207 EFFECT OF LOCATION AND STAGE OF THE DOMINANT FOLLICLE ON OVULATION AND PREGNANCY RATES IN ALPACAS

2010 ◽  
Vol 22 (1) ◽  
pp. 261
Author(s):  
M. Cervantes ◽  
W. Huanca ◽  
A. Cordero ◽  
M. Guerra ◽  
X. P. Valderrama ◽  
...  
Keyword(s):  
Pregnancy Rate ◽  
Ovarian Follicle ◽  
Ovarian Response ◽  
Pregnancy Rates ◽  
Left Ovary ◽  
Ovulation Rate ◽  
Dominant Follicle ◽  
Embryo Survival ◽  
Ovarian Follicle Development ◽  
Stage Of Development

Gestation in camelids occurs in the left horn regardless of whether ovulation has taken place in the left or right ovary, suggesting uterine embryo migration (Fernandez-Baca S et al. 1970 Biol. Reprod. 3, 243-251). On the other hand, we have previously documented (Ratto MH et al. 2003 Theriogenology 60, 1645-1656) that more than 90% of llamas with the presence of a follicle ≥6 to 7 mm in diameter, regardless of their stage of development, did accept the copula and ovulate after mating. However, it is unknown whether these oocytes are competent to achieving acceptable pregnancy rate. This study was designed to determine the effect of location of the preovulatory dominant follicle (right or left ovary) on ovulation and pregnancy rates and to evaluate the effect of stage of ovarian follicle development at mating (growing, maintenance, and regression) on ovulation rate and embryo survival in alpacas. In Experiment 1, nonlactating alpacas (4-6 years of age) weighing 55 to 75 kg were randomly assigned to 1 of 2 groups according to the location of the dominant follicle detected by ultrasonography: right ovary [right dominant follicle (RDF); n = 96] or left ovary [left dominant follicle (LDF); n = 108]. Ovulation and pregnancy diagnoses were assessed by ultrasonography on Days 2 (Day 0 = mating) and 30, respectively. Ovulation was defined as the sudden disappearance of a large follicle (≥6 mm) that was detected during the ultrasonographic examination 24 to 36 h after mating. Ovulation rates (96.5 and 96.3% for RDF and LDF, respectively) and pregnancy rates (60.2 and 56.7% for RDF and LDF, respectively) rates did not differ (P = 0.9) among groups. In Experiment 2, nonlactating alpacas (4-8 years of age) weighing 60 to 80 kg (n = 4116) were submitted to ultrasound-guided follicle ablation to synchronize follicular wave emergence and, after daily ultrasonography examination, were randomly assigned to the following groups according to the growth phase and diameter of the dominant follicle: early growing (G1; 5-6 mm, n = 27), mid-growing (G2; 7-12 mm, n = 30); static (G3; 7-12 mm, n = 430), or regressing (G4; 12-7 mm, n = 29). All alpacas were mated with a proven male, except 5 alpacas from G1 that rejected the sire. The ovarian response was determined by ultrasound examinations that were carried out on Day 2 (ovulation rate), Day 9 (CL size), and Day 35 (presence of embryonic vesicle or embryo). Ovulation was determined as described in Experiment 1. No differences were detected in ovulation rate among groups (95, 96, 100, and 96%, respectively; P = 0.8) or in CL size (10.3 ± 0.8; 11.7 ± 0.6; 11.1 ± 0.8; and 11.1 ± 0.9 mm, respectively; P = 0.6). Pregnancy rate was highest in G2 (65.5%), intermediate in G1 (52.4%) and G3 (53.3%), and lowest in G4 (42.9%; P < 0.05). Results suggest that location of the dominant follicle has no influence on ovulation and pregnancy rates and that although mating during the regressing phase of the dominant follicle has no effect on ovulation, pregnancy rate may be compromised. This study was supported by DID-UACH, Universidad Austral de Chile.

scholarly journals Association between ovarian follicle development and pregnancy rates in dairy cows undergoing spontaneous oestrous cycles

Reproduction ◽  
2004 ◽  
Vol 127 (5) ◽  
pp. 621-629 ◽  
Author(s):  
Emma C L Bleach ◽  
Richard G Glencross ◽  
Philip G Knight
Keyword(s):  
Dairy Cows ◽  
Pregnancy Rate ◽  
Ovarian Follicle ◽  
Pregnancy Rates ◽  
Developmental Competence ◽  
Follicle Development ◽  
Ovarian Follicle Development ◽  
Ovulatory Follicle ◽  
Ovulatory Follicles ◽  
First Time

Ovarian follicle development continues in a wave-like manner during the bovine oestrous cycle giving rise to variation in the duration of ovulatory follicle development. The objectives of the present study were to determine whether a relationship exists between the duration of ovulatory follicle development and pregnancy rates following artificial insemination (AI) in dairy cows undergoing spontaneous oestrous cycles, and to identify factors influencing follicle turnover and pregnancy rate and the relationship between these two variables. Follicle development was monitored by daily transrectal ultrasonography from 10 days after oestrus until the subsequent oestrus in 158 lactating dairy cows. The cows were artificially inseminated following the second observed oestrus and pregnancy was diagnosed 35 days later. The predominant pattern of follicle development was two follicle waves (74.7%) with three follicle waves in 22.1% of oestrous cycles and four or more follicle waves in 3.2% of oestrous cycles. The interval from ovulatory follicle emergence to oestrus (EOI) was 3 days longer (P < 0.0001) in cows with two follicle waves than in those with three waves. Ovulatory follicles from two-wave oestrous cycles grew more slowly but were approximately 2 mm larger (P < 0.0001) on the day of oestrus. Twin ovulations were observed in 14.2% of oestrous cycles and occurred more frequently (P < 0.001) in three-wave oestrous cycles; consequently EOI was shorter in cows with twin ovulations. Overall, 57.0% of the cows were diagnosed pregnant 35 days after AI. Linear logistic regression analysis revealed an inverse relationship between EOI and the proportion of cows diagnosed pregnant, among all cows (n = 158; P < 0.01) and amongst those with single ovulations (n = 145; P < 0.05). Mean EOI was approximately 1 day shorter (P < 0.01) in cows that became pregnant than in non-pregnant cows; however, pregnancy rates did not differ significantly among cows with different patterns of follicle development. These findings confirm and extend previous observations in pharmacologically manipulated cattle and show, for the first time, that in dairy cows undergoing spontaneous oestrous cycles, natural variation in the duration of post-emergence ovulatory follicle development has a significant effect on pregnancy rate, presumably reflecting variation in oocyte developmental competence.

scholarly journals The Effect of A PRID®Delta-Based Estrus Synchronization Protocol On Pregnancy Rates In Cows With No Estrus Symptoms

2022 ◽  
Author(s):  
Murat Can Demir ◽  
Cihan Kaçar ◽  
Umut Çağın Arı ◽  
Semra Kaya ◽  
Oğuz Merhan ◽  
...  
Keyword(s):  
Pregnancy Rate ◽  
Artificial Insemination ◽  
Prostaglandin F2α ◽  
Pregnancy Rates ◽  
Dominant Follicle ◽  
Serum Progesterone ◽  
Blood Samples ◽  
Follicle Diameter ◽  
Follicle Size ◽  
Equine Chorionic Gonadotropin

Abstract The present study aimed to determine the effects of progesterone-based gonadotropin-releasing hormone (GnRH), prostaglandin F2α (PGF2α), and equine chorionic gonadotropin (eCG) injections on progesterone profiles and pregnancy rates in cows with no estrus symptoms within 60 days after parturition. A total of 80 cows were included in the study. All animals had the progesterone-releasing device PRID®Delta placed intravaginally for nine days with an injection of GnRH. On the eighth day, PGF2α was injected, and PRID®Delta was removed from the vagina on day nine. Artificial insemination was carried out 60 hours after PRID®Delta removal. In half of the animals (n = 40), 600 IU of eCG was injected when PRID®Delta was removed on the ninth day before artificial insemination 60 hours later. Blood samples were taken from the tail vein on days 0 and 8 to determine progesterone levels. The pregnancy rate in the group that received eCG was 37.5%, while it was 27.5% in those that did not (P = 0.4). While the dominant follicle diameter was 15.5 mm in cows injected with eCG during timed artificial insemination, the follicle diameter was 12.4 mm in cows with no eCG injection (P <0.001). There were no differences in serum progesterone values in blood samples taken until the time of artificial insemination. However, progesterone values in the blood taken during artificial insemination were 0.94 ng/ml in the eCG- group and 0.72 ng/ml in the eCG+ group (P <0.05). As a result, it was determined that eCG injections, in addition to progesterone-based GnRH and PGF2α applications, increased the pregnancy rates in cows without symptoms of estrus. The dominant follicle diameter was larger in cows treated with eCG during artificial insemination; however, follicle size did not increase the pregnancy rate.

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.

116 PREGNANCY RATES AFTER ADMINISTRATION OF EQUINE CHORIONIC GONADOTROPIN (eCG) AT PROGESTERONE INTRAVAGINAL DEVICE REMOVAL AND 14 DAYS AFTER FIXED-TIME AI IN BEEF CATTLE

2011 ◽  
Vol 23 (1) ◽  
pp. 163 ◽  
Author(s):  
R. Núñez ◽  
T. de Castro ◽  
L. Cutaia ◽  
G. Bó ◽  
A. Menchaca
Keyword(s):  
Beef Cattle ◽  
Pregnancy Rate ◽  
Body Condition Score ◽  
Fetal Loss ◽  
Fixed Time ◽  
Pregnancy Rates ◽  
Control Group ◽  
Device Removal ◽  
Embryo Survival ◽  
Intravaginal Device

An important proportion of embryonic deaths in cattle occur during the critical period of embryo development and maternal recognition of pregnancy. High serum progesterone concentrations during this period are associated to higher embryo survival, and the use of eCG could enhance luteal activity. Two experiments were carried out to evaluate the effect of administering eCG at the time of removal of a progesterone-releasing device and 14 days after fixed-time artificial insemination (FTAI) in beef cattle. Multiparous suckled cows between 60 and 90 days postpartum (n = 297; Exp. 1), and two-year old prepuberal heifers (n = 689; Exp. 2) with a body condition score (BCS) between 3.5 and 5 (1 to 8 scale) were used. At the beginning of the experiments, none of females used had a corpus luteum detected by ultrasonography. Females received an intravaginal device containing 0.5 g progesterone (DIB 0.5, Syntex, Buenos Aires, Argentina) and 2 mg oestradiol benzoate i.m. (Benzoato de Oestradiol, Syntex). Eight days later, 500 μg of cloprostenol (Ciclase DL, Syntex) and 0.5 mg oestradiol cypionate (Cipiosyn, Syntex) were given i.m. and devices were removed; FTAI was performed 52 to 56 h after DIB removal. At the time of device removal, the animals were randomly allocated to 4 groups, to receive 400 IU of eCG i.m. (Novormon, Syntex) or placebo at device removal and/or 14 days after FTAI, in a 2 × 2 factorial design. Control group did not receive eCG. In Exp. 1, nose plates were placed on calves on the day of DIB insertion and left for 10 days in order to prevent suckling. Pregnancy diagnosis was performed by ultrasonography at 30 and 60 days after FTAI. Data were analysed by logistic regression. Pregnancy rate at 30 days after FTAI was affected by treatment (P < 0.05; Table 1). Late embryonic/fetal loss rates (non-pregnant females at 60 days after FTAI over those pregnant at 30 days) were 1.6% (3/182) for cows in Exp. 1 and 4.8% (14/292) for heifers in Exp. 2; no differences were detected among groups. In conclusion, administration of 400 IU of eCG at device removal increases pregnancy rate, both in anestrus cows and heifers. However, the administration of a second dose of eCG 14 days after FTAI suggests a possible effect on embryo survival within the first 30 days of pregnancy in cows but not in heifers. Further studies are required to confirm these results. Table 1.Pregnancy rates after administration of eCG at time of progesterone device removal and/or 14 days after insemination in beef cattle Supported by Syntex.

161 EFFECT OF MELOXICAM TREATMENT ON PREGNANCY RATES IN HOLSTEIN HEIFERS

2007 ◽  
Vol 19 (1) ◽  
pp. 197
Author(s):  
A. Guzeloglu ◽  
H. Erdem
Keyword(s):  
Corpus Luteum ◽  
Pregnancy Rate ◽  
Treated Group ◽  
Early Embryo ◽  
Pregnancy Rates ◽  
Control Group ◽  
Critical Stage ◽  
Embryo Survival ◽  
Flunixin Meglumine ◽  
Pregnancy Recognition

We previously reported that administration of flunixin meglumine two times at a critical stage approaching pregnancy recognition associated with corpus luteum maintenance increased early embryo survival and pregnancy rate via an additive antiluteolytic effect with the conceptus (Guzeloglu et al. 2006 Reprod. Fertil. Dev. 18, 183). In this study, the objective was to determine if a single administration of meloxicam, a non-steroid anti-inflammatory drug (NSAID) with a longer half-life, could be used instead of flunixin meglumine to avoid repeated injections in heifers at a critical stage following insemination to increase pregnancy rate due to its inhibitory effect on PGF2� synthesis. Eighty-five 15-18-month-old Holstein heifers were synchronized; following insemination (Day 0), the heifers were randomly assigned to receive a subcutaneous meloxicam injection (0.5 mg kg-1; n = 37) in the afternoon of Day 15 or left untreated as controls (n = 48). Pregnancy rates were defined as the percentage of heifers diagnosed pregnant by ultrasound between Days 31 and 38 after AI. The effect of treatment on pregnancy rates was analyzed by chi-square test. Meloxicam treatment on Day 15 after insemination dramatically decreased the pregnancy rates in the heifers (25 of 48 (52%) in the control group vs. 9 of 37 (24.3%) in the meloxicam-treated group; P &lt; 0.01). This result indicates that administration of meloxicam around a time associated with pregnancy recognition and corpus luteum maintenance was harmful to the pregnancy even though the drug is considered to be safe during pregnancy in cattle. It is concluded that direct or indirect effects of meloxicam on the uterine environment and/or embryo are not favorable at least during early pregnancy in cattle. How meloxicam exerted its detrimental effect on pregnancy warrants further investigation.

363 FACTORS INFLUENCING PREGNANCY RATES FOLLOWING TRANSFER OF BOVINE IN VIVO EMBRYOS BIOPSIED FOR SEX DETERMINATION

2007 ◽  
Vol 19 (1) ◽  
pp. 297
Author(s):  
S. Li ◽  
W. Yu ◽  
J. Fu ◽  
Y. Bai ◽  
F. Jin ◽  
...  
Keyword(s):  
Pregnancy Rate ◽  
Embryo Transfer ◽  
Pregnancy Rates ◽  
Chi Square ◽  
Embryo Survival ◽  
Chi Square Test ◽  
First Time ◽  
Fresh Embryos

Data collected from commercial embryo transfer programs in 63 farms in China during June 2002 to December 2005 was analyzed to examine the effects of various factors (biopsy, freezing, sample size, embryo development and quality, in vitro culture, and recipient quality) on pregnancy rates of in vivo-biopsied embryos. Embryos were flushed from superovulated dairy cattle and subjected to a biopsy for sexing determination using protocols and sexing kits supplied by AB Technology Ltd. Fresh embryos were implanted on the same day or frozen with AG freeze medium (AB Technology Ltd., Pullman, WA, USA) for later transfer. Recipients were synchronized with CIDA + PG protocols. Embryos were cultured in 6-well dishes containing 1.3 mL of holding medium (AB Technology Ltd.) in each well at room temperature (20–25�C) for examination of embryo survival in vitro. The chi-square test was used in statistic analysis. The implantation of fresh embryos after biopsy did not affect pregnancy rates (49.6%, 257/518) compared to that of non-biopsied fresh and frozen–thawed embryo groups (52.9%, 47/140 and 46.6%, 177/380, respectively). However, for biopsied embryos subjected to frozen and thawed procedures before implantation, particularly for those subjected to the removal of a larger biopsy, a reduced pregnancy rate was observed (41.8%, 297/710; P &lt; 0.01). Pregnancy rates among biopsied embryos at 3 different development stages (morula-early blastocyst, blastocyst, and expanded blastocyst) were not different. Similar results were found between embryo groups of grade 1 and 2. A significant decrease in pregnancy rate (0/10) was observed with embryos held in vitro for a longer period of time (&gt;5 h), suggesting detrimental effects of in vitro conditions on embryo survival. The highest pregnancy rate (68.0%) was observed in recipients synchronized for the first time before being implanted with biopsied embryos. Significant decreases in such rates were found in recipients synchronized for the second or third times or those with an abortion history at the first or second synchronization-implantation treatment (P &lt; 0.01). Better pregnancy rates (45.6%, 41/90; 46.1%, 76/165; and 45.5%, 5/11) were obtained for recipients implanted with biopsied embryos at Days 7.5, 8.0, and 8.5 post-heat detection, respectively, compared to 16% at Day 7 (3/18, P &lt; 0.05). It is concluded that mechanical treatment (cutting) does not reduce the survival of biopsied embryos; however, cryopreservation reduces their ability to survive in vivo. The analyses also suggest that holding embryos in vitro should not be longer than 5 h unless more favorable in vitro conditions can be provided. To achieve better results of implantation of biopsied embryos, embryo transfer should be performed during 7.5–8.5 days post-estrus, and the healthy recipients synchronized for the first time should be used.

Differential expression of signal transduction factors in ovarian follicle development: a functional role for betaglycan and FIBP in granulosa cells in cattle

2008 ◽  
Vol 33 (2) ◽  
pp. 193-204 ◽  
Author(s):  
N. Forde ◽  
M. Mihm ◽  
M. J. Canty ◽  
A. E. Zielak ◽  
P. J. Baker ◽  
...  
Keyword(s):  
Signal Transduction ◽  
Granulosa Cells ◽  
Ovarian Follicle ◽  
Growth Trajectories ◽  
Dominant Follicle ◽  
Quantitative Real Time Pcr ◽  
Differential Growth ◽  
Ovarian Follicle Development ◽  
Expression Of Genes

Ovarian follicles develop in groups yet individual follicles follow different growth trajectories. This growth and development are regulated by endocrine and locally produced growth factors that use a myriad of receptors and signal transduction pathways to exert their effects on theca and granulosa cells. We hypothesize that differential growth may be due to differences in hormonal responsiveness that is partially mediated by differences in expression of genes involved in signal transduction. We used the bovine dominant follicle model, microarrays, quantitative real-time PCR and RNA interference to examine this. We identified 83 genes coding for signal transduction molecules and validated a subset of them associated with different stages of the follicle wave. We suggest important roles for CAM kinase-1 and EphA4 in theca cells and BCAR1 in granulosa cells for the development of dominant follicles and for betaglycan and FIBP in granulosa cells of regressing subordinate follicles. Inhibition of genes for betaglycan and FIBP in granulosa cells in vitro suggests that they inhibit estradiol production in regressing subordinate follicles.

scholarly journals Serum Progesterone Level at the Day Prior to Frozen Thawed Embryo Transfer and Pregnancy Rate

2021 ◽  
pp. 221-231
Author(s):  
Merihan Mohamed Elewa ◽  
Ayman Abdelaziz Eldorf ◽  
Shahinaz Hamdy Elshorbagy ◽  
Manal Mostafa Abdallah
Keyword(s):  
Pregnancy Rate ◽  
Embryo Transfer ◽  
Endometrial Thickness ◽  
Pregnancy Rates ◽  
Observational Research ◽  
Embryo Survival ◽  
Serum Progesterone ◽  
Laboratory Methods ◽  
Frozen Thawed Embryo Transfer ◽  
Thawed Embryo Transfer

Background: Cryopreservation's success rate varies depending on woman age, as low as 14.8% (if eggs were extracted from 40-year-old women), and as high as 31.5% with 25-year-old women. The goal of the research is to improve laboratory methods for freezing-thawing embryos, leading to elevated embryo survival rate. Yet, in hormonal replacement therapy frozen-thawed embryo transfer (HRT-FET) cycles, effective endometrial preparation before embryo transfer attracted less focus. The present research’s aim is to see whether there's a link between blood progesterone levels and pregnancy rates the day before frozen-thawed embryo transfer. Methods: This prospective observational research has investigated 120 patients of frozen-thawed embryo transfer cycle treatment, only 100 individuals subdivided to 2 groups for serum level of progesterone one day before frozen-thawed embryo transfer. The subjects visited both the Obstetrical and Gynecological Department of Tanta University as well as private centers between May 2020 and January 2021. Results: We discovered no correlation between maternal age with pregnancy test results. Yet, our study discovered highly significant variation among both groups regarding endometrial thickness one day preceding embryo transfer, and regarding pregnancy rate (p<0.05). Conclusion: The serum progesterone hormone preceding frozen embryo transfer has significant and direct relation and impact upon pregnancy rates. The present research detected low serum progesterone less than 10 nanograms/ml in the day before frozen-thawed embryo transfer in HRT-FET cycles significantly decreased probability of ongoing pregnancy post frozen-thawed embryo transfer.

150 EFFECT OF TIMELY FLUNIXIN MEGLUMINE TREATMENT ON PREGNANCY RATES IN HOLSTEIN HEIFERS

2006 ◽  
Vol 18 (2) ◽  
pp. 183
Author(s):  
A. Guzeloglu ◽  
H. Erdem ◽  
M. K. Saribay ◽  
W. W. Thatcher ◽  
T. Tekeli
Keyword(s):  
Pregnancy Rate ◽  
Inhibitory Effect ◽  
Early Embryo ◽  
Pregnancy Rates ◽  
Control Group ◽  
Chi Square ◽  
Embryo Survival ◽  
Flunixin Meglumine ◽  
Chi Square Test ◽  
Pregnancy Recognition

The objective was to determine if administration of flunixin meglumine (FM) to heifers following insemination would increase pregnancy rate due to its inhibitory effect on prostaglandin F2� (PGF2�) synthesis. Fifty-two 15-month-old Holstein heifers were synchronized with single or double injections of PGF2� followed by an injection of gonadotropin-releasing hormone (GnRH) 48 h later and a timed artificial insemination at 12-14 h after injection of GnRH (Day 0). Heifers randomly assigned to the treatment group (FMG) were injected twice with FM (1.1 mg/kg BW; i.m.), given 12 h apart on the evening of Day 15 and the morning of Day 16. The control group (CG) was not treated. Pregnancy rates were defined as the percentage of heifers diagnosed pregnant by ultrasound at Days 29 and 65 after AI. Effects of treatment on pregnancy rates and pregnancy losses were analyzed by chi-square test and logistic regression analysis. Pregnancy rates in the heifers treated with FM were higher at Day 29 (76.9%; 20/26 [FMG] vs. 50%; 13/26 [CG]; P < 0.04) and tended to be higher at Day 65 (69.2%; 18/26 [FMG] vs. 46.2%; 12/26 [CG]; P < 0.09). Administration of FM two times at a critical stage leading up to pregnancy recognition, associated with corpus luteum maintenance, increased both early embryo survival and pregnancy rate via an additive antiluteolytic effect due to a delay in the luteolytic secretion of PGF2�; this provided conceptuses extra time to develop the capability to inhibit the luteolytic process.

scholarly journals Effect of dietary-induced changes in plasma insulin concentrations during the early post partum period on pregnancy rate in dairy cows

Reproduction ◽  
2009 ◽  
Vol 137 (4) ◽  
pp. 759-768 ◽  
Author(s):  
P C Garnsworthy ◽  
A A Fouladi-Nashta ◽  
G E Mann ◽  
K D Sinclair ◽  
R Webb
Keyword(s):  
Dairy Cows ◽  
Pregnancy Rate ◽  
Plasma Insulin ◽  
Post Partum ◽  
Ovarian Follicle ◽  
Developmental Competence ◽  
Cyclic Activity ◽  
Plasma Insulin Concentration ◽  
Mating Period ◽  
Ovarian Follicle Development

Dietary stimulation of insulin in post partum dairy cows has been found to enhance ovarian follicle development but to impair oocyte developmental competence. The objective of this study was to test the hypothesis that pregnancy rate would be improved by feeding a diet to stimulate higher insulin (H) until cows resumed ovarian cyclic activity after parturition, and then feeding a diet to lower insulin (L) during the mating period. Each diet was fed to 30 post partum dairy cows until their first rise in milk progesterone, when 15 cows in each group were transferred to the other diet (treatments HL and LH) and 15 cows in each group remained on their original diet (treatments HH and LL) until 120 days post partum. Treatments did not affect dry matter intake, milk yield and metabolisable energy balance. Plasma insulin concentration was elevated in cows fed on H compared with cows fed on L. Treatment did not affect days to first progesterone rise, first oestrus or first insemination. At 120 days post partum, 27% of cows on each of treatments HH, LL and LH were pregnant, but 60% of cows on treatment HL were pregnant (P=0.021). These findings support the concept that physiological relationships between insulin and the reproductive system vary according to stage of the reproductive cycle, and suggest that pregnancy rate can be enhanced by a two-diet strategy tailored to optimise responses before and after the first post partum ovulation.

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