• 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 Embryo Transfer
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• v.13 no.1
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• pp.61-67
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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 affacting pregnancy rate after embryo transfer by condition of recipients were as follows ; 1. The pregnancy rate by age and parity of recipients showed high in 5~8 and over 12 years old(72.7~73.9%), and 3rd~4th parity(82.1%) for fresh embryos(P<0.05). The pregnancy rate did not differ by age and parity of recipients in frozen embryos. The pregnancy rate of frozen embryos tended to be similar to that of fresh embryos(38.5% and 25.0~36.7%). 2. The number of observation for normal estrus cycles of recipients did not differ In pregnancy rate between one and 2 times in fresh embryos(64.9%, 69.8%). The pregnancy rate by transferred frozen embryos showed significantly higher after 2 times of observation(P<0.05, 16.3%, 37.5%). The pregnancy rate by days open did not differ between fresh and frozen embryos. But the pregnancy rate was slightly higher in 12 months and 6 months of days open for fresh and frozen embryos, respectively(70.1~71.1% and 24.5%, respectively). 3. The pregnancy rate of transferred fresh and frozen embryos into right and left side of uterine horn did not differ(62.1% : 65.9% 25.0% : 24.3%, respectively). The pregnancy rate by the grade of CL was not different in fresh embryos, but the pregnancy rate was significantly higher in the grade A than B for frozen embryos(P<0.01, 43.2%, 16.2%).

• Journal of Animal Science and Technology
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• v.65 no.4
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• pp.779-791
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• 2023

This study aimed to assess the effects of embryonic developmental stage, quality grade, and fresh or frozen/thawed conditions on the pregnancy rate and sex ratio of live offspring in Hanwoo (Bos taurus coreanae) cows. The quality and developmental stage of in vivo-derived (IVD) transferred embryos were evaluated using the standard criteria of the International Embryo Technology Society. The recipient cows were synchronized using conventional (estradiol benzoate and progesterone) protocols before embryo transfer. Embryos were transferred to 297 cows, and pregnancy was monitored for 60-70 days after embryo transfer. The pregnancy rates of fresh and frozen/thawed embryos were 56.90% and 52.49%, respectively. Pregnancy rates varied according to embryo quality (56.18% for grade 1 vs. 36.67% for grade 2). Pregnancy rates also varied by developmental stage and cryopreservation (67.86% vs. 63.49% for stage 4-1, 64.00% vs. 54.72% for 5-1, and 50.00% vs. 47.83% for 6-1, in fresh embryos vs. frozen/thawed embryos, respectively). For stage 7-1, the pregnancy rates were 72.73% for fresh embryos and 20.00% for frozen/thawed embryos. In 66 fresh embryos, the sex ratio of live offspring was 5:5, whereas it was 4(female):6(male) for frozen/thawed embryos among the 95 frozen/thawed embryos. The miscarriage rate was approximately 3% higher for frozen/thawed embryos than for fresh embryos (18.1% for fresh vs. 21.1% for frozen). Seasonal fertility rates were 33.3% in spring, 55.67% in summer, 52.8% in autumn, 60.0% in winter. The following male-to-female ratios were observed in different seasons: 6.7:3.3 in spring, 4.0:6.0 in summer, 5.5:4.5 in autumn, and 3.3:6.7 in winter. The current data revealed no significant differences in pregnancy rates between fresh and frozen/thawed IVD embryos. However, there was a lower pregnancy rate with advanced-stage frozen/thawed embryos (stage 7-1). The current study provides comprehensive results for the better optimization of embryo transfer in Hanwoo cattle to obtain the desired fertility rate, pregnancy rate, and sex ratio of calves. These results provide important insights into the factors that influence the viability and success of IVD embryo transfer in Hanwoo cows and may have practical applications for improving breeding programs and reducing production costs.

• Journal of Embryo Transfer
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• v.13 no.1
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• pp.69-76
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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 were transferred into a toral of 301 recipients. The results obtained in studies on the factors affecting pregnancy rate after embryo transfer by condition of transfer time were as follows ; 1. The pregnancy rate by the seasons of transferred fresh and frozen embryos were not different, but the pregnancy rate was slightly higher in summer(80.8%). 2. The pregnancy rate by the days of embryo transfer after estrus were not different when fresh embryos were transferred, but the pregnancy rate was highest at 8 days when frozen embryos were transferred(P<0.01, 40.0%). 3. The pregnancy rate at estrus synchronization was remarkably higher with PGF$_2$$\alpha$ treated than natural (P<0.05, 70.4%, 43.4%). 4. The pragnancy rate by the degree of estrus synchronization was best when the estrus was synchronized in both fresh and frozen embryos (83.3% and 29.7%, respectively), but the pregnancy rate was not different among $\pm$2 days. But the pregnancy rate of frozen embryos were slightly higher when the recipients exhibited estrus earlier than donors.

• 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 Plant Biotechnology
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• v.36 no.2
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• pp.184-192
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• 2009

The influences of pretreatment medium, the addition of fresh medium, and the size of culture plate on the production of embryos were investigated in isolated microspore culture of hot pepper (Capsicum annuum L.). Among the media used for heat shock pretreatment ($32{\pm}1{^{\circ}C}$), high frequency embryo production was obtained when the sucrosestarvation medium A was used. On the other hand, neither 0.37 M mannitol solution nor NLNS medium supplemented with sucrose was not efficient for embryo production. The addition of culture medium to pretreatment media considerably decreased the embryo production even though embryo development proceeded further. The embryo production was not improved by the addition of fresh medium after 2 or 3 weeks from starting culture. Increase in the size of the culture plate from $3.5{\times}1.0$ cm to $6.0{\times}1.5$ cm improved embryo quality. These results will provide valuable information for developing an efficient microspore culture system of hot pepper for high frequency embryo production.

• 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.

• Journal of Embryo Transfer
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• v.17 no.2
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• pp.91-100
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• 2002

The experiment was divided into two phases. In phase-I fresh embryos were transferred and in Phase-II frozen embryos were transferred. Embryos were collected by using Dulbecco's phosphate buffered saline. In phase-I total of 65 ova were collected out of 107 ovulation in 18 goats. Recovery of ova was 60.74％, of which 51 (78.46％) was fertilized. Sixteen embryos were transferred to 10 recipient goats and kidding was observed in 6 goats, that produced 10 kids. Thus, 62.50％ embryo survival and 60％ kidding were achieved in phase-I. In phase-II of the experiment, 17 regular cyclic Black Bengal goats were used. The main purpose was to study the viability of caprine embryos after cryopreservation. In this phase the embryos were collected and frozen using Bio-cool freezers. A two step addition of cryoprotectants (5％ glycerol and 10％ glycerol) and three-step dilution of cryoprotectants with 1mole (M) sucrose was used. Embryos were preserved for 10 to 45 days. Out of 27 embryos preserved, 18 were recovered after freezing and thawing (37$^{\circ}C$ water bath) with 33.33％ embryonic loss. Seventeen frozen and thawed embryos were transferred in 9 recipient goats, out of which kidding was observed in 6 goats and 7 kids were produced, giving a 66.66％ kidding and embryo survival of 41.17％. The technique utilized for fresh and frozen embryo transfer can be successfully utilized to produce goats of superior genetic merits. The protocol used for addition of cryoprotectant, freezing, thawing and dilution was found suitable for caprine embryo freezing.

• Journal of Animal Reproduction and Biotechnology
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• v.38 no.2
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• pp.84-88
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• 2023

Because multiple ovulation embryo transfer (MOET) in cattle includes several benefits such as wide spreading of genetically superior offspring for long distance, this biotechnological method has been widely applied to Hanwoo. When the recipients are not stayed close after embryo recovery from donor, the embryos are moved to other farms via several vehicles (car, train, and airplane). However, air travel induces lesser oxygen level, increased vibration, lower air pressure, higher noise, and increased exposure of cosmic radiation to living things than ground level. It was still unknown that fresh embryos obtained from multiple ovulation of Hanwoo could maintain their fertility after being transported via air plane, the present case report introduced a clinical case of MOET in Hanwoo after shipping fresh embryos via air transportation. The donor was multi-ovulated via follicle-stimulating hormone series of injection, which was followed by a gonadotrophin-releasing hormone injection and artificial insemination twice. The embryos were recovered by the uterine flushing, packed in ministraws, transported to recipients for 6 h including 1 h air flight, and then transferred to the synchronized recipients. During pregnancy diagnosis of early gestation period, 5 of 7 recipients (71.4%) presented no heat signs and showed fetal sacs with fluid under transrectal ultrasonography. After normal gestation period, all recipients naturally delivered healthy calves (male n = 2 and female n = 3) without abortion, stillbirth, and premature birth. The present case report indicated that transportation of fresh embryos for MOET via domestic flight in Korea did not affect to their fertility.

• Journal of Embryo Transfer
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• v.14 no.3
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• pp.171-176
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• 1999

This study was carried out to investigate the effect of co-culture system(bovine oviduct epithelial cells; BOEC) and defined culture system (modified TALP ; mTALP) on the conception of embryos transferred, and pregnancy and twin birth rates after transfer of fresh or frozen-thawed bovine blastocysts produced in vitro were also evaluated. Oocytes from the slaughterhouse ovaries were matured and fertilized using general protocol. The results obtained were as the following. The pregnancy rate after transfer was higher in co-culture group than in mTALP group, but was not signficantly different, and there is no difference between fresh embryo group and frozen-thawed embryo group in conception rate. The conception rate was not different whether 3∼4 blastocysts or 2 blatocysts transferred into a recipient, but the production rate of twin calves was significantly higher (p<0.05) when 3∼4 embryos transferred. The average birth weight of twin calves(24.38kg) was numerically, but not significantly lighter than that of single calves(26.68kg).