• Journal of Embryo Transfer
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• v.5 no.2
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• pp.38-44
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• 1990

This study was carried out to produce superior dairy cattle by embryo transfer. Seven dairy cows were superovulated with divided injection of FSH 4Omg for 5 days started on day 9 to 14 of the estrus cycle and injection of PGF$_2$$\alpha$ 45mg on day 4 of FSH injection. Donor cows were flushed to collect embryos on day 7 or 8 of the estrus cycle. Fresh embryos collected were transferred to synchronized dairy recipients or frozen using glycerol 3 step method to he equilibrated. And 35 embryos which were frozen using glycerol 6 step method were imported from U.S.A. After glycerol dilution of frozen embryos was done by reverse density during freezing. frozen-thawed embryos were transferred to synchronized dairy or beef recipients. The results obtained were as follows; 1. Total of 24 embryos were collected from 7 donor cows flushed and transferable embryos were 18 (75.0%). 2. Among 24 embryos. morula, early blastocyst, blastocyst, expanded blastocyst and unfertilized ova were 3 (12.5%), 1 (4.2%), 10 (41.6%), 4 (16.7%) and 6 (25.0%), respectively. 3. Heat inducing rate after 1st and 2nd injections of PGF$_2$$\alpha$ in Holstein and beef cattle was 83.3% and 71.4% and 62.5% and 69.2%, respectively. 4. Among 56 recipients, 23 head were pregnant (41.1%). The pregnancy rate of fresh embryos was 50.0% (1/2 heads) and the pregnancy rate of frozen embryos which were frozen using glycerol 3 step and using glycerol 6 step imported from U.S.A. was 52.6%(l0/19 heads) and 34.3%(12/35 heads), respectively. 5. The pregnancy rate of blastocyst (60.0%) was higher than that of morula (39.0%), early blastocyst (25.0%) and expanded blastocyst (0%). 6. The pregnancy rate of grade I embryos (52.2%) was higher than that of grade 2 (34.6%) and grade 3 (28.6%). 7. The pregnancy rate according to synchrony of recipient with donor was higher in simultaneous recipient (55.0%) and +l2hrs' (53.8%) than -24hrs' (23.5%), -l2hrs' (20.0%) and +24hrs' (0%).

• Journal of Embryo Transfer
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• v.15 no.2
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• pp.175-180
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• 2000

The possible use of micromanipulative biopsy and PCR of the biopsied embryonic cells was tested to produce sexed bovine embryos in practical terms. By micromanipulation and PCR techniques, higher survival rate and accurate sexing of demi-embryos were btained. Bovine oocytes matured and fertilized in vitro were co-cultured with bovine oviductal epithelial cell (BOEC) monolayer in USU-6 medium supplemented with 15% FBS, and the embryos of 37% (327/885) were developed to blastocysts. Among 111 blastocysts produced by invitro, only 7 (6.3%) embryos were found unable to determine their sex, probably due to the loss of cells, since no PCR product was found from those cells. All the remaining 104 (93.7%) demi-embryos survived micromanipulation and demonstrated male-specific product or bovine-specific product alone suggesting that correct sexing of the sample. Forty-three point one percent(25/58) of manipulated and cryopreserved demi-embryos after thawing were survived. Final verification of the sexed embryos is necessary to make sure the same sex in fetus and newborn calf upon embryo transfer. The established sexing method on a large number of bovine embryos from previous and this study suggests that this a could be used practically in the field.

• Journal of Embryo Transfer
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• v.27 no.4
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• pp.193-203
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• 2012

The development of embryos reconstructed by nuclear transfer is dependent upon numerous factors including the type of recipient cell, method of enucleation, the type of donor cell, method of reconstruction, activation, the cell cycle stage of both the donor nucleus and the recipient cytoplasm and the method of culture of the reconstructed embryos. Many of these points which have been reviewed extensively elsewhere (Sun and Moor, 1995; Colman, 1999; Oback and Wells, 2002; Renard et al., 2002; Galli et al., 2003b), here we will concentrate on main area, the production of suitable cytoplast and nuclear donor, nuclear-cytoplasmic coordination, oocyte activation, culture of reconstructed embryos, and the effects that this may have on development.

• Journal of Embryo Transfer
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• v.15 no.1
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• pp.47-56
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• 2000

This study was carried out to improve a technique of embryo transfer for twin calves production in Hanwoo cattle. Blastocysts for the donor of embryo transfer were classified into three criteria by accessment of morphology; early blastocyst, blastocyst and expanded blastocyst. Tow embryos were introduced transcervically into utrerine horn either of Hanwoo or Holstein by ipsilaterally or contralaterally to the corpus luteum. Thiry-six out of 57 recipients cows were inseminated by artificially on the next day of estrus, and followed by transfer of embryos into contralaterally. The pregnance rates of recipients following transfer of bovine embryos of day 7, 8 and 9 was 43.5, 18.2 and 8.3%, respectively. These results appeared that these was a significant (P<0.05) difference between on day-7 embryos and day-9 embryos, but not between on day-8 and day-9 embryos. Although there was not significant(P<0.05) difference in the pregnancy rates between the blastocysts(11/25, 44%) and expanded blastocysts(2/19, 10.5%) and between the blastocysts and early blastocysts(2/13, 15.4%), the embryos at blastocyst stage are more suitable than others for obtaining higher rate of pregnancy. There was no significant difference on pregnancy of the embryos transferred prior to presence(6/21, 29%) or absence (9/36, 25%) of artificial insemination. On pregnancy of Holstein, 2(15.4%) out of 13 recipients were pregnant in heifer. Similar Pregnancy rates were obtained between 1∼2 parities and 3∼4 parities by 30% (6/20) and 27.3%(3/11), respectively. Taken together, there was not significant difference in pregnancy rate due to small number of recipients used for this experiment. Both of Hanwoo and Holstein introduced the embryos by contralsterally to the corpus luteum were slightly higher pregnancy rate compare to by ipsilaterally (12/41, 29.3% vs, 3/16, 18.8%). The ratio of production of twin and single calves in Holstein was 20% (9/45) and 2.2% (1/45), respectively. However, in Hanwoo cows both of production of twin and single were similar as 8%. This result suggests that Holstein as recipients was superior to Hanwoo cows for production of twin calves. Out of all 15 pregnant, 12(80%) were produced a total of 22 normal calves in which the others composed of abnormal, as judging as 2(13.3%) for abortion and 1(6.6%) for stillbirth during the pregnant period.

• Journal of Embryo Transfer
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• v.24 no.1
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• pp.71-76
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• 2009

It is not easy for porcine embryos produced by in vitro systems to develop into blastocysts with high quality. To solve this problem, many researchers have developed novel culture methods. However, the formation of blastocysts with high quality is still low. In this study, we aimed to produce piglet following transfer of in vitro produced early embryos ($2{\sim}4$ cell stage embryos) or morula and blastocyst. The $2{\sim}4$ cell stage embryos were transferred to five estrus-synchronized recipients (200 embryos per recipient). One of the five sows farrowed three piglets, which contain two live piglets and one dead piglet, 114 days after embryo transfer. However, two recipients transferred with morula and blastocysts did not farrow. Microsatellite analysis confirmed that the genomic DNA of two live piglets were not genetically identical to that of the recipient. These results indicate that it is possible to obtain piglets by transfer of early embryos produced by in vitro production (IVP) systems.

• Journal of Embryo Transfer
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• v.12 no.2
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• pp.151-159
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• 1997

In vitro fertilization(IVF) derived morula and blastocyst embryos were bisected by a simple method and cultured in vitro without zona pellucida And also bisected embryos were frozen-thawed and cultured in vitro) to evaluate the survival rate. The results obtained were as follows : The average number of grade I or II immature follicular oocytes recovered by slicing method per ovary was 11.9 from 142 ovaries. Following in vitro fertilization, the rates of cleavage and in vitro development to morula and blatocyst were 61.7 and 32.2% respectively. The successful bisection rate of IVE embryos was 67.51%, and the embryos of blastocyst stage were bisected successfully at significantly(P

• Korean Journal of Animal Reproduction
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• v.7 no.1
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• pp.19-23
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• 1983

Present studies were conducted to investigate the developmental stage and the location of embryos in the reproductive tract at various times after ovulation, the morphologically normal after thawing of embryos preserved in liquid nitrogen, and the survival after transferring frozen-thawed embryos. The results obtained were as follows: 1. Embryo stage and location in the reproductive tract after hCG administration. For the investigation of embryo stage and location in the reproductive tract after ovulation, rabbits were laparotomized at 24, 40, 48, 72 and 120 hrs post hCG injection, simultaneously with mating. the oviducts and uteri were flushed out with PBS medium containing 50% rabbit serum, respectively. 1) Most of embryos was remained in the oviduct within 48 hrs, with the lapse of time, embryos were started to move to uterus and shifted in uterus at 72 hrs after hCG injection. 2) The representatives of embryos stage collected at 24, 40, 48, 72 and 120 hrs were 1-cell(60.4%), 8-cell to early morula (52.3, 39.3%), late blastocyst (95.5%) stages, respectively. 2. Morphological normality and survival of the frozen-thawed embryos. For the evalution of the quality and viability on the frozen-thawed embryos, immediately after thawing, embryos were assessed by morphologically normal under a dissecting microscope, and a further test of frozen-thawed embryos was made by transferring the morphologically normal embryos to the uteri of recipient rabbit induced pseudopregnancy by the injection of hCG at the time of hCG injection in donor rabbits. 1) The propotions of embryos which a, pp.ared morphologically normal was higher when 8-cell (85.7%) and morula(90.5%) were used for freezing than when 4-cell (66.7%) and blastocyst (75.8%) were used. 2) Preganacies were observed at Day 15 after transfer of frozen-thawed 8-cell (7/13), morula (19/42) and blastocyst (3/19) but not after transfer of embryos at 4-cell stage.

• Korean Journal of Veterinary Research
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• v.36 no.4
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• pp.919-927
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• 1996

In the last few years, methods for in vitro culture of early embryo stages from oocytes matured and fertilized in vitro using suitable cell culture systems have been established. But the factors affecting pregnancy rates following transfer of bovine embryos produced in vitro were not evaluated enough. So this study was performed to investigate the effects of quality and stage of embryos, parity and Corpus Luteum quality of recipients on pregnancy rates following non-surgical transfer of bovine embryos produced in vitro. Oocytes aspirated from small antral follicles of ovaries obtained at a local slaughter house were matured, fertilized with frozen-thawed semen and co-cultured for 6-7 days by utilizing co-culture system with bovine oviduct epithelial cell in vitro. After co-culture, embryos were transfered to recipients on day 7 (estrus=day 0). Recipients were monitored by ultrasonic scanning method or observation for estrus and rectal palpation after 50 days from transfer. The results of this study are follows. 1. Of the 70 recipients, 70%(49 of 70) had not showed estrus sign between day 0 and day 50, but 22.9%(16 of 70) was diagnosed not pregnant. Therefore the overall pregnancy rate of this study was 47.1%(33 of 70). 2. The pregnancy rate of recipients transfered with excellent(66.7%) and good(54.5%) embryos were higher than that of recipients transfered with fair embryos(15.8%) (p<0.05). 3. The pregnancy rate of recipients transfered with morula, compacted morula, blastocyst and expanded blastocysts were 46.2, 55.0, 62.5 and 50.0%, respectively. 4. The pregnancy rates of recipients transfered to heifer and cow were 54.5 and 55.2%, respectively. 5. The pregnancy rates of recipients with CL score I, II(66.7, 63.6%) were higher than those of recipients with CL score III (10%), (p<0.05). Success of transfer of embryos produced in vitro depends on many variables. The important factors identified in this study were the quality of embryos and the CL score of recipient animals after non-surgical transfer of embryos matured, fertilized and cultured in vitro.

• Asian-Australasian Journal of Animal Sciences
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• v.14 no.9
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• pp.1342-1351
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• 2001

Over the years, the embryo transfer industry has grown from the simple collection & transfer of embryos into an advanced field of embryo biotechnology. Currently a large demand exists for bovine oocytes and early embryos in both research and commercial settings. Bovine embryos can now be produced in-vitro. Primary oocytes collected from antral follicles of abattoir - obtained ovaries can be induced to undergo the maturation process. In-vitor maturation system, however must ensure that the resulting oocyte is capable of undergoing normal fertilization and yields a zygote competent of developing to term after embryo transfer. Sperm preparation for IVF has improved with the use of heparine. The use of co-culture system has proved beneficial in circumventing the developmental block in IVM/IVF bovine embryos.

• Journal of Embryo Transfer
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• v.19 no.3
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• pp.209-218
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• 2004

To investigate the feasibility of embryo transfer technology to promote productivity of cattle, 36 cows(18 Holstein, 18 Hanwoo) were superovulated. Fresh embryos were transferred to 25 recipients(14 Holstein, 11 Hanwoo), whereas frozen embryos were transferred to 17 recipients(10 Holstein, 7 Hanwoo). Two embryos were transferred at a time to 13 recipients(9 Holstein, 4 Hanwoo) to produce twin calves. 1. 75.0％ of donor cattle were reacted to hormonal treatment far superovulation. 2. The rate of embryo recovery by non-surgical method for Holstein and Hanwoo was 90.4 and 95.8％ in comparison with numbers of corpus luteum. 3. Of all the ova collected non-surgically, the rate of viable blastocyst was 66.4％ and the rate of transferrable blastocysts was 48.6％. 4. The rate of embryo collection by one-catheter method was 75.0％. 5. The rate of pregnancy/delivery following embryo transfer with fresh embryos was 60.0％. 6. The rate of pregnancy/delivery following embryo transfer with frozen embryos was 35.3％. 7. In embryo transfer to produce twin calves, the rate of pregnancy/delivery was 28.6％ with fresh embryos and 16.7％ with frozen embryos.