17 INFLUENCE OF DIFFERENT CONCENTRATIONS OF PROGESTERONE DURING FIXED-TIME ARTIFICIAL INSEMINATION PROTOCOLS ON OVULATION AND PREGNANCY RATES IN NELORE HEIFERS

2008 ◽  
Vol 20 (1) ◽  
pp. 89
Author(s):  
M. F. Pegorer ◽  
R. L. Ereno ◽  
C. M. Barros
Keyword(s):  
Artificial Insemination ◽  
Bos Indicus ◽  
Prostaglandin F2α ◽  
Fixed Time ◽  
Estradiol Benzoate ◽  
Pregnancy Rates ◽  
High Concentration ◽  
Serum Progesterone ◽  
Significant Difference ◽  
Intravaginal Device

Previous reports indicate that a high concentration of serum progesterone (P4) decreases LH pulse frequency (Burke et al. 1996 Anim. Reprod. Sci. 45, 13–28) and, consequently, follicular growth. This may reduce the efficiency of fixed-time artificial insemination (FTAI) protocols that utilize P4 in Bos indicus heifers (Marques et al. 2005 Acta Sci. Vet.). The objective of the present work was to evaluate the influence of different P4 concentrations on the ovulation and pregnancy rates of zebu heifers subjected to hormonal protocols for FTAI. Four hormonal protocols with different P4 concentrations were used to induce synchronization of ovulation in Nelore (Bos indicus) heifers (n = 292). Before the beginning of the treatments, the animals were subjected to ovary evaluations by ultrasonography (Aloka SSD 500, 5-MHz probe; Aloka, Tokyo, Japan) twice in an interval of 10 days. Only heifers with a corpus luteum (CL) in at least one of the ultrasonographic evaluations were utilized. At a random stage of the estrous cycle, the selected heifers received an intravaginal progesterone-releasing device containing 0.558 g of P4 [Triu�, Biogenesis, Buenos Aires, Argentina; Treatment 1 (T1); n = 76], or 1 g of P4 [Cronipress�, Biogenesis; Treatment 2 (T2); n = 70], or 0.558 g of P4 and prostaglandin F2α (PGF2α) [150 �g d-cloprostenol, IM, Croniben�, Biogenesis; Treatment 3 (T3), n = 75], or 1 g of P4 and PGF2α [Treatment 4 (T4), n = 71]. At the time of intravaginal device insertion (Day 0 = D0), all animals received 2 mg of estradiol benzoate (EB, Bioestrogen�, IM, Biogenesis), and PGF2α was administered only in animals from groups T3 and T4. Eight days later (D8), PGF2α (0.150 g d-cloprostenol) was administered to all heifers and the P4 source was removed. Twenty-four h after removal of the intravaginal device, the heifers were treated with EB (1 mg, IM), and 30 to 36 h later all animals were fixed-time inseminated (FTAI, D10), without estrus detection. In a subset of heifers from each group (T1 = 28; T2 = 34; T3 = 33; T4 = 31), ovarian ultrasonography was performed on D9 (at 8:00 A.M.) and D11 (at 14:00 P.M.) in order to determine ovulation rate after each treatment. The data were analyzed by logistic regression (GENPROC, SAS; SAS Institute, Inc., Cary, NC, USA). Ovulation rates after treatments T1, T2, T3, and T4, were, respectively, 71.4% (20/28), 76.5% (26/34), 84.9% (28/33), and 70.9% (22/31), and there was no significant difference among groups (P > 0.05). Pregnancy rates, ascertained by ultrasonography 40 days after AI, were 30.2% (23/76), 25.7% (18/70), 33.3% (25/75), and 28.2% (20/71), respectively, for T1, T2, T3, and T4, and likewise there was no significant difference among groups (P > 0.05). It is concluded that reduction of progesterone concentration in the intravaginal device (1 g v. 0.558 g) associated or not with administration of PGF2α at the beginning of treatments did not significantly influence ovulation and pregnancy rates in Nelore heifers submitted to a FTAI protocol. Additional experiments are underway to confirm or not the present results. This work was supported by FAPESP (Brazil) and BIOGENESIS (Argentina).

Effect of recombinant bovine somatotropin on pregnancy rates of Nellore cows resynchronized with the use of new DIB and third use, and inseminated at fixed-time

2015 ◽  
Vol 4 (1) ◽  
pp. 356-362
Author(s):  
Josemara Silva Santos ◽  
Tania Cavalcante ◽  
Francisca Elda Ferreira Dias ◽  
Domenica Palomaris Mariano de Souza ◽  
Alencariano J.S. Falcão ◽  
...  
Keyword(s):  
Artificial Insemination ◽  
Linear Models ◽  
Plasma Concentrations ◽  
Fixed Time ◽  
Estradiol Benzoate ◽  
Pregnancy Rates ◽  
Recombinant Bovine Somatotropin ◽  
Equine Chorionic Gonadotropin ◽  
Rectal Palpation ◽  
Intravaginal Device

The objective of the experiment was to evaluate the effects of recombinant bovine somatropin (rbST), and the reuse of the progesterone (P4) releasing devices in resynchronization, on the pregnancy rates of Nellore cows submitted to fixed-time artificial insemination. A group of 123 multiparae Nellore cows, was submitted to a resynchronization protocol: on day 0 a Bovine Intravaginal Device (DIB® ) with 1,0g of P4 was implanted, associated with intramuscular administration of 2,0mg of estradiol benzoate (IM); on day 8 DIB was removed; and 1,0mg of estradiol cypionate, 0,15mg of prostaglandin F2? and 300 UI of equine chorionic gonadotropin were administered; on day 10, fixed-time artificial insemination was conducted (FTAI). The cows were randomized into G1 (n=12) – without rbST / with used Bovine Intravaginal Device, G2 (n=50) – without rbST / with new DIB, G3 (n=11) - with rbST / with used DIB and G4 (n=50) – with rbST/ with new DIB. rbST was introduced on the eighth day of the protocol. Sixty days after TAI, pregnancy diagnoses were conducted, via rectal palpation. Blood samples were taken on day 0, 8 and 10 of the protocol, in order to assess P4 plasma concentrations. Pregnancy rates were statistically evaluated through Generalized Linear Models Theory and their significance was tested with Analysis of Deviance. Pregnancy rates were 58%, 40%, 81% and 48% for G1, G2, G3 and G4, respectively, with significant statistical difference for G3. Plasma concentrations of P4 were not statistically different among groups, or collections. In view of the results obtained, we concluded that the administration of rbST in association with P4 DIB, used for the third time, improves pregnancy rates. Estrus resynchronization and re-insemination positively impacted pregnancy rates.

scholarly journals 23 PREGNANCY RATE IN NELORE COWS AFTER TEMPORARY CALF REMOVAL, AND USE OF HORMONAL PROTOCOLS WITH eCG

2005 ◽  
Vol 17 (2) ◽  
pp. 161
Author(s):  
V. Pinheiro ◽  
A. Souza ◽  
R. Ereno ◽  
C. Barros
Keyword(s):  
Artificial Insemination ◽  
Buenos Aires ◽  
Post Partum ◽  
Fixed Time ◽  
Estradiol Benzoate ◽  
Pregnancy Rates ◽  
Calf Removal ◽  
Exogenous Progesterone ◽  
Intravaginal Device ◽  
Hormonal Treatments

Both temporary calf removal (TCR) and administration of eCG are potentially useful to improve pregnancy rates in animals treated with fixed-time artificial insemination (FTAI) protocols. In the present work, two experiments were performed to compare the efficiency of eCG and/or TCR in FTAI protocols, with or without exogenous progesterone. In experiment 1, lactating Nelore cows (40 to 70 days post-partum, n = 220) were allocated to two Groups. At a random stage of the estrous cycle (Day 0), animals from Group GPE (GnRH/PGF2α/Estradiol)/eCG were treated with GnRH (50 mg lecireline, i.m.; Gestran Plus®; Tecnopec, Sao Paulo, Brazil). Seven days later (Day 7) they received PGF2α (150 mg D-cloprostenol, i.m.; Prolise®, Tecnopec) and eCG (300 UI, i.m.; Novormon®, Syntex). On Day 8 estradiol benzoate (EB, 1 mg, Estrogin®, Tecnopec) was administered, and 30–36 h later the animals were inseminated (FTAI). In Group DIB (bovine intravaginal device)/eCG an intravaginal progesterone-releasing device (1.0 g, DIB®, Syntex, Buenos Aires, Agrentina; Day 0) was inserted into the vagina of cows and EB (2.5 mg, i.m.) was given in parallel. Eight days later (Day 8), eGC (300 UI, i.m.) and D-cloprostenol (150 mg) were administered. Then the DIB was removed. Twenty-four hour after DIB removal, cows were treated with EB (1.0 mg, i.m.), and 30–36 h later the animals were inseminated (FTAI). Ultrasonographic evaluation of ovaries was performed in all experiments 10 days before and at the beginning of the treatments or TCR, in order to detect the presence of CL. Cows from Group DIB/eCG showed higher pregnancy rates than those from Group GPE/eCG (58%, 72/124 vs. 39.5%, 38/96, respectively, P < 0.01). Furthermore, only in Group GPE/eCG were pregnancy rates higher in animals with CL (47.6%, 20/42) when compared to those without CL (33%, 18/54, P < 0.05). In a second experiment, a possibly beneficial effect of TCR on GPE/eCG protocol was tested in lactating Nelore cows (40 to 70 days postpartum, n = 140). Animals of Group GPE/eCG (control) were treated as described above, whereas calves were removed for 48 h from cows in Group RTB/GPE/eCG prior to hormonal treatments. Lactating Nelore cows having their calves removed showed a significant increase in pregnancy rates compared to those without TCR (51.2%, 34/66 v. 28.4%, 21/74, respectively, P < 0.01), in both situations: animals with CL (54.8%, 17/31 v. 33.3%, 11/33, respectively, RTB/GPE/eCG v. GPE/eCG) or without CL (48.5%, 17/35 v. 24.3%, 10/41, respectively, RTB/GPE/eCG v. GPE/eCG). In conclusion, these results indicate that addition of eCG to the GPE protocol was not efficient enough to produce comparable results to those obtained with DIB/eCG protocol. However, calf removal before the GPE/eCG treatment increased pregnancy rates in cycling or anestrous (without CL) lactating Nelore cows.

Effects of postpartum energy intake on pregnancy rates in beef cattle subjected to GnRH- or CIDR-based timed artificial insemination protocols

2008 ◽  
Vol 88 (3) ◽  
pp. 439-447 ◽  
Author(s):  
J. J. Wichtel ◽  
E. Charmley ◽  
G. F. Richardson ◽  
J. L. Duynisveld ◽  
R. Lofstedt
Keyword(s):  
Beef Cattle ◽  
Energy Intake ◽  
Artificial Insemination ◽  
Body Condition Score ◽  
Post Partum ◽  
Fixed Time ◽  
Estradiol Benzoate ◽  
Pregnancy Rates ◽  
Estradiol Treatment ◽  
Serum Progesterone

The objectives were to determine the effects of three levels of postpartum metabolisable energy (ME) intake on pregnancy rates in beef cattle subjected to either GnRH-based (OVS) or progestin-based (CIDR) protocols for fixed time artificial insemination (TAI). Hereford cross cows were assigned to ME and TAI treatments (within ME) on the basis of parity and predicted calving date. The postpartum grass-silage-based diet was formulated to provide either Low (93 MJ d-1), Medium (103 MJ d-1) or High (120 MJ d-1)] ME from calving (January to February) to turnout (May 25). Lactating cows [n = 175, 5.7 ± 1.1 mean (± SD) body condition score at calving] were subjected to their assigned TAI protocol; OVS [i.m. treatments of GnRH (100 μg) on day 0, PGF2α (25 mg) on day 7, a second GnRH on day 9 and TAI 16 to 18 h later], or CIDR [i.m. treatment with 1 mg estradiol benzoate and 100 mg progesterone concurrent with CIDR (1.9 g progesterone) insertion on day 0, PGF2α treatment at CIDR removal on day 7, a second estradiol treatment on day 8 and TAI 28 to 30 h later). Cows were 60 ± 13 d post-partum at the time of insemination. Lower ME intakes reduced (P < 0.05) maternal body weight and calf weight gain, but ME intake did not affect (P > 0.05) the proportion cycling (113/175 = 65%, based on serum progesterone concentrations on days -5 and -14), ovulation following TAI, or the TAI pregnancy rates (based on ultrasonography). Timed insemination pregnancy rates were greater for CIDR- than OVS-treatment (63 vs. 45%, respectively, P < 0.05), regardless of ME intake. Key words: Beef cow, estrus synchronization, Ovsynch, CIDR, energy intake, reproduction, calf gains

13 USE OF EQUINE CHORIONIC GONADOTROPIN OR FOLLICLE-STIMULATING HORMONE-LUTEINIZING HORMONE AT IMPLANT REMOVAL OR AT FIXED-TIME ARTIFICIAL INSEMINATION TIME IN PREGNANCY RATE OF SUCKLED NELLORE COWS

2015 ◽  
Vol 27 (1) ◽  
pp. 99
Keyword(s):  
Pregnancy Rate ◽  
Artificial Insemination ◽  
Bos Indicus ◽  
Prostaglandin F2α ◽  
Fixed Time ◽  
Pregnancy Rates ◽  
Implant Removal ◽  
Transrectal Ultrasonography ◽  
Follicular Growth ◽  
The Difference

Use of eCG as an inducer of follicular growth has improved the efficacy of fixed-time artificial insemination (FTAI) protocols and increased the ovulatory responses and pregnancy rates in beef cattle with low body condition scores (BCS) or are recently postpartum and anestrous. However, there are other gonadotropins such as FSH in different commercial applications (Pluset® – FSH : LH proportion ~50.0%) that could be potentially used to increase follicular growth but with controversial results. The goal of this trial was to evaluate the effects of replacing eCG with FSH/LH in two moments on the pregnancy rates (PR) of lactating Bos indicus cows raised in native grassland at Pantanal. The cows were subjected to a synchronization-of-ovulation protocol and FTAI based on progesterone, oestradiol benzoate (EB), and prostaglandin F2α. On Day 0, Nellore multiparous cows (n = 352) at 42 days postpartum with BCS = 4.9 (1–9) were evaluated by transrectal ultrasonography and received progesterone implant (DIB 1.0 g of progesterone) plus 2 mg of EB IM. Devices were removed and prostaglandin F2α was injected on Day 8 with 1 mg of EB. At the time of implant removal, the animals received T1 – 1 mL of saline solution IM (control; n = 80); T2 – 300 IU IM of eCG (Novormon®; ECG; n = 92); T3 – 40 IU IM of FSH/LH (Pluset®; Pluset; n = 98). The T4-group cows received 40 IU IM of FSH/LH (Pluset®) at FTAI time (Pluset-FTAI; n = 82); cows were timed-AI on Day 10 (44–48 h after implant removal) and evaluated by transrectal ultrasonography to measure the preovulatory follicle (POF) at FTAI and to estimate the pregnancy rate on Day 45. The effects of the treatment, sire, and BCS on pregnancy rate were evaluated using PROC GLIMMIX (SAS Institute Inc., Cary, NC). Because there was no difference between BCS, sire, and PR, they were removed from model. Pregnancy rate was not different between the treatment groups (control: 38.70%; ECG: 51.08%; Pluset: 45.91%, and Pluset-FTAI: 39.02%; P > 0.05), but the difference was found in POF, higher in ECG group – 13.53 mm compared with others (Pluset: 12.79 mm; control: 11.73 mm, and Pluset-FTAI: 12.01 mm; P < 0.05). Although PR was not different between treatments, the data are in agreement with the size of POF, where the largest POF are associated with tendency of higher pregnancy rates in ECG group. In conclusion, commercial FSH solution does not provide increases in PR, and eCG increases the preovulatory follicles in Nellore cows with a low-moderate BCS submitted to a progesterone-based FTAI protocol with EB at implant removal.

Estrous synchronization and fertility of cross-bred dairy cows using prostaglandin F2α and gonadotropin releasing hormone

2021 ◽  
pp. 171-175
Author(s):  
Abubakr O. Ismail ◽  
◽  
Erneo B. Ochi ◽  
Ambrose S. Jubara ◽  
Bakri Ahmed A/Rahim ◽  
...  
Keyword(s):  
Dairy Cows ◽  
Artificial Insemination ◽  
Prostaglandin F2α ◽  
Fixed Time ◽  
Gonadotropin Releasing Hormone ◽  
Pregnancy Rates ◽  
Releasing Hormone ◽  
Treatment Groups ◽  
Estrous Synchronization ◽  
Descriptive Statistical Analysis

A comparative hormonal study of prostaglandin, gonadotropin releasing hormone and their combination was conducted on 30 randomly selected cross-bred dairy cows of SEMEX project for artificial insemination in Hillat Kuku, Khartoum North, Sudan. The study attempts to determine the response of the animals to hormonal induction and synchronization of estrous as well as fertility following fixed time artificial insemination. Three treatment groups of 10 cows each were undertaken. Groups 1, 2 and 3 involved administration of prostaglandin F2α (PGF2α), gonadotropin releasing hormone (GnRH) and a combination of PGF2α + GnRH, respectively. Descriptive statistical analysis was performed. The results revealed that all the three protocols induced and synchronized estrous were almost synchronous in all the treated groups. However, protocol 3 revealed a significantly (p<0.05) better result of 70% pregnancy rate compared to other two protocols that equally provided 50% pregnancy rates. The study resolves that protocol 3 be highly recommended to change the mindset of farmers about the spread of reproductive technology in Sudan. Protocols 1 and 2 provided acceptable pregnancy rates that can be enhanced with the improvement of management.

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.

39 EFFECT OF TIME OF FIXED-TIME AI ON PREGNANCY RATES IN ZEBU CROSS-BRED BEEF HEIFERS TREATED WITH PROGESTERONE RELEASING DEVICES AND ESTRADIOL CYPIONATE

2010 ◽  
Vol 22 (1) ◽  
pp. 177 ◽  
Author(s):  
M. Ramos ◽  
L. Cutaia ◽  
P. Chesta ◽  
G. A. Bó
Keyword(s):  
Bos Taurus ◽  
Body Condition Score ◽  
Bos Indicus ◽  
Fixed Time ◽  
Estradiol Benzoate ◽  
Pregnancy Rates ◽  
Beef Heifers ◽  
Treatment Groups ◽  
Condition Score ◽  
To Receive

Two experiments were designed to evaluate the effect of the timing of fixed-time AI (FTAI) in relation to the removal of an intravaginal progesterone-releasing device (1 g of progesterone, DIB, Syntex SA, Buenos Aires, Argentina) on pregnancy rates in Bos indicus × Bos taurus cross-bred heifers. In experiment 1, 285 Bonsmara × zebu cross-bred heifers, between 18 and 24 months of age and with a body condition score (BCS) between 3.0 and 3.5 (1-5 scale) were used. On the day of initiation of treatment (Day 0), the heifers’ ovaries were palpated (92% of them had a CL) and they received a new DIB plus 2 mg of estradiol benzoate (EB; Syntex SA) and 250 μg of cloprostenol (Ciclase DL, Syntex SA). On Day 8, DIB devices were removed and all heifers received 250 μg of Ciclase plus 0.5 mg of estradiol cypionate (ECP; Cipiosyn, Syntex SA). At that time the heifers were randomly divided to receive FTAI between 48 to 49 h, 53 to 54 h, or 58 to 59 h after DIB removal. The heifers underwent FTAI with semen from 4 bulls by 2 inseminators. In experiment 2, 260 heifers from the same group as those used in experiment 1 (87% with a CL) were treated exactly as those in experiment 1, except that previously used DIB was inserted on Day 0. Pregnancy diagnosis was performed 30 days post-fixed-time AI by ultrasonography. The data were analyzed by logistic regression, taking into account the effect of time of FTAI, semen, and inseminator on pregnancy rates. In experiment 1, pregnancy rates were lower (P = 0.04) in the heifers undergoing FTAI between 48 and 49 h after DIB removal (46/95, 48.4%) than those undergoing FTAI 53 to 54 h (61/99, 61.6%) or 58 to 60 h (57/91, 62.6%) after DIB removal. However, no differences in pregnancy rates were found (P = 0.72) in experiment 2 between the 3 treatment groups, with 39/91 (42.9%) for the 48 to 49 h group, 45/89 (50.6%) for the 53 to 54 h group, and 35/89 (43.8%) for the 58 to 59 h group. There was no effect of the semen or inseminator (P > 0.2) in either experiment. We conclude that when Bos indicus × Bos taurus beef heifers are synchronized with new DIB devices and ECP, higher pregnancy rates are obtained in heifers undergoing FTAI late (between 53 to 60 h after DIB removal) than in those undergoing FTAI early (48 to 49 h after DIB removal). However, time of insemination does not apparently affect pregnancy rates when Bos indicus × Bos taurus beef heifers are synchronized with previously used DIB devices and ECP.

scholarly journals 180EFFECT OF TIME OF ECG TREATMENT ON PREGNANCY RATES IN BOS INDICUS×BOS TAURUS RECIPIENTS SYNCHRONIZED WITH PROGESTERONE VAGINAL DEVICES AND TRANSFERRED WITHOUT ESTRUS DETECTION

2004 ◽  
Vol 16 (2) ◽  
pp. 212
Author(s):  
L.F. Nasser ◽  
E.L. Reis ◽  
A.M. Oliveira ◽  
G.A. Bo ◽  
P.S. Baruselli
Keyword(s):  
Bos Taurus ◽  
Bos Indicus ◽  
Fixed Time ◽  
Estradiol Benzoate ◽  
Pregnancy Rates ◽  
Bovine Embryo ◽  
Treatment Groups ◽  
Estrus Detection ◽  
Treatment Interaction

It has been shown recently that treatments with progesterone (P4)-releasing devices combined with estradiol benzoate (EB) plus P4 on Day 0, eCG and PGF on Day 5 and a second application of EB one day after device removal (Day 9) can be used successfully to transfer bovine embryos at a self-appointed time, without the necessity of estrus detection. Although the treatment solved one of the major problems in recipient management, estrus detection, it requires handling the recipients at least five times for treatments and embryo transfer. An experiment was designed to evaluate whether reducing one day of handling, by the administration of eCG and PGF at the time of removal of the P4 device (Day 8), results in comparable pregnancy rates than giving eCG on Day 5. A secondary objective was to determine the effect of injectable P4 at the time of device insertion plus EB treatment. Crossbred Bos taurus×Bos indicus beef heifers (n=301) were randomly assigned to 4 treatment groups in a 2 by 2 factorial design. All Heifers received a P4 device (DIB, Syntex, Argentina) plus 2mg EB i.m. (Syntex) at unknown stages of the estrous cycle (Day 0), with or without 50mg of P4 given i.m. at the same time. Heifers were further subdivided to receive PGF (0.150mg d-cloprostenol, Prolise, Tecnopec, Sao Paulo, Brazil) and 400IU of eCG (Novormon, Syntex) i.m. on Days 5 or 8. In all heifers, DIB devices were removed on Day 8 and 1 mg EB was administered i.m. on Day 9. Day 10 was arbitrarily considered as the day of estrus. On Day 17, heifers were bled for plasma P4 concentrations and examined by ultrasonography to determine the number of CL and their diameter. Heifers that had &gt;1 CL or a single CL with diameter ≥18mm received an in vitro-produced (IVP) embryo by nonsurgical transfer performed by the same veterinarian. Pregnancy rates were determined by ultrasonography 30 days later. The effects of Day of eCG administration (Day 5 or Day 8), P4 of treatment (E2 or E2+P4) and the day-by-P4 treatment interaction on the numbers of CL and plasma P4 were analyzed by ANOVA, and the proportion of recipients selected and pregnant were analyzed using non-parametric tests (NPAR1WAY, SAS). There was no significant effect of P4 treatment or the P4-by-day of eCG interaction in any of the parameters evaluated. However, there was a significant effect of day of eCG administration on plasma P4 concentrations (Day 5=2.4±0.3 v. Day 8=1.7±0.2; P=0.03) and the number of CL (Day 5=1.4±0.1 v. Day 8=1.1±0.0; P=0.02) on Day 17. Furthermore, the proportion of recipients pregnant/treated tended (P=0.1) to be higher in heifers in the Day 5 Group (71/151, 47.0%) than in those in the Day 8 Group (61/150, 40.7%). Although delaying the eCG and PGF administration from Day 5 to Day 8 saves one trip through the chute for treatments, it resulted in lower plasma P4 concentrations and tended to decrease pregnancy rates in bovine embryo recipients synchronized with DIB devices and EB and transferred at a fixed time. Furthermore, the administration of injectable P4 at the time of DIB insertion did not affect pregnancy rates.

150 EXAMINATION OF ESTRUS SYNCHRONIZATION USING A PRID® + PROSTAGLANDIN F2α AND PREGNANCY RATE AFTER ARTIFICIAL INSEMINATION FOLLOWING TRANSFER OF IN VITRO-PRODUCED EMBRYOS IN REPEAT-BREEDING COWS

2008 ◽  
Vol 20 (1) ◽  
pp. 155
Author(s):  
M. Urakawa ◽  
A. Ideta ◽  
K. Hayama ◽  
K. Tsuchiya ◽  
Y. Aoyagi
Keyword(s):  
Pregnancy Rate ◽  
Rate Control ◽  
Prostaglandin F2α ◽  
Estradiol Benzoate ◽  
Pregnancy Rates ◽  
Uterine Horn ◽  
Estrus Synchronization ◽  
Significant Difference ◽  
Clinical Disorders

Repeat-breeding Holstein cows (RBCs), i.e. cows that have undergone three or more AIs, have reduced pregnancy rates. The present study aimed to determine whether application of a combination of a PRID� (ASKA Pharmaceutical Co., Inc., Tokyo, Japan) + prostaglandin F2α (PGF2α) for estrus synchronization and AI + embryo transfer (ET) would improve pregnancy rates in RBCs. All RBCs selected showed a normal interval between the previous insemination and estrus, and were free of clinical disorders. The RBCs (n = 107) received a PRID for 9 days with a capsule containing 10 mg of estradiol benzoate, 0.5 mg IM of cloprostenol (PGF2α, Resipron�-C; ASKA, Japan) at 2 days before PRID removal. The cows were inseminated with frozen–thawed semen from a bull at 0 to 12 h after onset of estrus. Seven days after AI, single in vitro-produced embryos were transferred to the same RBCs. Pregnancy was diagnosed by palpation per rectum at e60 days post-insemination. Exp. 1 estimated the response to estrus synchronization treatment (n = 107). The factors examined were lactation number (mean � SD: 2.3 � 1.5, range: 1–6), insemination number (5.2 � 2.2, range: 3–13), and the interval from calving to next AI (275.9 � 97.6 days, range: 93–650 days). Exp. 2 compared the pregnancy rate in control RBCs (n = 161) and PRID-treated RBCs (n = 100). The factors examined included lactation number (2.5 � 1.6, range: 1–12), insemination number (6.0 � 2.5, range: 3–19), the interval from calving to next AI (288.0 � 102.1 days, range: 102–797 days), and whether the ET was into the uterine horn ipsilateral or contralateral to the CL in a total of 261 RBCs. Data were analyzed using logistic regression. The results for Exp. 1: 103 cows (96.3%) were confirmed to be in estrus (2.0 � 0.3 days after PRID removal). Although the frequency of estrus was affected by the lactation number (P = 0.014) and the interval from calving to the first AI (P = 0.005), the AI number did not have an affect (P = 0.624). Exp. 2: PRID synchronization had no effect on pregnancy rate (control: 37.3%, 60/161; and PRID-treated: 40.0%, 40/100). For the RBCs, the pregnancy rate was not affected by lactation number (P = 0.093), AI number (P = 0.694), or the interval from calving to next AI (P = 0.762). No significant difference (P = 0.428) in pregnancy rate was observed in cows when the embryos were transferred into the uterine horn contralateral to the CL (43.5%, 20/46), compared to those embryos transferred into the uterus horn ipsilateral to the CL (37.2%, 80/215). In conclusion, our findings suggest that the pregnancy rate may be improved by considering lactation number and the interval from calving to the next AI of RBCs in estrus synchronization using a combination of PRID + PGF2α and AI + ET.

Sign in / Sign up

Export Citation Format

Share Document