahypothalamic control of the kisspeptin/GnRH/LH cascade. In addition, intraovarian AR-regulated pathways controlling antral to preovulatory follicle dynamics are disrupted because adult ARKO ovaries collected at proestrus have small antral follicles with reduced oocyte/follicle diameter ratios ( P < 0.01) and increased proportions of unhealthy large antral follicles ( P < 0.05) compared with controls. As a consequence of aberrant follicular growth patterns, proestrus ARKO ovaries also exhibit fewer preovulatory follicle ( P < 0.05) and corpora lutea numbers ( P < 0.01). However, embryo development to the blastocyst stage is unchanged in ARKO females, and hence, the subfertility is a consequence of reduced ovulations and not altered embryo quality. These findings reveal that the AR has a functional role in neuroendocrine regulation and timing of the ovulatory LH surge as well as antral/preovulatory follicle development.

219 FOLLICLE AND HORMONE DYNAMICS IN SINGLE- v. DOUBLE-OVULATING HEIFERS

2010 ◽  
Vol 22 (1) ◽  
pp. 267
Author(s):  
M. P. Palhao ◽  
M. A. Beg ◽  
M. T. Rodrigues ◽  
R. R. Araújo ◽  
J. H. M. Viana ◽  
...  
Keyword(s):  
Present Experiment ◽  
Group Effect ◽  
Preovulatory Follicle ◽  
Follicle Growth ◽  
Blood Samples ◽  
Lh Surge ◽  
Follicular Wave ◽  
Preovulatory Follicles ◽  
Main Effect ◽  
Plasma Hormone

The present experiment used the Day 4 ablation model for increasing the incidence of double ovulations in heifers. The objective was to compare follicle growth and plasma hormone concentrations associated with single v. double ovulations. Follicles ≥5 mm were ablated at 4 days post-ovulation to induce a prominent FSH surge and a new follicular wave, and 2 injections of PGF2 (12 h apart) were given 2 days later (Day 6) to favor ovulation. Beginning on Day 5, the 3 largest follicles of the induced wave were scanned twice a day until 36 h after the next ovulation. Blood samples were taken at 6-h intervals starting when the largest follicle reached ≥8.0 mm (expected deviation at 8.5 mm; Ginther et al. 1996) and continued until 36 h after the next ovulation. Concentrations of LH and FSH were measured by validated RIA for cattle (LH measured by Ginther et al. 1999; FSH measured by Adams et al. 1992) and concentrations of oestradiol measured by a commercially available RIA kit (Siddiqui et al. 2009). From a total of 31 heifers, 16 (52%) or 15 (48%) developed a single or more than 1 dominant (≥ 10 mm) follicle in the follicular wave after ablation, respectively. For heifers with 2 dominant follicles, the second-largest follicle ovulated in 9 (60%) heifers and the overall double ovulation rate was 29% (9/31). Follicle diameters and plasma hormone concentrations were compared between single ovulators (n = 12) and double ovulators (n = 8). Diameter of the preovulatory follicles did not increase between the LH peak and ovulation in either the single or double ovulations. In double ovulators, the interval from follicle deviation to the peak of the preovulatory LH surge was shorter (1.9 ± 0.2 days v. 2.5 ± 0.2 days; P < 0.02) and the diameter of the largest preovulatory follicle was smaller (12.2 ± 0.5 mm v. 13.3 ± 0.3 mm; P < 0.02) than in single ovulators, respectively. The LH concentrations of the preovulatory surge did not differ between single and double ovulators for 24 h on each side of the peak (main effect of hour only; P < 0.0001). When data were normalized to the LH peak, the peak of the preovulatory FSH and estradiol surges occurred in synchrony with the peak of LH surge for both groups. A group effect (P < 0.0001) for FSH resulted from a lower concentration averaged over hours in double ovulators. Estradiol showed a group by hour interaction (P < 0.008), reflecting greater concentrations in the double ovulators before and at peak. In conclusion, an increased Supported by the Eutheria Foundation, Cross Plains, WI, USA. Submission supported by FAPEMIG.

scholarly journals Effect of eCG on the follicular dynamics and vascularization of crossbred cows with different circulating progesterone concentrations during synchronization of ovulation in an FTAI protocol

2019 ◽  
Vol 39 (5) ◽  
pp. 324-331 ◽  
Author(s):  
Priscila A. Ferraz ◽  
Mariana A.A. Silva ◽  
Bia S.S. Carôso ◽  
Endrigo A.B. Araujo ◽  
Thereza C.B.S.C. Bittencourt ◽  
...  
Keyword(s):  
Power Doppler ◽  
Fixed Time ◽  
High Plasma ◽  
Preovulatory Follicle ◽  
Crossbred Cows ◽  
Follicle Diameter ◽  
Dynamics And Function ◽  
And Function ◽  
Synchronization Protocol ◽  
Follicular Dynamics

ABSTRACT: This study aimed to evaluate the effect of treatment with equine chorionic gonadotrophin (eCG) on the follicular dynamics and function of crossbred cows with different circulating progesterone (P4) concentrations during synchronization of ovulation in a fixed-time artificial insemination (FTAI) protocol. To this end, 30 crossbred cows were submitted to a pre-synchronization protocol to ensure that all of them presented corpus luteum (CL) at the beginning of the protocol, and were evaluated by transrectal ultrasonography (TRUS) to verify the presence of CL. After that, the animals underwent an ovulation synchronization protocol and evaluation of follicular dynamics and vascularization by B-mode and power-Doppler ultrasound (US). High plasma P4 concentrations at the time of ovulation synchronization negatively influenced follicle diameter on day 10 (D10), preovulatory follicle diameter, and preovulatory follicle wall vascularization area (p<0.05). Cows with high P4 concentration at the time of ovulation synchronization that were treated with eCG showed follicle diameter on D10 and preovulatory follicle diameter and wall vascularization area (p>0.05) similar to those of animals with low P4 concentration at the time of ovulation synchronization. Therefore, high P4 concentrations at the time of ovulation synchronization negatively influence follicular diameter and vascularization, and eCG can be used as a strategy to favor better follicular and luteal response in crossbred cows with high P4 concentrations submitted to an FTAI protocol.

182 EFFECT OF OVULATION-INDUCING FACTOR ON DEVELOPMENT AND VASCULAR PERFUSION OF THE OVULATORY FOLLICLE AND CORPUS LUTEUM IN LLAMAS

2013 ◽  
Vol 25 (1) ◽  
pp. 240
Author(s):  
C. Ulloa-Leal ◽  
O. Bogle ◽  
G. P. Adams ◽  
M. Ratto
Keyword(s):  
Blood Flow ◽  
Seminal Plasma ◽  
Research Council ◽  
Power Doppler ◽  
Transrectal Ultrasonography ◽  
Maximum Diameter ◽  
Preovulatory Follicle ◽  
Vascular Perfusion ◽  
Flow Signal ◽  
Blood Flow Signal

The aim of the study was to determine if purified ovulation-inducing factor (OIF) from llama seminal plasma evokes changes in tissue vascular area of the preovulatory follicle and CL. Mature non-lactating, non-pregnant, female llamas (n = 20) were monitored by transrectal ultrasonography using a 7.5-MHz linear-array transducer (MyLab 5, Canadian Veterinary Imaging) to determine ovarian follicular status. Llamas with a growing follicle (for 3 consecutive days) ≥8 mm were assigned randomly to 2 groups (n = 10/group) and given an i.m. dose of (1) 50 µg of gonadorelin acetate or (2) 1 mg of purified OIF from llama seminal plasma. Llamas were examined daily by transrectal ultrasonography using B-mode and power Doppler mode from Day 0 (day of treatment) to Day 16 to detect ovulation and CL development, and to calculate the area of blood-flow signal in the preovulatory follicle at 12 h after treatment and in the CL on Days 2, 4, 6, 8, 10, 12, 14, and 16. Power Doppler images were recorded, edited, and analysed using the ImageJ software (National Institutes of Health, Bethesda, MD, USA). Data were compared between groups by Student t-test, chi-square, and ANOVA for repeated measures. No differences were detected between GnRH and OIF groups, respectively, in the diameter of the preovulatory follicle at the time of treatment (9.7 ± 0.3 v. 9.9 ± 0.4 mm), ovulation rate (10/10 v. 10/10), interval from treatment to ovulation (32.0 ± 0.6 v. 30.4 ± 1.8 h), maximum CL diameter (13.05 ± 0.4 v. 13.5 ± 0.3 mm), or the day on which the CL reached the maximum diameter (8.7 ± 0.3 v. 8.2 ± 0.2). The preovulatory follicle from llamas treated with purified OIF had a greater (P ≤ 0.0001) blood-flow signal area after treatment than that of the GnRH group. Similarly, the luteal tissue of llamas treated with purified OIF had a greater (P ≤ 0.001) blood-flow signal area than that of the GnRH group on Days 4, 6, 12, and 16 after treatment. We conclude that OIF purified from llama seminal plasma increases the vascular perfusion of the preovulatory follicle and the subsequent CL, consistent with the hypothesis that OIF is luteotrophic. Research funded by Chilean National Science and Technology Research Council (Fondecyt Regular 1120518), the Natural Sciences and Engineering Research Council of Canada, and the Alpaca Research Foundation.

176 BLOOD FLOW TO THE CORPUS LUTEUM AND PREOVULATORY FOLLICLE AFTER OVULATION INDUCTION DURING FIRST VERSUS SECOND WAVE IN WATER BUFFALO

2015 ◽  
Vol 27 (1) ◽  
pp. 179
Author(s):  
S. Caunce ◽  
D. Dadarwal ◽  
P. S. Brar ◽  
J. Singh
Keyword(s):  
Blood Flow ◽  
Corpus Luteum ◽  
Prostaglandin F2α ◽  
Preovulatory Follicle ◽  
Dominant Follicle ◽  
Flow Area ◽  
Vascular Area ◽  
Preovulatory Follicles ◽  
Luteal Tissue ◽  
Second Wave

The objective of the study was to compare the blood flow to the corpus luteum (CL) and the preovulatory follicle in dairy buffalo (Bubalus bubalis) when ovulation was induced during the first (low to increasing progesterone levels) versus the second (luteal progesterone levels) follicular wave. We hypothesised that the wall of the first-wave dominant follicle will be less vascular compared with that of the second-wave follicle. The study was conducted during the summer months in Punjab, India. Ovulation was synchronized with prostaglandin F2α (PGF) IM followed by gonadotropin-releasing hormone (GnRH) IM 48 h later (Day 0) and buffaloes were randomised to first wave (FW; n = 6) and second wave (SW; n = 7) groups. FW group was given PGF on Days 6.5 and 7, and GnRH on Day 9.5 followed by AI (14–16 h after GnRH). The SW group was given GnRH on Day 7 (to induce ovulation of first-wave dominant follicle without luteolysis and synchronous emergence of next wave), PGF on Days 13.5 and 14, GnRH on Day 16.5 followed by artificial insemination. Transrectal colour Doppler ultrasonography (MyLab5 Vetwith 7.5 MHz transducer, Esaote S.p.A, Genoa, Italy) was performed daily and 20-s cineloops of each ovary were recorded under standardized gain controls. Images from the cineloops were processed using Fiji (ImageJ, National Institutes of Health, Bethesda, MD, USA) to calculate the area of blood flow (coloured area = vascular area, grey scale area = tissue area, and their ratio) for the preovulatory follicle (on the day before ovulation) and luteal tissue (on the day of PGF injection and 4 days post-ovulation). Data were analysed by t-test from the animals that ovulated one day before (n = 3) or the day of AI (n = 6) and had a functional CL at day 5 post-AI (FW n = 5, SW n = 4). FW follicles ovulated on 8.6 ± 0.3 days from wave emergence compared with SW follicles on 10.0 ± 0.6 days (P < 0.05) but were similar in size (i.e. follicular area on the day before ovulation did not differ between groups; P = 0.5). There was no difference in the blood flow area in the wall of preovulatory follicles (P = 0.4). Vascular area of follicles was strongly correlated with their diameter (r = 0.87). Follicles >13.5 mm in diameter had more blood flow in their wall than smaller follicles (P < 0.01). FW had a tendency (P = 0.07) for smaller luteal area on the day of PGF treatment (FW = 171 ± 24 mm2; SW = 332 ± 81 mm2) and tended (P = 0.06) to have less vascular area in the CL compared to SW group (FW = 30 ± 6 mm2; SW = 67 ± 17 mm2). There was no difference (P = 0.5) between the groups for vascular to CL area ratio. The area of luteal tissue and blood flow to the CL at Day 4 post-ovulation did not differ between the groups (P = 0.4). The diameter of the preovulatory follicle (11.6–15.7 mm) was not correlated with the cross-sectional area of developing CL at Day 4 post-ovulation (r = 0.09). In conclusion, vascularity to preovulatory follicles originating from the first wave v. second wave did not differ and preovulatory follicles ≥13.5 mm were more vascular than smaller follicles. Research was funded by NSERC; the first author was funded by scholarships from WCVM and GADVASU.

117 INDUCTION OF OVULATION WITH ESTRADIOL BENZOATE AFFECTS THE PROGRESSION OF VASCULARIZATION IN PREOVULATORY FOLLICLES

2014 ◽  
Vol 26 (1) ◽  
pp. 172
Author(s):  
E. K. N. Arashiro ◽  
D. S. Vieira ◽  
L. F. M. Pfeifer ◽  
L. G. B. Siqueira ◽  
L. S. A. Camargo ◽  
...  
Keyword(s):  
Blood Flow ◽  
Estradiol Benzoate ◽  
Wilcoxon Test ◽  
Saline Control ◽  
Control Group ◽  
Colour Doppler ◽  
Follicular Wave ◽  
Preovulatory Follicles ◽  
Doppler Signals ◽  
Oestradiol Benzoate

Ovarian changes in blood supply have been related to follicle growth and ovulation in cattle. The aim of the present study was to characterise the vascularization pattern of the preovulatory follicle in cows induced to ovulate with a timed AI (TAI) protocol using oestradiol benzoate. Follicular wave was synchronized in 18 crossbred cows (Holstein × Gir) with the following protocol: Day 0 (D0), insertion of an intravaginal device of progesterone (1 g, P4) and IM injection of oestradiol benzoate (2 mg, EB); D9, intravaginal P4 device was removed and all the animals received IM injections of cloprostenol (0.53 mg) and eCG (300 IU); D10, animals were randomly allocate into 2 groups, which received 1 mL of saline (control group) or 1 mg of EB (EB group). The vascularization of the largest follicle present in the ovaries was evaluated by colour Doppler ultrasonography immediately before treatment (0 h–0 h) and every 6 h thereafter, up to 84 h or until ovulation was detected. The colour Doppler signals present in the follicular wall were subjectively scored on a 1-to-5 scale (1: no or very few blood flow; 5: intense blood flow detected in most of the follicular wall). The colour Doppler evaluations were performed retrospectively using videos recorded at each examination. The interval from treatment to ovulation was compared by Wilcoxon test. Differences in the vascularization score were compared considering the effects of treatment and time using the PROC MIXED procedure of SAS (SAS Institute Inc., Cary, NC, USA). As expected, in cows treated with EB, ovulations tended to occur earlier (48.0 ± 4.5 h v. 54.0 ± 7.1 h; P = 0.055) and were more synchronous (42–54 h, CV of 9.4% v. 42–66 h, CV of 13.3%) than in the control group. In both groups, follicular vascularization score progressively increased (P < 0.001) until ovulation. However, the vascularization score was lower (P < 0.05) in the EB group than in the control group during the 48-h period before ovulation (overall mean of 2.5 ± 0.7 and 3.0 ± 0.6, respectively); consequently, follicles of cows treated with EB ovulated with a lower vascularization score than did those in the control group (3.6 ± 0.5 v. 4.0 ± 0.5, respectively). Four cows (2 of each group) did not ovulate; follicle vascularization score in these cows remained below 2 during all the evaluation period. In conclusion, although an increase in blood flow is required for ovulation, EB-induced ovulations will occur and are associated with a reduced follicle vascularization. This difference may be related to the smaller interval from treatment to ovulation. Embrapa, CNPq, and Fapemig (CVZ PPM 0067/11) are acknowledged.

164 Gonadotrophin-releasing hormone injection and colour flow Doppler ultrasound of the preovulatory follicle as a tool to increase pregnancy outcome after timed AI in beef cows

2020 ◽  
Vol 32 (2) ◽  
pp. 209
Author(s):  
L. Pfeifer ◽  
J. Andrade ◽  
E. Moreira ◽  
G. Silva ◽  
V. Souza ◽  
...  
Keyword(s):  
Blood Flow ◽  
Color Doppler ◽  
Prostaglandin F2α ◽  
Beef Cows ◽  
Pregnancy Rates ◽  
Doppler Imaging ◽  
Preovulatory Follicle ◽  
Colour Doppler ◽  
Releasing Hormone ◽  
Gonadotrophin Releasing Hormone

The aims of this study were to determine (1) the association between Doppler vascularisation scores (DVS) of the preovulatory follicle (POF) and fertility of beef cows submitted to timed AI (TAI) and (2) whether cows with low DVS benefit from a gonadotrophin-releasing hormone (GnRH) treatment at TAI. Multiparous lactating Nelore cows (Bos indicus; n=69) from a commercial beef farm in the state of Rondônia, Brazil, were enrolled in this study. Cows received 2mg of oestradiol benzoate intramuscularly (Bioestrogen, Biogénesis Bagó) and an intravaginal progesterone-releasing device (1.9g of progesterone; controlled internal drug release, CIDR) to synchronise follicular wave emergence on Day 0. The CIDR device was removed and cows were treated with 150μg of D-cloprostenol intramuscularly (prostaglandin F2α analogue; Croniben), 1mg of oestradiol cypionate intramuscularly, and 300IU of equine chorionic gonadotrophin (Novormon) intramuscularly on Day 8. Cows were then painted with a tail chalk marker to identify those displaying oestrus. All cows were submitted to TAI 48h after CIDR removal. At TAI, occurrence of oestrus was recorded and all cows were examined using transrectal ultrasonography. Blood flow of the POF was evaluated using colour Doppler imaging. Colour Doppler signals present on the follicular wall were subjectively scored using a 1-to-4 scale (1=absence or very low blood flow, and 4=intense blood flow detected on most of the follicular wall surface) adapted from Ginther (2007Ultrasonic Imaging and Animal Reproduction: Color-Doppler Ultrasonography, pages 87-114). Then, cows were divided into three groups according their DVS of the POF: (1) high DVS (DVS ≥3; n=36), (2) low DVS (DVS &lt;3; n=16), and (3) low DVS (DVS &lt;3; n=17) plus a GnRH treatment at TAI. The diameter of the POF was analysed using analysis of variance (PROC GLIMMIX of SAS; SAS Institute Inc.), and the means were compared among groups using Tukey's test. The proportion of cows that displayed oestrus and pregnancy rates was analysed using chi-square test. Cows in the high-DVS group had a larger POF than cows in the low-DVS and low-DVS-GnRH groups (13.2±0.2, 11.7±0.5, and 12.2±0.4, respectively; P&lt;0.05). The proportion of cows that displayed oestrus was greater (P&lt;0.05) in the high-DVS group (72%, 26/36) than in the low-DVS (37.5%, 6/16) or low-DVS-GnRH (53%, 9/17) groups. Finally, greater (P&lt;0.05) pregnancy rates were observed in cows from the high-DVS (47.2%; 17/36) and low-DVS-GnRH (52.9%; 9/17) groups than in cows from the low-DVS group (18.7%; 3/16). The preliminary results from this study demonstrated that diameter of POF is positively associated with DVS. Moreover, cows that presented POF with higher DVS are more likely to become pregnant, and the administration of GnRH to females with low DVS can increase the fertility of beef cows submitted to TAI protocols. This study received funding support from Embrapa (MP1/PC3 project no. 01.03.14.011.00.00) and from CNPq (universal project no. 407307/2016-8).

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