scholarly journals 181COMPARISON OF THE PREGNANCY RATES AFTER SYNCHRONIZATION OF OVULATION USING GnRH AND PGF2± IN RECIPIENT DAIRY CATTLE

2004 ◽  
Vol 16 (2) ◽  
pp. 212 ◽  
Author(s):  
T. Nishisouzu ◽  
M. Sugawara ◽  
S. Aoki ◽  
K. Kishida ◽  
M. Moriyoshi ◽  
...  
Keyword(s):  
Dairy Cattle ◽  
Pregnancy Rate ◽  
Embryo Transfer ◽  
Fixed Time ◽  
Pregnancy Rates ◽  
Control Group ◽  
Corpora Lutea ◽  
Transfer Program ◽  
Chi Square ◽  
Follicle Diameter

Treatments with GnRH and PGF2α for synchronization of ovulation has resulted in acceptable pregnancy rates after fixed-time artificial insemination in dairy cows without estrus detection. The objective of the present study was to evaluate the practicability of ovulation synchronization (Ovsynch, Pursley JR et al. 1995 Theriogenology 44, 915–923) in dairy cattle using GnRH and PGF2α for the embryo transfer recipients. Dairy cattle (cows; n=100, heifers; n=88) were randomly allocated to one of two groups. The control group (cows; n=45, heifers; n=37) was composed of cows in natural estrus. The ovulation synchronization group (cows; n=55, heifers; n=51) was treated with an intramuscular injection of 100μg of GnRH at a random stage of the estrous cycle. Seven days later, the cattle received PGF2α (Cows; 25–30mg) or PGF2α analog (Heifers; 0.5mg) in order to regress the corpora lutea (CL). Forty-eight hours later, cows and heifers received a second injection of 100μg GnRH. Embryo transfer was carried out 7 days after the second injection of GnRH in the ovsynch group and 7 days after estrus in the control group. The cattle judged to have CL 17mm were classified as acceptable recipients. The size of the follicles and the CL were determined to be of estrus stage and embryo transfer by means of ultrasonography. The mean numbers of follicles and CL were analyzed by ANOVA, while pregnancy rates were analyzed by chi-square test. The results are presented in the Table. The proportion of cows and heifers determined to be acceptable embryo transfers was not different between the control group and the ovsynch group. There were no differences in the proportion of acceptable embryo transfers between the control group and the ovsynch group. Follicle diameter at the time of estrus in the control group (cows; 20.7±0.7mm, heifers; 16.8±0.5mm) were significantly larger than that of the ovsynch group (cows; 18.0±1.0mm, heifers; 14.7±0.2mm) (P<0.05). Although CL diameter at the time of embryo transfer in heifers showed no differences between the control group and the ovsynch group (25.0±1.0mm v. 22.8±1.5mm), The CL diameter of the control cow group was larger than that of the ovsynch group (29.8±0.7mm v. 26.1±1.0mm, P<0.05). However, no differences in pregnancy rate were seen between the control group and the ovsynch group. These results suggest that ovsynch can be effectively applied in an embryo transfer program for cattle. Table 1 Proportion of acceptable embryo transfer recipients and pregnancy rate in dairy cattle in the control ovsynch groups

10 INFLUENCE OF ADMINISTRATION OF HUMAN CHORIONIC GONADOTROPIN ON DAY 4 AFTER FIXED-TIME AI ON CORPUS LUTEUM SIZE, FUNCTION, AND PREGNANCY RATE IN BEEF COWS

2014 ◽  
Vol 26 (1) ◽  
pp. 119
Author(s):  
J. B. S. Borges ◽  
D. X. Thedy
Keyword(s):  
Corpus Luteum ◽  
Pregnancy Rate ◽  
Fixed Time ◽  
Beef Cows ◽  
Pregnancy Rates ◽  
Control Group ◽  
Chi Square ◽  
Prostaglandin F2a ◽  
Successful Establishment ◽  
Early Rise

Successful establishment of pregnancy in the cow depends on early rise of progesterone (P4) to improve embryo development. The present study was carried out to determine the corpus luteum (CL) function and pregnancy rate following the administration of 1.500 IU of hCG in suckled beef cows on Day 4 after fixed-time AI (FTAI). Crossbred Angus cows (n = 429), 40 to 70 days postpartum, were synchronized using 2 mg of oestradiol benzoate (EB) i.m. and an intravaginal progesterone-releasing device containing 1 g of P4 for 7 days. At device removal, prostaglandin F2a (150 mg of D-cloprostenol) was injected i.m.; 24 h later, 1 mg of EB was given and the FTAI were done 30 to 36 h after EB using semen of just 1 bull. Cows were assigned alternatively to receive 1.500 IU of hCG i.m. (n = 200) or 1 mL of saline i.m. (n = 229) on Day 4 after FTAI. Ovaries were examined by transrectal ultrasonography (n = 71) on Days 4 and 7 to detect the presence and to measure the area of CL. Blood samples were collected on Days 4, 7, 10, 14, and 30 post-oestrus to determine P4 concentration by RIA. Pregnancy diagnoses were done 30 days after FTAI. The effects of treatments on CL area and serum P4 levels were analysed by ANOVA (Proc GLM, SAS Institute Inc., Cary, NC, USA) and pregnancy rates compared by chi-square (Proc CATMOT, SAS). The induction of accessory CL determined on Day 7 was 44% in cows treated with hCG and not observed in the control group. The area of the CL on Day 7 was significantly higher (P < 0.01; 3.37 ± 2.56 v. 2.56 ± 0.22 cm2) in the hCG group. Despite the increase in CL size, the mean levels of P4 on Days 4, 7, 10, 14, and 30 post-AI indicated no difference (P > 0.05) in CL function between control and hCG-treated cows. On Day 30, pregnancy rates were not different (P = 0.08), at 46.7 and 55% for control and hCG-treated cows, respectively. In conclusion, administration of 1.500 IU of hCG on Day 4 post-FTAI did not improve pregnancy rate in suckled beef cows.

scholarly journals Influence of Injectable Progesterone on the Pregnancy Rate of Heifers Receiving Bovine Embryos

2020 ◽  
Vol 48 ◽  
Author(s):  
Caio Cezar Da Silva ◽  
Hélton Aparecido Garcia Gregianini ◽  
Jennifer Teodoro Ferreira Gregianini ◽  
José Antônio Dell’Aqua Junior ◽  
Jefferson Viana Alves Diniz ◽  
...  
Keyword(s):  
Pregnancy Rate ◽  
Embryo Transfer ◽  
Physiological State ◽  
Bos Indicus ◽  
Fixed Time ◽  
Treated Group ◽  
Pregnancy Rates ◽  
Control Group ◽  
Bovine Embryos

Background: In vitro embryo production (IVEP) allows the spread of superior animal genetics, but pregnancy rates show a high variability with this biotechnique. In the initial stage of pregnancy, progesterone plays a fundamental role in uterine preparation, acting on embryonic growth, implantation, and development. However, on the day of the IVEP transfer to the recipients, progesterone levels may be lower than that expected, influencing the uterine environment and, consequently, the pregnancy rate. Therefore, the objective of this study was to evaluate the pregnancy rate in heifers after the administration of injectable progesterone (P4) in the fixed-time embryo transfer (FTET) protocol.Materials, Methods & Results: The experiment was conducted inside a rural property near the city of Rio Branco, Acre, Brazil. The experimental group consisted of 232 animals, including 78 zebuine (Bos indicus) and 154 mixed (½ blood B. indicus and ½ blood B. taurus) animals, aged between 16 and 24 months, with a mean weight of 300 and 330 kg for zebuine and mixed animals, respectively. The selected animals were previously synchronized using the progesterone-estrogen-prostaglandin-estrogen protocol. Embryo transfer was performed on day 18 of the protocol, which was 9 days after the removal of intravaginal progesterone implant. On day 15 of the protocol, that is, 144 h (6 days) after the device removal, the animals were randomly distributed into two experimental groups: Control Group (CG; 0.5 mL of 0.9% saline solution, intramuscular) and Treated Group (P4G; 0.5 mL of injectable P4, 150 mg, intramuscular). Chi-square test was used for the statistical analysis of the pregnancy rate at a 5% probability. After 23 days of embryo transfer, pregnancy was diagnosed by ultrasonography. The general pregnancy rate, considering all groups (CG and P4G) and breeds included, was 55.17% (128/232). The pregnancy rates of the P4G and CG groups, regardless of breeds, were 55.08% (65/118) and 55.26% (63/114), respectively, with no statistical difference (P = 0.8344). Angus animals presented a similar pregnancy rate in the P4G and CG groups of 54.93% (39/71) and 57.83% (48/83), respectively. Furthermore, similar results were found for the Nellore breed, with no difference in pregnancy rate between the CG (55.81%, 24/43) and P4G (48.57%, 17/35) groups.Discussion: The strategy of using P4 to increase the pregnancy rate is very widespread in fixed-time artificial insemination (FTAI) protocols, although differences still exist. The literature presents zero or negative effects, as in this study, when exogenous P4 was used to increase endogenous P4 concentrations and, consequently, the pregnancy rate. However, some studies demonstrated the beneficial effects of increasing blood P4 concentrations, and that the increased fertility depends on the method and time of P4 supplementation and the animal’s physiological state. In this context, the fact that the injectable progesterone supplementation did not increase the pregnancy rate in this study is justified mainly by factors such as the animal category used (heifers), time of P4 supplementation (day 4 after ovulation), biotechnology used (FTET), and the heterogeneous characteristics related to phases of the estrous cycle of heifers. Supplementation with 150 mg of injectable long-acting progesterone intramuscularly did not interfere in the pregnancy rate of Angus and Nellore heifers receiving bovine embryos.

213 THE EFFECT OF eCG TREATMENT IN AN ESTRUS SYNCHRONIZATION PROTOCOL ON PREGNANCY RATES AFTER EMBRYO TRANSFER IN HOLSTEIN HEIFERS

2007 ◽  
Vol 19 (1) ◽  
pp. 223
Author(s):  
T. Okazaki ◽  
E. Sasaki ◽  
K. Hasegawa ◽  
T. Takani ◽  
S. Abe
Keyword(s):  
Embryo Transfer ◽  
Prostaglandin F2α ◽  
Estradiol Benzoate ◽  
Pregnancy Rates ◽  
Control Group ◽  
Corpora Lutea ◽  
Estrus Synchronization ◽  
Chi Square ◽  
Synchronization Protocol

Recent studies have shown that the presence of accessory or multiple corpora lutea (CL) and increased progesterone (P4) concentrations reduced early embryonic mortality in cattle. The objective of this study was to evaluate the effect of equine chorionic gonadotropin (eCG) treatment on the number of CL, the P4 concentrations, and pregnancy rates after embryo transfer (ET). Holstein heifers (n = 120) from 7 dairy farms received an intravaginal progesterone-releasing device (CIDR; InterAg, Hamilton, New Zealand) and 2 mg IM of estradiol benzoate (EB; Gynandol®; Sankyo, Tokyo, Japan) at random stages of the estrous cycle. After 7 to 9 days, CIDRs were removed and 15 mg of prostaglandin F2α (PG; Pronalgon®; Pfizer Japan, Nagoya, Japan) were administered, followed by 100 µg IM GnRH (Conceral®; Takeda Pharmaceutical Co., Ltd., Osaka, Japan) 2 days later (Day 0). The heifers were placed at random into 3 groups for eCG treatment. The eCG was not administered in a control group (n = 53); heifers in other 2 groups received 1000 IU eCG (Peamex®; Sankyo, Japan) IM at the time (0 h group, n = 37) or 48 h before (48 h group, n = 30) PG injection/CIDR removal. On Day 7, heifers were examined by ultrasonography (Aloka SSD500; Aloka, Tokyo, Japan) for number of CL; heifers with at least one functional CL received an in vivo-derived frozen–thawed embryo by direct transfer. At the same time, a blood sample was collected to determine P4 concentration. Pregnancy rates were determined on Days 30 and 60 by ultrasonography and rectal palpation, respectively. The data were analyzed by ANOVA and means were compared with Fisher's PLSD. Proportional data were analyzed by the chi-square test. P4 concentrations (mean ± SD) on Day 7 were 1.8 ± 1.0, 5.6 ± 3.3, and 2.2 ± 1.1 ng mL−1 for the control, 48 h, and 0 h groups, respectively (48 h vs. control and 0 h; P &lt; 0.001). The number of CL on Day 7 were 1.1 ± 0.4, 2.5 ± 1.4, and 1.8 ± 0.9 for the control, 48 h, and 0 h groups, respectively (control vs. 48 h and 0 h, and 48 h vs. 0 h; P &lt; 0.01). Pregnancy rates did not differ between 0 and 48 h groups but both were higher than in the control group (Table 1). Results suggest that the estrus synchronization protocol with administration of eCG at the time of CIDR removal or 48 h earlier significantly increased the number of CL and the P4 concentration, and improved pregnancy rates in Holstein heifers after ET. Table 1.Pregnancy rates of Holstein heifers synchronized with CIDR and PG and treated with eCG

189 PREGNANCY RATES IN HEAT-STRESSED DAIRY CATTLE RECEIVING ONE OR TWO IN VITRO-PRODUCED EMBRYOS IN A TIMED EMBRYO TRANSFER PROGRAM

2006 ◽  
Vol 18 (2) ◽  
pp. 202
Author(s):  
M. Franco ◽  
J. Block ◽  
F. D. Jousan ◽  
L. A. de Castro e Paula ◽  
A. M. Brad ◽  
...  
Keyword(s):  
Dairy Cattle ◽  
Pregnancy Rate ◽  
Embryo Transfer ◽  
Fetal Loss ◽  
Pregnancy Rates ◽  
Uterine Horn ◽  
Limiting Factor ◽  
Transfer Program ◽  
In Pregnancy

The objective was to determine whether transfer of two embryos would increase pregnancy rates in heat-stressed dairy recipients receiving an in vitro-produced embryo transferred into the uterine horn ipsilateral to the corpus luteum (CL). Such a treatment would increase the likelihood that the cow receives at least one embryo competent for sustained development. In addition, transfer of two embryos into the ipsilateral uterine horn is likely to increase the amounts of interferon-tau and other embryonic-signaling molecules in the uterus. A total of 32 virgin crossbreed heifers and 26 lactating crossbreed cows were used as timed embryo transfer recipients after being subjected to an ovulation synchronization protocol as follows: GnRH (100 �g) and insertion of previously used progesterone-containing CIDR on Day -10, prostaglandin F2� and CIDR removal on Day -3, and GnRH (100 �g) on Day 0 (day of anticipated ovulation). All recipients had a palpable CL on Day 6 and were randomly selected to receive one (n = 31 recipients) or two (n = 27) embryos on Day 7. At Day 64, the pregnancy rate tended to be higher (P = 0.07) for cows than for heifers. While not significant, heifers that received two embryos tended to have lower pregnancy rates than those that received a single embryo (20% vs. 41%); there was no difference in pregnancy rate in cows (50% for two embryos vs. 57% for one embryo). Pregnancy losses between Day 64 and Day 127 occurred in one group only cows receiving two embryos. In that group, pregnancy rate was 50% at Day 64 but 17% at Day 127. Overall, there was no difference in pregnancy rates at day 127 between cows and heifers, but recipients that received two embryos (17% for cows and 20% for heifers) had lower pregnancy rates (P < 0.03) than recipients that received one embryo (57% for cows and 41% for heifers). Only one animal, a cow, had twin fetuses at day 127. In conclusion, unilateral transfer of two embryos failed to improve pregnancy rates of dairy cattle exposed to heat stress. The fact that fetal loss occurred sooner for heifers than for cows points out the importance of uterine capacity as a limiting factor for maintenance of fetal development of two conceptuses. The suitability of timed embryo transfer was evident from the high pregnancy rates achieved with crossbreed females that received a single embryo. This work was supported by BARD Grant No. US-1551-14, USDA TSTAR Grant No. 2004-14135-14715, Grant No. 2001-12101-11318 from the USDA-IFAFS Program, and CAPES Grant No. 134202-1).

206 EFFECTS OF A COMBINATION OF A PRID, PGF2α AND eCG, ON ESTRUS SYNCHRONIZATION AND PREGNANCY RATE FOLLOWING EMBRYO TRANSFER IN HOLSTEIN HEIFERS

2007 ◽  
Vol 19 (1) ◽  
pp. 220 ◽  
Author(s):  
Y. Aoyagi ◽  
A. Ideta ◽  
M. Matsui ◽  
K. Hayama ◽  
M. Urakawa ◽  
...  
Keyword(s):  
Pregnancy Rate ◽  
Embryo Transfer ◽  
Plasma Concentrations ◽  
Pregnancy Rates ◽  
Bovine Embryo ◽  
Estrus Synchronization ◽  
Chi Square ◽  
End Of Treatment ◽  
Chi Square Analysis ◽  
Day Of Embryo Transfer

Successful bovine embryo transfer requires synchronization of luteolysis, estrus and ovulation. The objective of the present study was to evaluate the effect of a combination of a PRID, PGF2� and eCG, on estrus synchronization and pregnancy rate in recipient heifers. A PRID� (ASKA Pharmaceutical Co., Ltd., Tokyo, Japan) was inserted into the vagina at random days of the estrous cycle for 7 (n = 35) or 9 (n = 43) days. Two days before removal of the PRID, the heifers were injected with PGF2� IM (2 mL Resipron�-C containing 0.25 mg mL-1 cloprostenol; ASKA). About half of the heifers in each group received 250 IU eCG IM (Serotropin�; ASKA) at the time of PRID removal. Blood was collected several times from the start of treatment for 7 (n = 9) or 9 (n = 9) days and on the day of embryo transfer by jugular venipuncture; plasma was immediately separated and stored at -20�C until assayed for plasma concentrations of estradiol-17α (E2) and progesterone (P4). The E2 and P4 determinations were performed by enzyme immunoassay after extraction by diethyl ether. Pregnancy was determined by ultrasonography on Day 30 (Day 0 = estrus). The rates of successful standing estrus (no. in estrus/PRID inserted), embryo transfer (no. transferred/estrus), and pregnancy (no. pregnancy/transferred) were compared between groups. Data were analyzed by chi-square analysis or Fisher&apos;s PLSD test following ANOVA. Injection of eCG at the time of PRID removal had no significant effect on the rates of successful standing estrus, embryo transfer, or pregnancy (P &gt; 0.05). The proportion of heifers treated for 9 days that exhibited standing estrus (93&percnt;, 40/43) was significantly higher than the proportion of heifers treated for 7 days that exhibited standing estrus (66&percnt;, 23/35, P &lt; 0.01). Of the heifers that were treated for 9 days, the proportion of heifers exhibiting standing estrus within 2 days after the end of treatment was significantly higher (93&percnt;, 37/40) than for heifers that were treated for 7 days (65&percnt;, 15/23; P &lt; 0.01). Pregnancy rates of heifers treated for 9 days (84&percnt;, 32/38) and 7 days (81&percnt;, 17/21) were not significantly different. The E2 : P4 ratio normally increases during follicle growth and CL regression. The plasma E2 : P4 ratio between the time of injection of PGF2&alpha; and the time of PRID removal was significantly higher for heifers that were treated for 9 days than it was for heifers that were treated for 7 days (P &lt; 0.01). These results suggest that a combination of PRID treatment for 9 days and injection of PGF2&alpha; 2 days before PRID removal successfully synchronized estrus in recipient heifers and led to high pregnancy rates following embryo transfer.

289 EFFECTS OF YEAR PERIOD, TECHNICAL TEAM, AND BREED ON THE PREGNANCY RATES AFTER TRANSFER OF IVF BOVINE EMBRYOS IN THE SOUTHERN REGION OF RIO DE JANEIRO

2010 ◽  
Vol 22 (1) ◽  
pp. 301
Author(s):  
B. G. Moura ◽  
J. Almeida ◽  
F. L. Lima ◽  
G. Balbi ◽  
R. Calmerani ◽  
...  
Keyword(s):  
Beef Cattle ◽  
Dairy Cattle ◽  
Embryo Transfer ◽  
Pregnancy Rates ◽  
Chi Square ◽  
Chi Square Test ◽  
Few Data ◽  
Rectal Palpation ◽  
Fresh Embryos

The aim of the work was to study the effects of year period, technical team, breed, beef cattle and dairy cattle on the pregnancy rates in fresh embryos used in bovine transfer of IVF programs. The study was carried out at the fertilization laboratory In Vitro Nyltta Britto de Carvalho, in partnership with In Vitro Brazil, located at the Boa Vista farm, Barra do Pirai, during August 2007 to September 2008, seeking subsidies to improve the use of the technique in the field. During that period, aspirations and inovulations in 3 different periods I (August to December), II (January to April), and III (May to September) were carried out. The jobs were accomplished by 9 technical teams (A, B, C, D, E, F, G, H, and I) rendering services to the laboratory, by working with 2 beef breeds (Brahman and Nelore) and 3 dairy breeds (Gir, Girolando, and Holstein). The different breed receivers were synchronized, and in general, from 6 to 8 days after heat, they received embryo transfer, the cervical way, under low epidural anesthesia, where each female received 1 fresh embryo of IVF. All cows were submitted to gestation diagnosis by rectal palpation and ultrasonography, in general, 42 days after embryo transfer. The numbers of embryo transferred and pregnancy rates were submitted to the chi-square test, which presented significant differences (P < 0.05). There were pregnancy rates of 36.25%a (n = 960), 39.83%a (n = 1180), and 32.59%b (n = 919) in the I, II, and III periods, respectively. Among the 9 technical teams, there were verified pregnancy rates (%) of 33.51d (n = 1313), 30.30d (n = 330), 35.00cd (n = 405), 39.24cd (n = 1060), 59.25a (n = 7), 33.33d (n = 24), 53.57bc (n = 28), 43.31c (n = 157), and 58.33ab (n = 12) for A, B, C, D, E, F, G, H, and I teams, respectively. Among breeds there were rates (%) of 36.89ab (n = 412), 34.68b (n = 1286), 35.13ab (n = 74), 38.94a (n = 1140), and 37.80ab (n = 82) for Brahman, Nelore, Gir, Girolando, and Holstein, respectively. In the study, pregnancy rates (%) of 35.21b (n = 1698) in beef cattle and 38.65a (n = 1296) in dairy cattle were observed. The differences in pregnancy rates with respect to the evaluated factors, may be explained by individual, breed, and nutritional variations of the animals. There are few data in the literature with results on the embryo transfer use of IVF bovine under field conditions.

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.

151 EFFECT OF RECIPIENT CATEGORY ON PREGNANCY RATES ON A BOVINE EMBRYO TRANSFER PROGRAM IN PATAGONIA, ARGENTINA

2008 ◽  
Vol 20 (1) ◽  
pp. 155
Author(s):  
J. Villarreal ◽  
A. Garcia Guerra ◽  
G. M. Brogliatti
Keyword(s):  
Embryo Transfer ◽  
Pregnancy Rates ◽  
Point Of View ◽  
Bovine Embryo ◽  
Transfer Program ◽  
Chi Square ◽  
Lactating Cows ◽  
Significant Difference ◽  
Embryo Transfer Program ◽  
Condition Score

The fertility of the recipient is one of the more important factors conditioning the success of an embryo transfer (ET) program. Selection and management of recipients is a very important contributing factor to achieve high pregnancy rates (Stroud and Hasler 2006 Theriogenology 65, 65–76). From a reproductive point of view, a good recipient is a cow capable of receiving an embryo and taking it to term (Palma et al. 2001 Biotecnologia de la reproduccion, INTA). In beef and dairy cattle, recipients are categorized according to number of births, age, and condition score (Stroud and Hasler 2006). A retrospective analysis was done to confirm a relationship between recipient category, based on their physiologic and reproductive stage, and pregnancy rates. The analysis was done during January and February (2006–2007) based on data recovered from an embryo transfer program done in Chubut province (Patagonia) for the project ‘Polo Genetico Angus’ (Angus Association – Chubut government agreement). Two hundred and seven morulas and/or blastocysts, quality 1 or 2 frozen in 1.5 m ethylene glycol (IETS manual), were transferred randomly in 10 different farms. Embryos were thawed for 10 s at room temperature and 30 s in a water bath at 35°C and transferred by one single technician. Angus, Hereford, or its breeds were used as recipients. A reproductive exam was performed before embryo transfer and, based on it, recipients were classified into 4 categories: heifer (3–4 years old), lactating cow, weaned cow, and dry old cow (Table 1). The synchronization protocol used for recipients consisted of a single administration of D-cloprostenol and heat detection twice a day for 5 days. Data were analyzed by Cochran-Mantel-Haenszel test (chi-square). Results are shown in Table 1. There is a significant difference (P ≤ 0.05) in pregnancy rates among categories. Recipients with higher pregnancy rates were lactating cows and weaned cows 61.6% and 56.9%, respectively, compared to heifers, 45.3%; a lower pregnancy rate was founded in the dry old cows group. Dry cows were animals that failed to get pregnant during the last season. Heifers also were animals that failed the artificial insemination program. In both groups, the reduced fertility may explain their lower pregnancy rates. In conclusion, selection toward fertility of recipients is a very important factor to take into account to design a successful embryo transfer program. Table 1. Pregnancy rates for recipient categories in an ET program in Chubut (Patagonia), Argentina This research was supported by Centro Genetico Bovino Eolia.

scholarly journals Gestational losses after innovating with two embryos in a fixed-time embryo transfer program

2021 ◽  
Vol 14 (10) ◽  
Author(s):  
Carla Neves Barbosa ◽  
Felipe De Col ◽  
Juan Carlos Domínguez Fernández de Tejerina ◽  
Rodolfo Cassimiro de Araujo Berber
Keyword(s):  
Embryo Transfer ◽  
Birth Rate ◽  
Considerable Increase ◽  
Hormonal Treatment ◽  
Fixed Time ◽  
Estradiol Benzoate ◽  
Corpora Lutea ◽  
Transfer Program ◽  
Embryo Transfer Program ◽  
Group 1

The aim of this study was to quantify the pregnancy rate after implantation of two embryos after FTET protocols, as well as to monitor pregnancy losses until parturition, evaluating, mainly, if this strategy results in more number of animals born. Therefore, 423 multiparous recipients were selected, standardized in terms of body score, who had high-quality corpora lutea. Animals were randomly divided into two groups according to one or two embryos transferred (1 embryo = Control, n = 237; 2 embryos = Group 1, n = 186). All recipients received the same hormonal treatment, which consisted of administering, on Day 0, 2 mL of estradiol benzoate (Gonadiol, ZOETIS) + 1.9 g multidose 1st use progesterone implant (CIDR, ZOETIS); on Day 8 the implants were removed + injected 0.4 mL of estradiol cypionate (E.C.P, ZOETIS) + 1.5 mL of eCG (Novormon, ZOETIS) + 1 mL of dinoprost tromethamine (Lutalyse, ZOETIS). The animals were evaluated by ultrasonography at 30 and 60 days after embryo transfer, to diagnose the success rate and embryo losses during this period. Furthermore, information was collected on births, length of gestation, number of twin births, number of childbirth assistance and the weight of the calves. The results showed that Group 1 had better success than the Control, with higher conception rates at 30 days (68.3% vs. 53.2%, P<0.001) and at 60 days (62.9% vs. 52.3%; P<0 .05). The number of animals born was also higher for Group 1 (53.3% vs. 43.3%, P<0.01). The percentage of twins born in Group 1 was 17.9%, and the animals had lower weight compared to the Control (34.29 + 7.36 vs 37.63 + 5.73, P<0.05). The length of pregnancy and the number of assistances were similar between groups. In conclusion, the strategy adopted in this experiment suggests a considerable increase in the calf birth rate, but losses during pregnancy and their mechanisms need to be elucidated.

204 RELATIONSHIP BETWEEN RESPIRATORY ACTIVITY AND THE PREGNANCY RATE OF BISECTED BOVINE EMBRYOS IN VIVO

2007 ◽  
Vol 19 (1) ◽  
pp. 219 ◽  
Author(s):  
S. Moriyasu ◽  
H. Hirayama ◽  
K. Sawai ◽  
S. Kageyama ◽  
S. Aoyagi ◽  
...  
Keyword(s):  
Oxygen Consumption ◽  
Pregnancy Rate ◽  
Embryo Transfer ◽  
Respiratory Activity ◽  
Pregnancy Rates ◽  
Bovine Embryos ◽  
Chi Square ◽  
Important Indicator ◽  
Consumption Rates

Oxygen consumption is an important indicator of the metabolic activity of living cells, which may provide valuable information for evaluating embryo quality. We have found that the bovine embryos with high oxygen consumption possess stronger potential for further development. However, the relationship between respiratory activity and the pregnancy rate of embryos is still unclear. In this study, we investigated the respiration rates of bisected bovine embryos and the pregnancy rates of demi-embryos after embryo transfer. Compact morula-stage embryos were bisected evenly by micro glass needle. One hundred bisected embryos were incubated for 24 h in embryo culture medium (IVD101; Research Institute for the Functional Peptides, Yamagata, Japan) at 39�C under 5% CO2, 5% O2, 90% N2. After the incubation, demi-embryos were classified into 2 groups: blastocoel-formed (BC) and blastocoel-not-formed (CM) embryos. Oxygen consumption rates of demi-embryos were measured by scanning electrochemical microscopy (SECM; Hokuto Denko Corporation, Tokyo, Japan). Within 3 h after the measurement, 80 demi-embryos were transferred into recipient cows (one demi-embryo/one recipient) at 7–8 days after estrus. Recipient cows were diagnosed for pregnancy by ultrasonography approximately 40 days after estrus. Statistical difference was analyzed by Tukey's post-hoc test and chi-square test. A total of 27 recipient cows became pregnant; the pregnancy rates for cows with CM and BC demi-embryos were 40.6% (13/32) and 29.2% (14/48), respectively. Mean oxygen consumption rates (� 10-14 mol s-1) in pregnant and non-pregnant cows were 0.47 and 0.39 for CM demi-embryos and 0.63 and 0.52 for BC demi-embryos, respectively. Retrospective analysis showed that the respiratory activity of demi-embryos in the pregnant group was higher than those in the non-pregnant group. In particular, the pregnancy rates for demi-embryos with respiratory activity higher than 0.35 in CM and 0.40 in BC groups were 52.0% (13/25) and 35.9% (14/39), respectively. On the other hand, cows with demi-embryos having an oxygen consumption rate under 0.35 in CM (n = 7) and 0.40 in BC (n = 9) groups did not become pregnant. These results demonstrated that bovine demi-embryos with higher respiratory activity showed a high pregnancy rate after embryo transfer. It is generally known that the pregnancy rate after the transfer of bisected embryos is lower than that of whole embryos. The measurement of oxygen consumption by SECM procedures is a useful tool to assess the quality of pre-implantation embryos and may contribute to the improvement of the success rate for bisected embryo transfer.

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