scholarly journals Relationship between metabolic hormones and ovulation of dominant follicle during the first follicular wave post-partum in high-producing dairy cows

Reproduction ◽  
2007 ◽  
Vol 133 (1) ◽  
pp. 155-163 ◽  
Author(s):  
Chiho Kawashima ◽  
Saori Fukihara ◽  
Mayumi Maeda ◽  
Etsushi Kaneko ◽  
Carlos Amaya Montoya ◽  
...  
Keyword(s):  
Blood Flow ◽  
Dairy Cows ◽  
Ovarian Function ◽  
Post Partum ◽  
Plasma Concentrations ◽  
Reproductive Hormones ◽  
Follicular Growth ◽  
Dominant Follicle ◽  
Follicular Wave ◽  
Igf I

Recent studies suggest that IGF-I is a crucial regulatory factor in follicular growth during earlypost-partumperiod. The aim of the present study was to determine in detail the changing profiles of metabolic and reproductive hormones in relation to ovulation of the dominant follicle (DF) of the first follicular wavepost-partumin high-producing dairy cows. Plasma concentrations of related hormones in 22 multiparous Holstein cows were measured from 4 weeks pre-partum to 3 weekspost-partum, and the development of DF was observed with colour Doppler ultrasound. Thirteen cows showed ovulation by 15.2 dayspost-partum. Anovulatory cows showed higher GH and lower IGF-I levels than those in ovulatory cows during the peri-partum period. Each DF developed similarly, and a clear blood flow in the follicle wall was observed despite ovulation or anovulation. In addition, detailed endocrine profiles were analyzed in 9 out of the 22 cows. Five cows showed an increase in plasma oestradiol-17β (E2) with follicular growth followed by E2 peak, LH surge and ovulation. In these cows, plasma IGF-I concentrations remained high until 10 dayspost-partumfollowed by a gradual decrease. Subsequently, the insulin level increased together with the E2 peak towards ovulation. These profiles were not observed in anovulatory cows. In conclusion, our data strongly support the concept that IGF-I and insulin represent ‘metabolic signals’ of the resumption of ovarian functionpost-partumin high-producing dairy cows. Moreover, we provide the first visual evidence that both ovulatory and anovulatory DFs of the first follicular wavepost-partumare similarly supplied with active blood flow.

Physiological Adaptations to Milk Production that Affect the Fertility of High Yielding Dairy Cows

2004 ◽  
Vol 29 ◽  
pp. 37-71 ◽  
Author(s):  
V. J. Taylor ◽  
D. E. Beever ◽  
D. C. Wathes
Keyword(s):  
Dairy Cows ◽  
Milk Production ◽  
Ovarian Function ◽  
Post Partum ◽  
Reproductive Function ◽  
Influential Factors ◽  
Corpora Lutea ◽  
Expected Time ◽  
Physiological Adaptations ◽  
Igf I

SummaryThe high yielding dairy cow is expected to produce a substantial milk output every year and at the same time to conceive and maintain a pregnancy to term. To fulfil lifetime production potential a balance between yield, fertility and other influential factors has to be achieved. Any inability on the part of the management system to identify and rectify problems or on the part of the cow to cope with metabolic demands invariably results in economic or welfare issues. Our studies of high yielding dairy cows have revealed that some animals are capable of normal reproductive function whilst others are classic repeat breeders (requiring 3+ services per conception) or simply fail to rebreed. It is well established that the somatotrophic axis (growth hormone and insulin-like growth factors) drives lactation in ruminants but it is also intimately involved in reproductive processes. An awareness of metabolic adaptations to lactation that impact on reproduction in dairy cows is needed for appropriate management.The objective of our studies was to explore the metabolic profiles of high yielding dairy cows to identify factors influencing their ovarian function and fertility, hence to characterise the physiological adaptations involved. Our studies revealed different relationships between progesterone profile categories and metabolic status post partum. Delayed ovulation (DOV) or persistent corpora lutea (PCL) may be an appropriate response to a nutritional state or physiological situation and it may therefore be inaccurate to refer to these as ‘abnormal’. Whilst associated with high milk yields, not all profile categories detrimentally affected fertility parameters. Delayed ovulation postcalving (DOV1) was identified as the most prevalent abnormal profile encountered in first lactation high yielding cows. This may have occurred because the cows were not yet physically mature and unable to sustain both milk production and growth. The condition lasted long enough (71 ± 8.3 days from calving) to have a detrimental impact on their overall fertility parameters and was associated with significant physiological changes, representative of tissue mobilisation. Although the incidence of persistent luteal phases (PCL1 and PCL2) in dairy cows is increasing, this condition was not found to have any substantial detrimental effects on fertility or production parameters of the primiparous or multiparous cows in these studies. The main reproductive problems in our high yielding primiparous and multiparous cows appeared to be a failure to ovulate and conceive at the expected time or to maintain a pregnancy. These situations were associated predominantly with high milk yields and low concentrations of plasma IGF-I. A failure to ovulate appears to occur when body reserves are mobilised to maintain milk yield at the expense of reproduction and seems most likely to occur in primiparous high yielding cows or those experiencing GH-resistance (low IGF-I) due to excessive body condition loss, reduced feed intakes and factors such as stress and disease. More detailed investigations of dietary means of increasing IGF-I and optimising insulin concentrations, targeted at important reproductive times, are required in high yielding dairy cows, to aid in their management.

scholarly journals Effects of a non-steroidal aromatase inhibitor on ovarian function in cattle

2012 ◽  
Vol 24 (4) ◽  
pp. 631 ◽  
Author(s):  
M. Jimena Yapura ◽  
Reuben J. Mapletoft ◽  
Jaswant Singh ◽  
Roger Pierson ◽  
Jonathan Naile ◽  
...  
Keyword(s):  
Aromatase Inhibitor ◽  
High Performance ◽  
Ovarian Function ◽  
Plasma Concentrations ◽  
Dominant Follicle ◽  
Follicular Wave ◽  
Chromatography Tandem Mass Spectrometry ◽  
Liquid Chromatography Tandem Mass ◽  
Arrest Growth ◽  
Phosphate Buffered Saline

Effects of the non-steroidal aromatase inhibitor letrozole on ovarian function in cattle were determined. The hypothesis that letrozole would arrest growth of the dominant follicle, resulting in emergence of a new follicular wave at a predictable post-treatment interval, was tested. Heifers were assigned randomly to four groups 4 days after follicular ablation (~2½ days after wave emergence) and given intravenous doses of 500 (n = 9), 250 (n = 10), or 125 µg kg–1 (n = 10) letrozole or phosphate-buffered saline (controls; n = 10). Blood was collected and ovarian structures were monitored daily by transrectal ultrasonography. Plasma concentrations of LH and FSH were measured by radioimmunoassay; plasma concentrations of letrozole were determined by high-performance liquid chromatography tandem mass spectrometry. A single intravenous dose of letrozole did not induce regression of the dominant follicle present at the time of treatment, nor did it directly affect FSH release. Conversely, treatment with letrozole increased endogenous concentrations of LH and extended the lifespan of the dominant follicle, which delayed the next FSH surge and subsequent follicular wave emergence. Letrozole continues to have potential as a non-steroidal treatment for controlling ovarian function in cattle.

Seasonal fertility differences in synchronised dairy cows: Ultrasonic, metabolic and endocrine findings

2012 ◽  
Vol 60 (1) ◽  
pp. 131-143 ◽  
Author(s):  
Orsolya Balogh ◽  
Hedvig Fébel ◽  
Gyula Huszenicza ◽  
Margit Kulcsár ◽  
Zsolt Abonyi-Tóth ◽  
...  
Keyword(s):  
Dairy Cows ◽  
Ovarian Function ◽  
Body Condition Score ◽  
Post Partum ◽  
Oocyte Quality ◽  
High Plasma ◽  
Nonesterified Fatty Acid ◽  
Plasma Nefa ◽  
Reducing Ability ◽  
Igf I

The aim of this study was to identify relationships among seasonal differences of fertility, metabolic parameters and appearance of irregular luteal forms in high-yielding dairy cows. Holstein-Friesian cows were put on the Provsynch regimen in winter (n = 10) and in summer (n = 10). Blood sampling (starting 35 days post partum) and rectal ultrasound examinations (starting post insemination) were carried out once a week in each examination period. Metabolic [plasma nonesterified fatty acid (NEFA) and beta-hydroxybutyrate (BHB) levels, ferric reducing ability of plasma (FRAP) and serum beta-carotene] and endocrine parameters [plasma thyroxine (T4), triiodothyronine (T3), insulin-like growth factor (IGF-I) and insulin levels] were measured. In summer, two cows were excluded from the study because of metritis and none of the remaining animals became pregnant, but 6 of the 8 cows had irregular luteal forms (ILF) on their ovaries. In winter, one cow was excluded because of metritis and 6 of the 9 cows became pregnant, while 2 of the 3 open cows had irregular luteal forms. In summer the mean plasma NEFA and BHB concentrations were significantly higher, while serum carotene and plasma IGF-I concentrations were significantly lower than in winter. The high plasma NEFA concentration found in summer seemed to be in association with the lower body condition score (BCS) caused by depressed appetite. In conclusion, statistical analysis supports the hypothesis that increased plasma NEFA and BHB and decreased plasma IGF-I concentrations may result in reduced fertility in summer. These changes may be associated with the more frequent appearance of ILFs and probably have a negative effect on ovarian function and/or oocyte quality.

scholarly journals Insulin increases 17β-estradiol production by the dominant follicle of the first postpartum follicle wave in dairy cows

Reproduction ◽  
2004 ◽  
Vol 127 (5) ◽  
pp. 537-545 ◽  
Author(s):  
S T Butler ◽  
S H Pelton ◽  
W R Butler
Keyword(s):  
Dairy Cows ◽  
Insulin Treatment ◽  
Ovarian Function ◽  
Negative Impact ◽  
Pulse Amplitude ◽  
Aromatase Activity ◽  
Early Lactation ◽  
Dominant Follicle ◽  
Nonesterified Fatty Acids ◽  
Follicular Wave

Prolonged anovulation following parturition has a negative impact on fertility in dairy cows. Insulin plays an important role in ovarian function in many species, and is profoundly depressed in dairy cows during early lactation. We hypothesized that hypoinsulinemia during early lactation represents a key indicator of nutritional status, resulting in delayed ovulation. Holstein cows (n = 10) were subjected to either a hyperinsulinemic–euglycemic clamp (INS) or saline infusion (CTL) for 96 h, beginning on day 10 after parturition during the first postpartum follicular wave. Insulin was infused continuously (0.3 μg/kg body weight per h) via a jugular catheter, and euglycemia was maintained by infusion of glucose. Circulating insulin concentrations were elevated 2.6-fold in INS cows compared with CTL cows (0.73 ± 0.026 vs 0.28 ± 0.026 ng/ml; P < 0.001). Insulin treatment did not affect (P > 0.05) luteinizing hormone (LH) pulse frequency, pulse amplitude or mean circulating LH. Circulating estradiol was elevated in INS cows (P < 0.01) and circulating testosterone also tended to be higher. The ratio of testosterone to estradiol was not different between treatments for the initial 30 h of infusion, but was significantly reduced thereafter in response to insulin (P < 0.01), suggesting that hyperinsulinemia increased follicular aromatase activity. Insulin treatment also resulted in reduced circulating nonesterified fatty acids, and increased circulating total and free insulin-like growth factor-I concentrations. Insulin infusion increased estradiol secretion by the dominant follicle of the first postpartum follicular wave in dairy cows, and this effect appears not to be mediated through changes in pulsatile LH release.

Endurance training effects on plasma hormonal responsiveness and sex hormone excretion

1984 ◽  
Vol 56 (6) ◽  
pp. 1453-1463 ◽  
Author(s):  
B. A. Bullen ◽  
G. S. Skrinar ◽  
I. Z. Beitins ◽  
D. B. Carr ◽  
S. M. Reppert ◽  
...  
Keyword(s):  
Ovarian Function ◽  
Plasma Concentrations ◽  
Bicycle Ergometer ◽  
Reproductive Hormones ◽  
Hormonal Changes ◽  
Stress Markers ◽  
Exercise Training Program ◽  
Acute Changes ◽  
A Prospective Study ◽  
Hormone Excretion

A prospective study of the hormonal effects of a moderate exercise training program (4-wk control, 8-wk training) was conducted in seven young women. Sixty-minutes continuous bicycle ergometer tests of fixed relative intensity were performed at the beginning, middle, and end of the training period. The capacity of these acute bouts of exercise to affect circulating levels of stress markers, reproductive hormones, and hormones with possible antireproductive potential was measured. In addition, the urinary excretion of reproductive hormones was monitored continuously via serial overnight urine collections. Within testing sessions, plasma concentrations of all stress markers and antireproductive hormones rose significantly. Across testing sessions, only beta-endorphin + beta-lipotropin and cortisol exhibited an increment in peak responses as training progressed. Plasma reproductive hormone levels showed insignificant acute changes, and cyclic menstruation and preovulatory gonadotropin surges continued in all subjects. However, ovarian function was disturbed in four subjects as evidenced by a decreased excretion of estriol, free progesterone, or both. Transient infertility is a known clinical accompaniment of hormonal changes of comparable subtlety.

scholarly journals Reduced progesterone concentration during growth of the first follicular wave affects embryo quality but has no effect on embryo survival post transfer in lactating dairy cows

Reproduction ◽  
2011 ◽  
Vol 141 (3) ◽  
pp. 333-342 ◽  
Author(s):  
Fernando A Rivera ◽  
Luís G D Mendonça ◽  
Gláucio Lopes ◽  
José E P Santos ◽  
Rolando V Perez ◽  
...  
Keyword(s):  
Dairy Cows ◽  
Estrous Cycle ◽  
Embryo Quality ◽  
Post Partum ◽  
Embryo Survival ◽  
Follicular Wave ◽  
Lactating Dairy Cows ◽  
Prostaglandin F ◽  
Donor Cows

Fertility of lactating dairy cows is associated with reduced progesterone (P4) concentration compared with nonlactating animals. The objective of the current study was to determine whether P4 during growth of the first follicular wave (FFW) affects embryo quality. Lactating Holstein cows at 33±3 days post partum were allocated to one of three treatments. Cows in the FFW and FFW with P4 (FFWP) treatments started the superstimulation protocol on day 1 of the estrous cycle and second follicular wave (SFW) cows started the superstimulation protocol on estrous cycle day 7. Cows were superstimulated with 400 mg of NIH-FSH-P1 (FSH) given twice daily for 5 days, two prostaglandin F2α (PGF2α) injections given with the ninth and tenth injections of FSH, GNRH given 48 h after the first PGF2α injection, and timed insemination 12 and 24 h after the GNRH injection. Cows in the FFWP treatment received two intravaginal P4 inserts during the superstimulation. Embryos were recovered 6.5 days after artificial insemination and excellent/good and fair embryos were frozen and transferred. Blood was sampled daily from estrous cycle day 0 until insemination from donor cows. During the superstimulation protocol, P4 was (P<0.01) greatest for SFW cows followed by FFWP and FFW cows respectively. The percentage of embryos–oocytes from SFW and FFWP cows classified as excellent/good and fair embryos was (P=0.02) greater than those of FFW cows. Pregnancy per embryo transfer was not (P≥0.73) affected by embryo donor treatment. Reduced embryo quality of cows induced to ovulate the follicles from the first follicular wave is a consequence of reduced P4 during follicle growth.

115 FOLLICULAR GROWTH AND BLOOD FLOW OF THE DOMINANT FOLLICLE IN CROSSBRED RECIPIENTS TREATED WITH eCG

2014 ◽  
Vol 26 (1) ◽  
pp. 171
Author(s):  
M. P. Palhao ◽  
N. S. Junior ◽  
C. R. B. Guimarães ◽  
C. A. C. Fernandes ◽  
M. E. O. Ferreira ◽  
...  
Keyword(s):  
Blood Flow ◽  
Pregnancy Rate ◽  
Embryo Transfer ◽  
Sao Paulo ◽  
Ovulation Rate ◽  
São Paulo ◽  
Follicular Growth ◽  
Dominant Follicle ◽  
Follicle Diameter ◽  
Transfer Protocol

This study aimed to explore changes in follicle diameter and blood flow of the dominant follicle (DF), in ovulation and embryo transfer rates, after inclusion of eCG in a protocol for timed embryo transfer. The effect presence or absence of a corpus luteum (CL) at the start of treatment was also included. Crossbred heifers (n = 116, Bos taurus × Bos indicus), with (n = 61) or without (n = 55) CL, were included in the same hormone protocol: Day 0 (D0), insertion of progesterone (P4) device (1.0 g, Sincrogest®, Ouro Fino, São Paulo, Brazil) and 2 mg of oestradiol benzoato (EB, Sincrodiol®, Ouro Fino); D8, removal of P4 device and injection of sodium Cloprostenol (0.250 mg mL–1, Sincrocio®, Ouro Fino). On D8, the animals with and without CL – at the beginning of the protocol – were equally divided into 2 groups (G): G1 – injection of 300 IU (2.0 mL) of eCG (n = 56; Synchro eCG®, Ouro Fino); G2 – 2.0 mL of saline (n = 60). The ovulations were synchronized with 1 mg of EB on D9. From D8 to D11, the diameter of the DF and blood flow in its wall were recorded daily (M5 ultrasound with colour Doppler technology, 7.5-MHz linear array, DPS medical equipment, São Paulo, Brazil). Approximately 100 frames in colour-flow mode, containing entire cross-sections of the DF, were recorded during each examination. The area of the follicular wall with coloured pixels was measured with ImageJ software (Image Processing and Analysis in Java) from the frame with the largest blood flow signal. Before embryo transfer, all heifers were evaluated, and those with good-quality CL received frozen/thawed embryos (ethylene glycol 1.5 mol). Follicle diameter and blood flow area were compared between groups with or without CL before timed embryo transfer protocol and between eCG treatments. The PROC GLM procedure of SAS (version 9.0) and the t-test were used to assess the differences between means. Pregnancy diagnosis was performed on D35. Embryo transfer (ET) rate of the recipients and pregnancy rate were compared between CL or eCG treatments by the chi-squared test. Ovarian status, before hormone protocol, did not change (P > 0.05) the follicular growth of the DF. However, ovulation rate (78.8 v. 65.4%, P < 0.05) and ET rate (78.7 v. 65.4%, P < 0.05) were higher in animals with CL on D0. From D8 to D10, the inclusion of eCG did not affect (P > 0.05) follicular growth and blood flow of the DF. The time effect (P < 0.0001) for follicular blood flow had shown an increase in area of blood flow 24 h after implant removal (7.7 ± 0.7,b 10.2 ± 0.7,a and 12.3 ± 1.0a mm2, for Days 8, 9, and 10, respectively). The eCG did not affect (P > 0.05) the ovulation rate (71.4 and 73.3%, respectively, eCG and no eCG), however, approached an increased (P < 0.06) ET rate (78.8 v. 66.7%). The overall pregnancy rate (51.2%, 43/84) was not affected (P > 0.05) by evaluated variables. In summary, the addition of 300 IU of eCG on D8 of the timed embryo transfer protocol did not change the development of DF but increased the ET rate of the recipients. Biotran, FAPEMIG (project number APQ-1454-12), and CnPQ are acknowledged.

164 EFFECT OF OVULATION-INDUCING FACTOR (OIF) ON OVARIAN FUNCTION IN CATTLE

2008 ◽  
Vol 20 (1) ◽  
pp. 162 ◽  
Author(s):  
M. D. Van Steelandt ◽  
V. M. Tanco ◽  
M. H. Ratto ◽  
G. P. Adams
Keyword(s):  
Seminal Plasma ◽  
Ovarian Function ◽  
Bos Taurus ◽  
Suppressive Effect ◽  
Positive Control ◽  
Negative Control ◽  
Dominant Follicle ◽  
Wave Dynamics ◽  
Follicular Wave ◽  
As Species

Systemic administration of ovulation-inducing factor (OIF), discovered recently in seminal plasma of llamas, alpacas (induced ovulators), and cattle (spontaneous ovulators), stimulated ovulation in >90% of female llamas and alpacas. The objective of the present study was to test the hypothesis that purified OIF from llama seminal plasma would induce ovulation in cattle. Peripubertal heifers, weighing 323 � 27 kg, were used to minimize the confounding effect of spontaneous ovulation. Heifers (n = 11/group) were treated intramuscularly with 1.0 mg/100 kg of purified OIF, 100 µg of GnRH (positive control), or 2.5 mL of phosphate-buffered saline (negative control). Ovarian dynamics were monitored daily by transrectal ultrasonography for 10 days post-treatment. Blood samples were collected at 0.5- to 1-h intervals for 8 h, beginning at the time of treatment. Ovulation occurred in 9/11 (82%) of GnRH-treated heifers and in 1/11 (9%) heifers in each of the OIF- and saline-treated groups (P < 0.05). A surge in plasma LH concentration was detected within 30 min of treatment in the GnRH group (2.2 � 0.1 ng mL–1; P < 0.05), but remained at the basal level in the OIF- and saline-treated groups (0.3 � 0.1 and 0.2 � 0.1 ng mL–1, respectively). The onset of regression of the dominant follicle present at the time of treatment was earlier (P < 0.05) in OIF- v. saline-treated heifers (3.1 � 0.6 days v. 6.0 � 0.7 days). The interval from treatment to follicular wave emergence was shorter (P < 0.05) in GnRH- and OIF-treated heifers than in those treated with saline (1.1 � 0.4 days, 1.5 � 0.3 days, and 3.1 � 0.3 days, respectively). A similar pattern was observed for emergence of the second follicular wave (5.1 � 0.7 days, 4.6 � 0.5 days, and 6.6 � 0.4 days, respectively). Purified OIF did not induce ovulation in heifers but hastened both the regression of the extant dominant follicle and follicular wave emergence. Results provide a rationale for the hypothesis that OIF from seminal plasma is involved in controlling follicular wave dynamics in spontaneously ovulating species (e.g., Bos taurus) through a suppressive effect on the dominant follicle. The mechanism of action on ovarian follicular wave dynamics, as well as species specificity, remains to be elucidated.

175 FOLLICULAR DEVELOPMENT AND OVARIAN BLOOD FLOW IN MARES WITH EARLY OR LATE OVULATION POSTPARTUM

2015 ◽  
Vol 27 (1) ◽  
pp. 178
Author(s):  
K. M. Lemes ◽  
L. A. Silva ◽  
E. C. C. Celeghini ◽  
M. A. Alonso ◽  
G. Pugliesi ◽  
...  
Keyword(s):  
Blood Flow ◽  
Postpartum Period ◽  
Follicular Development ◽  
Ovarian Activity ◽  
Follicle Development ◽  
Follicular Growth ◽  
Dominant Follicle ◽  
Vascular Perfusion ◽  
Early Postpartum ◽  
Linear Probe

The postpartum period is characterised by the rapid uterine involution process and return of ovarian activity (foal heat), resulting in a fertile oestrus in most of the mares. However, the follicular development and selection processes during this period are not completely known in horses. We aimed to study the characteristics of follicular growth and vascular perfusion in the ovary during the early postpartum period in mares that demonstrated oestrous behaviour and had early (<10 days) or late (≥10 days) ovulation. Ten mares were scanned daily from the first day postpartum (Day 1) until the day of the first postpartum ovulation (Day 0). The animals were split in the early (n = 3) and late (n = 7) ovulation groups (averaged interval between parturition and ovulation: 8.0 ± 0.0 and 14.7 ± 1.2 days, respectively). For ultrasound exams a Duplex B-mode and colour Doppler instrument (M5VET®, Mindray, Shenzhen, China) was used with a multifrequency linear probe. Data were analysed for the main effects of group, day, and their interaction using the PROC MIXED procedure of SAS software (version 9.3, SAS Institute Inc., Cary, NC, USA). For the follicular growth, no difference (P > 0.05) was detected between the groups when the data were analysed for the days relative to ovulation (from Day 7 to Day 1). However, the dominant follicle was larger (P < 0.05) in the early-ovulated group (37.2 ± 1.6 v. 21.9 ± 1.1) in all days during early postpartum (Day 1 to Day 7). The number of follicles with >25 mm diameter was also greater (P < 0.05) in the early-ovulated group (1.1 ± 0.1 v. 0.1 ± 0.1) during the first 3 days postpartum. In addition, the late-ovulated mares showed greater number of follicles with 20–25 mm during Day 4 to Day 7 (2.0 ± 0.2 v. 0.7 ± 0.1). For the blood flow characteristics, no difference (P > 0.05) was detected in the coloured signals of blood flows in the follicular wall of the dominant follicle or in the ovarian pedicle ipsilateral to the largest follicle. Therefore, the characteristics of the follicle growth on the preceding days of ovulation were similar between the early- and late-ovulated mares and consistent with the follicular dynamics expected in non-pregnant and non-lactating mares. However, when the data were analysed for the days relative to parturition, a greater follicle development was present in mares that ovulate earlier during the postpartum period (<10 days). In conclusion, the results suggest that important events may occur previous to the parturition, resulting in an early follicle development, mainly in those mares that show heat signs and ovulate within 10 days postpartum. Research was supported by FAPESP process number 2010/10692-9 and CNPq process number 135954/2011-8.

252 THE ROLE OF INSULIN-LIKE GROWTH FACTOR 1 (IGF-1) IN DEVELOPMENT OF AN ESTROGEN-ACTIVE DOMINANT FOLLICLE DURING THE FIRST FOLLICULAR WAVE POSTPARTUM IN DAIRY COWS

2007 ◽  
Vol 19 (1) ◽  
pp. 242
Author(s):  
C. Kawashima ◽  
N. Sudo ◽  
C. Amaya Montoya ◽  
E. Kaneko ◽  
M. Matsui ◽  
...  
Keyword(s):  
Dairy Cows ◽  
Repeated Measures ◽  
Follicular Development ◽  
High Plasma ◽  
T Test ◽  
Dominant Follicle ◽  
High Concentration ◽  
Follicular Wave ◽  
Follicle Diameter ◽  
High Level

Recent studies have shown that IGF-1 is a crucial factor for ovarian follicular development in mammals. In postpartum (pp) dairy cows, plasma IGF-1 and estradiol (E2) levels in ovulatory cows at the first follicular wave pp are higher than in anovulatory cows. However, the plasma IGF-1 profile in an ovulatory or anovulatory dominant follicle (DF), which have different E2 production, at the first follicular wave pp have not yet been elucidated. Thus, we investigated the changing profile of plasma IGF-1 levels during first follicular wave pp. In 22 multiparous Holstein cows, blood samples were obtained 2 times/week from 4 weeks prepartum to 3 weeks pp, and the first follicular wave was monitored by ultrasound 2 times/week from 7 days pp to ovulatory phase. Detailed IGF-1 profiles in blood were determined during DF growth and maturation 4 times/day from 10 days pp to 7 days after the first ovulation in 5 ovulatory cows and to 20 days pp in 4 anovulatory cows; the data were analyzed by repeated measures ANOVA, and Student&apos;s t-test. There was no interaction between groups and time within the prepartum or the pp period. The ovulatory cows (n = 13/22) with an estrogen-active dominant (EAD: high plasma E2 level with peak) follicle showed higher IGF-1 levels than anovulatory cows (n = 9/22) with an estrogen-inactive dominant (EID: low plasma E2 level without peak) follicle during the prepartum (117 � 8 vs. 91 � 5 ng mL-1; P &lt; 0.05) and the pp (91 � 4 vs. 64 � 4 ng mL-1; P &lt; 0.001) period. Especially noteworthy, during the first follicular wave pp in ovulatory cows, the plasma IGF-1 levels were maintained at a high level until E2 levels increased, followed by an LH surge. We observed that the EAD follicle in ovulatory cows ovulated. To further examine the IGF-1 system in the intra-follicular environment, we used the EAD and EID follicles from ovaries of dairy cows obtained at a slaughterhouse. The EAD and EID follicles were classified on the basis of follicle diameter and E2 concentrations in follicular fluid (FF). The significant differences of factors between EAD and EID were analyzed by Student&apos;s t-test. The expression of IGF-1 mRNA was not detected in follicular cells in either EAD and EID, suggesting that IGF-1 in FF is mainly derived from liver. The free IGF-1 levels in FF in EAD (4.8 � 0.5 ng mL-1) were higher than those in EID (2.7 � 0.1 ng mL-1; P &lt; 0.05). In addition, the expression of type 1 IGF receptor (IGFR-1) mRNA in EAD was higher than hat in EID (P &lt; 0.0001). From the results of the present study, it is apparent that the EAD follicle during the first follicular wave pp in ovulatory cows sufficiently expressed IGFR-1, and a liver-derived IGF-1 stimulates E2 production in the follicle to ovulate. In conclusion, our data suggest that a high concentration of IGF-1, secreted from the liver, during the peripartum period may be one of important factors for the appearance of an ovulatory follicle during the first follicular wave pp cows.

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