• Korean Journal of Animal Reproduction
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• v.11 no.2
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• pp.122-126
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• 1987

This study was carried out to investigate the effects of the glycerol equilibration methods and embryo grades before freezing on the survival rate after thawing in mouse embryos. The results obtained from this study were as follows: 1. The number of embryos of grade I(Excellent), II(Good) and III(Fair) before freezing in this study was 97(27.4%), 160(45.2%) and 97(27.4%), respectively. 2. The average survival rate of frozen-thawed embryos in 3 and 5 steps glycerol equilibration was 66.7% and 64.1%, and the rate of transfererable embryos after culture was 68.9% and 69.0%, respectively. 3. Out of embryo grade I and II before freezing, the transferable rate after thawing was 75.2% and 48.1%, respectively, and grade I embryos before freezing was higher transferable rate than that of grade II.

• Journal of Embryo Transfer
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• v.13 no.1
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• pp.53-60
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• 1998

This study was carried out to establish an effective system for embryo transfer techniques by analyzing several factors affecting in-vivo embryo transfer in Korean cattle. Embryos produced in-vivo were transferred into a total of 301 recipients. The results obtained in studies on the factors affecting pregnancy rate after embryo transfer by condition of embryos were as follow ; 1. The pregnancy rate of 301 recipients was 45.2% and higher with fresh embryos than with frozen embryos(63.5% : 21.4%, P<0.01). Embryos superovurated by FSH-P had slightly greater than by SUPER-OV in pragnancy rate, athough these were no difference between two treatments. 2. The pregnancy rates of transferred morulae and blastocysts showed no difference between fresh and frozen embryos(63.5% : 63~6% ; 20.0% : 25.8%). However, the pregnancy rates by quality of flesh and frozen embryos were significantly different(P<0~05). The pregnancy rates were outstandingly high in the grade A, B of fresh embryos(59.0~66.4%), and in the grade A of frozen embryos(43.6%). 3. The number of transferred embryos showed no difference in pregnancy rate, but when frozen embryos transferred, the pregnancy rate was slightly higher with two embryos than that with one embryo.

• Journal of Veterinary Clinics
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• v.5 no.1
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• pp.1-7
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• 1988

An observational study was conducted to evaluate the effect of anterior pituitary gonadtropin on super-ovulation in donors, embryo quality, development stage of embryo, transfer location, corpus luteum quality of recipient, ease of transfer and induced versus natural estrus on pregnancy rates. The data were collected from 451 non-surgical transfers of fresh and frozen bovine embryos. 1. The average number of CL, formed in ovaries which were stimulated with follicular stimulating hormone, and/or APG, were 11. 1${\pm}$1.21, 12.3${\pm}$1.84, respectively. The numbers of embryos recovered were 8.2${\pm}$1.35, 8.7${\pm}$ 1.39, and the numbers of transferable embryos were 6.4${\pm}$0.98. 6.6${\pm}$1.01. respectively. 2 There was no effect of spontaneous versus prostaglandin-induced estrus of recipients on pregnany rates of either fresh (61.5% vs. 59.5%) or previously frozen(54.5% vs. 58.5%) embryos. 3. There were significant differences(p<0.05) in pregnancy rates for embryo grade 1(63.6%), grade 2 (45.4%) and grade 3 (30.4％) in fresh group and for grade-1 (60.5%), grade-2 (47.8%) and grade-3 (18.1%) in previously frozen embryos. 4. The recipients transfered with embryo morulae were found to have a lower (p<0.05) pregnancy rates than those transfered with embryos of blastocyst in be th fresh and previously frozen embryos. 5. There was no significant difference between transfer locations in pregnancy rates using both fresh and frozen embryos. 6. Attempts to select recipients for high pregnancy rates on the basis of corpus luteum (CL) quality were performed. CL were classified into 3 quality grades, on the basis of size and prominence. Quality grades 1 and 2 group had higher (p<0.05) pregnancy rates than grade-3 group using both fresh and frozen embryos. 7 Ease of transfer was ranked to a scale of one to three on the basis of increasing difficulty (time required). Transfers ranted as ease score 1 and 2 had significantly higher (P<0.05) pregnancy pregnancy rates (45.8%, 66.6%) than ease score 3 (27.7%, 31.8%) using both fresh and frozen embryos respectively.

• Journal of Embryo Transfer
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• v.26 no.1
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• pp.33-36
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• 2011

The objective of this work was to determine the effect of corpus luteum (CL) grade on pregnancy rate after embryo transfer in Korean cattle and we found that CL development was linked to pregnancy rate. The in vivo derived blastocyst-stage embryos were transferred to 15 recipients synchronized in the estrus cycles. Based on size and palpable characteristics, CLs were categorized into three grade. The grade three CL is not to be identified by rectal palpation. The pregnancy rates tended to increase with the increase in CL size of recipients. In grade one, two, and three, the pregnancy rates were 62.5%, 50.0%, and 0%, respectively. This result suggests that pregnancy rates after embryo transfer might be affected by the CL status of recipients.

• Clinical and Experimental Reproductive Medicine
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• v.51 no.1
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• pp.69-74
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• 2024

Objective: The purpose of this study was to identify factors associated with twin pregnancy following day 3 double embryo transfer (DET). Methods: This retrospective cohort study incorporated data from 16,972 day 3 DET cycles. The participants were women aged between 18 and 45 years who underwent in vitro fertilization with intracytoplasmic sperm injection (IVF/ICSI) at My Duc Assisted Reproduction Technique Unit (IVFMD), My Duc Hospital, located in Ho Chi Minh City, Vietnam. Results: Of the 16,972 day 3 DET cycles investigated, 8,812 (51.9%) resulted in pregnancy. Of these, 6,108 cycles led to clinical pregnancy, with 1,543 (25.3% of clinical pregnancies) being twin pregnancies. Factors associated with twin pregnancy included age under 35 years (odds ratio [OR], 1.5; 95% confidence interval [CI], 1.32 to 1.71; p<0.001) and cycles involving the transfer of at least one grade I embryo. Relative to the transfer of two grade III embryos, the risk of twin pregnancy was significantly elevated following the transfer of two grade I embryos (OR, 1.40; 95% CI, 1.16 to 1.69; p<0.001) or a combination of one grade I and one grade II embryo (OR, 1.27; 95% CI, 1.05 to 1.55; p=0.001). Conclusion: By analyzing a large number of IVF/ICSI cycles, we identified several predictors of twin pregnancy. These findings can assist medical professionals in tailoring treatment strategies for couples with infertility.

• Journal of Embryo Transfer
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• v.23 no.4
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• pp.291-298
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• 2008

We separately cultured follicular oocytes collected from individual ovaries of slaughtered Korean native cows and examined both the embryonic development rate and pregnancy rate after embryo transplantation according to the meat yield and quality grades of the source beef carcass. Oocytes from meat yield grade B cows exhibited a higher fertilization rate and embryonic developmental rate to the eight-cell stage than oocytes from grade A or C animals (p<0.05), but there was no significant difference in rate of development to the blastocyst stage among meat yield grades A, Band C. The oocyte cleavage rate and development rate to the eight-cell stage from meat quality grade 3 cattle was higher than grades 1++, 1+, 1 and 2 (p<0.05). Embryos derived from grade animals displayed a development rate to the blastocyst stage of 19.4%, which was also higher than all other meat quality grades (p<0.05). Transplantation of in vitro-cultured oocytes from meat yield grade A ovaries led to a higher pregnancy rate (64.2%) than in vitro-cultured oocytes from meat yield grade B ovaries (56.5%), but there was no significant difference between the two groups in pregnancy or abortion rates. In conclusion, embryonic development rate and pregnancy rate has a close relation to meat quality grades of the source beef carcass, this results is to give information for the Korean native cows improvement of breed.

• Journal of Embryo Transfer
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• v.17 no.1
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• pp.23-32
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• 2002

To establish an effective in vivo Hanwoo embryo production system, several factors including types of FSH analogue, FSH treatment day, grade of Corpus Luteum were examined. Among FSH analogues. Super-OV was shown to have lower effect on transferable embryo production (P<0.01). Regarding the day of FSH treatment, there were significant difference in estrus status of donors(P<0.1), fertilization rate, and transferable and freezable embryo production(P<0.05). Finally, embryo production was significantly(P<0.01) higher in grade A (8.06 ∼9.49) Corpus Luteum which showed more than 6 on the left or right ovary than in grade B, C and D(2.93∼6.28).

• Journal of Embryo Transfer
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• v.17 no.1
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• pp.33-44
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• 2002

These studies were carried out to establish an effective in vivo embryo transfer methods in Hanwoo by analyzing several factors that influence this process. In an embryo transfer, recipients with grade A corpus luteum of the right ovary and that of grade B of the left one showed a higher pregnancy rate(p<0.1) than others. The pregnancy rates of frozen embryos were significantly lower(P<0.01) than those of fresh ones; the former resulting in 35% and the latter resulting in 56.2%. Transfer of embryos according to the estrus cycle(6.0 ∼ 9.0 days) did not show a significant difference in pregnancy rate with fresh embryos recording 45.4 ∼65.7% and frozen ones recording 22.0 ∼ 50.0%. According to the status of corpus luteum and embryo freezing or not, the pregnancy rate was higher on grade A corpus luteum with 40.8 ∼67.9% than B and C which ranged from 25.0∼56.0%. The results of embryo transfer according to the development stage and grade of embryos showed that regardless of the embryo's grade. transfer of morula recorded an average pregnancy rate of 46.3%. This results higher than the transfer of blastocyst which was 34.1%.

• Journal of Embryo Transfer
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• v.8 no.2
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• pp.105-109
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• 1993

This study was carried out to propagate Korean native cattle using beef recipients by embryo transfer. Seven Korean native cattle donors were superovulated with FSH 32mg and Embryos collected from donors were frozen and preserved in National Animal Breeding Institute. Frozen-thawed embryos were transferred to synchronized 40 beef recipients nonsurgically in Daekwanryeong Branch of National Animal Breeding Institute. The results obtained were as follows : 1. Total ova and transferable embryos per donor were 11.4 and 11.1 from 7 donors, respectively. 2. Among 40 recipients transferred with frozen-thawed embryos, 20 were pregnant(50.0%). 3. The pregnancy rate according to time from embryo thawing to transfer was higher when transferred within 3 hours than after 3 hours(57.6% vs. 14.3%). 4. The cow recipients showed slightly higher pregnancy rate than the heifer(53.3% vs. 48.0%). 5. Two grade embryos showed higher pregnancy rate than 1 grade(66.7% vs. 45.2%).

• Journal of Embryo Transfer
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• v.1 no.1
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• pp.76-80
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• 1986

This study was carried out to investigate the inte actions between recipients and embryos to compare pregnancy rates in bovine embryo transfer, such as synchrony and stage of embryos, synchrony and quality of embryos, synchrony and side of uterine horn, and preservation time and stage of embryos. Fifty-two embryos were transferred by surgically to 42 Holstein heifers, 3 Holstein cows and 7 Korean native heifers from Feb., 1985 to June, 1986. The results were as follows: 1. In the trial of interactions between synchrony and embryo stage, recipients synchronired from- hours to + 12 hours in synchrony and embryos from morulac stage to advanced blastoctyst stages showed reason able pregnancy rate. 2. Excellant (A) and good (B) grade embryos showed good pregnancy rate, 81.8% and 73.3% respectively, but fair (C) grade embryos showed poor, 25% only at the same boundary of recipient synchrony. 3. More recipients had corpus luteum on the right ovary than the left, and also had better pregnancy rate (26/32 vs 13/20,81.3% vs 65%). 4. A good pregnancy rates (over 60%) were obtained with the embryo transferred 17hrs after flush at room temperature or field condition in culture medium.