• Journal of Embryo Transfer
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• v.15 no.1
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• pp.57-65
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• 2000

The objective of this study was to apply the multiple ovulation and embryo transfer (MOET) program practically in dairy herds. Forty five superior Holstein cows ranked in 5% according to Type-Production Index(TPI) in Korea were selected as donors. The donors were superovulated with pFSH and the embryos collected from donors were frozen and preserved. The preserved embryos and frozen Holstein embryo imported from foreign country were thawed and transferred to recipients. The results obtained were as follows; 1. The total number of ova and freezable embryos collected per donor was 6.5 and 2.8, respectively. 2. The freezable embryos were obtained more(p<0.05) when the body condition score (BCS) of donors was in range of 2.50∼3.25(4.1) than in range of 3.50∼4.00(1.9), while the total number of ova was not changed. 3. The season affected on the collected number of freezable embryos(6.1 in winter, 4.5 in fall, 1.1∼1.5 in spring and summer, P<0.05), and the total number of obtained ova were more in winter than in other seasons(P<0.05). 4. Embryos were transferred to 343 recipients and 152 cows were confirmed pregnant(44.3%). 5. The higher pregnancy was obtained (P<0.05) when embryos were transferred in summer(53.3%) than in fall(36.0%), while the pregnancy rate was not affected by the origin and developmental stage of embryos, and the parity, BCS and estrus induction of recipients. From these results, the pregnancy rate was considered to be acceptable for the embryo transfer with domestic or imported Holstein embryos, however embryo production from superior Holstein donors was unsatisfactory for application of MOET scheme.

• Journal of Embryo Transfer
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• v.30 no.4
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• pp.345-350
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• 2015

In the last 10 years, porcine somatic cell nuclear transfer to generate transgenic pig has been performed tremendous development with introduction and knockout of many genes. However, efficiency of porcine somatic cell nuclear transfer is still low and embryo transfer (ET) is one of important step for production efficiency. In porcine ET for production of transgenic cloned pig, we can consider many of points to increase production rates. In respect of seasonality and weather, porcine ET usually is not performed in summer and winter. Cloned transgenic embryos must be transferred into reproductive tracts of recipients where embryos are located after natural fertilization with similar estrous cycle. If cloned embryos with 2~4 cell stage are transferred, they must be transferred into oviducts in periovulatory stage. Number and deposition sites of transferred cloned embryos are important. And we must compare the methods of ET between surgical and non-surgical ones in respect of production efficiency. Sow recipients after natural estrus is most preferred recipients however its cost is must be considered. Here we will review many of current studies about porcine embryo transfer to increase production efficiency of transgenic pigs and strategies for further studies.

• Journal of Embryo Transfer
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• v.5 no.2
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• pp.1-10
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• 1990

The individual difference of superovulatory responses and inferior embryo quality in superovulated cattle may cause disturbances in the endocrine profile, follicular steroidogenesis, nuclear maturation of nocyte, fertilization and cleavage of embryos. However, the reasons why those disturbances are occurred were not understood. The methods of the improvement of superovulatory response and embryo production were the use of anti-PMSG if PMSG used, pure FSH or controlled FSH-LH inducer, priming dose of gonadotropin in the first few day of the estrous cycle and GnRH or analogue. However, all of the above methods were not reduced the individual differences but improved embryo production We must continue the fundamental studies to understand the mechanism.

• Journal of Embryo Transfer
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• v.11 no.3
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• pp.301-307
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• 1996

This study was carried out to produce twin calves by embryo transfer in Hanwoo and investigate the pregnancy and twin rate by recipient's conditions. All recipients were bred at estrus by artificial insemination with Hanwoo semen and then transfered an additional embryo produced in vivo or in vitro to tbe uterine horn contralateral to the corpus luteum on Day 7. The results obtained were as follows ; 1. The pregnancy rate was higher in young recipients of 3 years (68.8%) than in old ones of 10 years and greater(36.4%). And for CL size pregnancy rate was 57.9, 45.4 and 60.1% in large, medium and small size of CL of recipients, respectively. 2. 447recipients were transferred an additional embryos at 7th day after Al and average pregnancy rate was 57.5% and twin production rate was 22.2%. 3. Average pregnancy and twin production rate by direct transfer methods of frozenthawed IVF embryos was 56.0 and 16.7%. 4. The ratio of male to female twin in a total of 55 twin pairs was 54.6%, and average gestation lengths of male to female and female to female twin were 280.6$\pm$5.4 and 279.715.4 days, respectively. Average birth weight of twins was beavior in male and male twin(23.2i5.8kg) than in male and female twin(20.5$\pm$2.6kg).

• Korean Journal of Plant Tissue Culture
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• v.26 no.1
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• pp.49-52
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• 1999

The influence of genotype and ecotype on the anther culture efficiency using hybrid of hot pepper (Capsicum annuum L.) was investigated. Anther culture efficiency was differently dependent on the genotype of parents. In the efficiency of embryo production, the cross combination using female parents with high embryo inducing ability was higher than those with low embryo inducing ability. It was shown that genotype and cytoplasm has effect on embryo production. Also the embryogenic ability was different according to ecotype of cross lines. The frequency of embryo production were the highest in Local variety $\times$ pimento cross combinations with 17.8~46.1 and the lowest in Pimento $\times$ Local variety cross combinations with 5.4~8.5%. Embryo inducing frequency was the middle value with 10.25~23.1% in Local variety $\times$ Tropical variety, Tropical variety $\times$ Local variety, Tropical variety $\times$ Pimento, and Pimento $\times$ Tropical variety cross combinations.

• Proceedings of the Korean Society of Embryo Transfer Conference
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• 1997.10a
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• pp.49-49
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• 1997

• Asian-Australasian Journal of Animal Sciences
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• v.15 no.3
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• pp.445-452
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• 2002

The main objective of modern reproductive technologies in pig reproduction is to increase reproductive efficiency and rates of genetic improvement. They also offer potential for greatly extending the multiplication and transport of genetic materials and the conservation of unique genetic resources in reasonably available forms for possible future use. The development and refinement of these technologies is concentrating on gamete and embryo collection, sorting and preservation, in vitro production of embryos, culturing, manipulation of embryos (splitting, nuclear transfer, production of chimeras, establishment embryo stem cells, and gene transfer) and embryo transfer. Also, the development of these novel technologies is facilitated by modern equipment for ultrasonography, microscopy, cryopreservation, endoscopy, and flow cytometry, microinjectiors, micromanipulators and centrifugation. The real impact on herd productivity will come from combining new reproductive techniques with powerful DNA technologies. The new reproductive techniques will allow a rapid turnover of generations, whereas the DNA technology can provide selection, which does not need phenotypic information when the selection decisions are made.

• Journal of Embryo Transfer
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• v.6 no.2
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• pp.18-29
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• 1991

Nuclear transplantation technique is known as the most potential and efficient method for producing a large number of genetically identical animals from a single embryo. The technical development of nuclear transplantation in mammals and its application to the production of cloned animals are described. For the efficient and successful production of cloned embryos by nuclear transplantation, the right selection and micromanipulation of recipient eggs or embryos as capacious recipient cytoplasm, the adequate and benefitlal preparation of multiple totipotent embryonic cells as donor nuclei, and also the fusion technique are very critical. Recent studies approaching to these critical points are introduced and discussed. Up to date, the overall efficiency of production of cloned embryos and offspring in livestock is estimated to be low. Further technical development of nuclear transplantation will enable large-scale production of cloned livestock and in near future the commercial cloning of animals will become a reality.

• Journal of Embryo Transfer
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• v.5 no.1
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• pp.21-27
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• 1990

The technique for maturation of follicular oocyte has been devised to provide such a low cost and in ptentifut number supply of bovine embryo. Some of problems concerning production of bovine embtyo in vitro were discussed in this paper. Bovine follicular oocytes cultured in vitro achieved normal fertilization but cleavage rates to blastocyst were low compared to the oocyte matured in vivo. It has been concluded that a deficient cytoplasmic maturation occurs in the oocytes matured in vitro. These results indicate that the studies for maturation of bovine follicular oocytes in vitro need improvement of culture conditions and to define the characteristics that might be indicative of healthy oocyte.

• Journal of Embryo Transfer
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• v.9 no.3
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• pp.229-234
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• 1994

This experiment was carried out to develop the model system for mass production of biomedical and nutritional proteins (human proteins) through mamraary gland of the transgenic cattle produced by gene manipulation and embryological technologies. Human growth hormone gene fused with rat $\beta$-casein gene promoter was microinjected into pronuclei of one cell bovine embryos produced by in vitro fertilization. After microinjection, embryos were cultured in vitro for 6 or 7 days. Twenty embryos reaching to blastocysts were transferred to 10 beef recipients, each receiving two embryos. Recipients were diagnosed for pregnancy by rectal palpation at 76 days after embryo transfer. One of them was pregnant to term and produced a female calf weighing 21 kg at 280 days following embryo transfer. DNA was extracted from umbilical cord tissue and blood of calf born for confirming gene insertion. As determined by Southern hybridization, the transgene was not found.