• Journal of Embryo Transfer
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• v.26 no.1
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• pp.27-32
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• 2011

This study evaluated the effect of recipient's breed on the gestation length and birth weight of Hanwoo calves produced by Hanwoo ovum pick up (OPU) derived embryos. Embryos of OPU derived Hanwoo cows were transferred into the Hanwoo and Holstein recipients at 6~7 days of estrus cycle. Gestation length was expressed in days from the day of embryo transfer to the birth day of offspring, and birth weight of offspring was recorded within 24 h of birth. Breed of recipient cows (Hanwoo and Holstein) has no effect on overall gestation length ($280.9{\pm}6.2$ vs. $284.4{\pm}9.8$ days) and birth weight of calves ($23.56{\pm}3.75$ vs. $27.70{\pm}7.92\;kg$). The gestation length was higher (p<0.05) for male calves than female calves in both Hanwoo ($283.8{\pm}6.7$ vs. $277.3{\pm}3.3$ days) and Holstein ($287.3{\pm}8.9$ vs. $280.1{\pm}9.1$ days) recipient cows. Birth weight of Hanwoo calves did not differ when Hanwoo recipients ($26.5{\pm}1.3$ vs. $23.3{\pm}1.2\;kg$) were used for embryo transfer. However, male calves were heavier (p<0.05) at birth than that of female calves when embryos were transferred into the Holstein cow ($33.5{\pm}4.9$ vs. $27.8{\pm}4.9\;kg$). In conclusion, the present results demonstrated that breed of recipient cows have no effect on gestation length and birth weight of OPU derived Hanwoo calves. However, gestation length and birth weight of male calves were higher in both Hanwoo and Holstein recipient cows.

• Journal of Embryo Transfer
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• v.30 no.3
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• pp.189-193
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• 2015

Calculating break-even price of calf production is closely associated with reproductive efficiency. To determine the price, we need data from reproduction records including number of claves weaned, number of cows exposed for breeding, and annual cash coast per cow, and average weaning or market weight of claves sold and retained. Unfortunately, the data were not available in Korea native cow (Hanwoo). To evaluate the performance and the price, we collected calving interval from about 60,000 cows for last 10 years and estimated reproductive performance. Calving interval was increased 4.3% and pregnancy rate was decreased about 1.4~2.8% year-on-year. Increases in growth rates of number of cow and semen per calf supported the low reproductive performance. Finally, break-even price was calculated using estimated percent calf crop and demonstrated that growth rate of break-even price is larger than that of annual cash per cow, suggesting cow-calf profitability and financial efficiency in Korea native cow (Hanwoo) is getting worse.

• 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.31 no.2
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• pp.109-116
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• 2016

The recovery of epididymal sperm in animals is considered as one of the important tools to preserve high value or endangered species. However, there are no appropriate castrating indicators such as months of age in bull, sperm morphology, and motility, particularly in young Korean native bull (Hanwoo). Therefore, this study aimed to investigate sperm number, morphology, and motility of sperm in the epididymis tail of young Hanwoo bulls at 8 and 15 months of age. After castration, epididymal tails were collected and minced with blades to recover sperm. In experiments 1 and 2, sperm number, morphology, and motility were examined. Total number of sperm and percentage of normal sperm from bulls at 8 months of age was lower than that of bulls at 15 months of age after collection (P<0.05). Percentage of abnormal head, tail, proximal cytoplasmic droplet, dead and damaged acrosome of sperm from bulls at 8 months of age were higher than those of bulls at 15 months of age (P<0.05). In experiment 3, sperm motility from bulls at 8 and 15 months of age were examined before freezing and after thawing. Frozen-thawed sperm at 8 months of age showed low total motility and motile sperm with ${\geq}25{\mu}m/sec$ compared to those at 15 months of age and commercially-used sperm (P<0.05). In conclusion, sperm derived from the epididymal tail of bulls at 8 months of age showed high abnormal morphology and poor motility, which are not adequate for AI and IVF. On the other hand, sperm derived from the epididymal tail of bulls at 15 months of age showed high normal morphology and motility.

• Reproductive and Developmental Biology
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• v.32 no.3
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• pp.175-181
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• 2008

This study was conducted to investigate an effective recipient oocyte and culture system for producing of Hanwoo (Korean native cattle) somatic cell nuclear transfer (SCNT) embryos. Hanwoo ear skin fibroblasts were used as donor cells. In vitro matured Hanwoo or Holstein oocytes were enucleated, and single donor cells were transferred into the perivitelline space of the enucleated oocytes. The couplets were subsequently fused and activated. The reconstructed embryos were cultured in a conventional or sequential culture system. In the former, embryos were cultured in CR2aa medium for eight days; in the latter, embryos were cultured in modified CR2aa-A (mCR2-A) for three days and then further cultured in modified CR2aa-B (mCR2-B) for five days. In the experiment with the recipient oocyte, the rate of embryo development to the blastocyst stage was significantly (p<0.05) higher in Hanwoo recipient oocytes than in Holstein ones (48.8% vs 38.9%). BIastocysts derived from Hanwoo recipient oocytes contained significantly (p<0.05) higher numbers of total cells than those derived from Holstein recipient oocytes ($156.0{\pm}68.2$ vs $134.7{\pm}54.8$). There was no difference in the mean proportion of apoptotic cells in blastocysts between the sources of recipient oocytes. In the experiment with the embryo culture system, the blastocyst rate was somewhat higher in sequential system than in conventional system (50.0% vs 43.5%), though there was no significant difference. The numbers of total ($160.0{\pm}69.0$ vs $156.7{\pm}68.4$) and apoptotic cells ($14.0{\pm}10.4$ vs $11.8{\pm}6.4$) were not different between the culture systems. In conclusion, the present study demonstrated that Hanwoo recipient oocytes and the sequential culture system were more effective in supporting the production of Hanwoo SCNT embryos.

• Journal of Embryo Transfer
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• v.23 no.4
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• pp.251-255
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• 2008

The aim of the present recent study was to compare the protein patterns in the vaginal mucus of Hanwoo cattles during spontaneous and CIDR induced-estrus. Ten cattles, who had been observed in estrus, received no treatment and served as the group of cattles with normal spontaneous estrus. Thirteen cattles in the CIDR received an CIDR insert on day 14 were removed and cattles were injected GnRH on day 15. Vaginal mucus samples were collected from all cattles at the same time the single AI in cattles with spontaneous estrus and the AI in cattles with induced estrus. Spontaneous and CIDR-induced estrus vaginal mucus samples were analyzed on two different array surfaces: cation-exchange (CM10), anion-exchange (Q10). In addition, using the NaCl solution by which the proteins combined after washing are 0.5, 1 and 2 M, it was fractionated and a protein was collected successively. The results are summarized as follows: 1) Ionic surfaces chemistries (Q10 and CM10) gave the best results in terms of detectable protein peaks, with more than 100 protein peaks in the two fractions and under each condition. 2) Protein mass spectrometer using 11 different proteins in protein identification of 7 were able to determine the protein. List of identified proteins as follows; Ribosome-binding protein 1, GRIP 1-associated protein 1, Katanin p60 ATPase-containing subunit A-like 1, Protein FAM44A, DUF729 domain-containing protein 1, Prolactin precursor, Dihydrofolate erductase. Conclusively, on the basis of this study, protein expression in the vaginal mucus could be used as an indicator for time of estrus manifestation in order to increase conception rates by applying AI at an optional time.

• Journal of Embryo Transfer
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• v.20 no.3
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• pp.311-315
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• 2005

This study was conducted to investigate the effects of disregarding of heat detection on embryo production in superovulation of Hanwoo cows. Donors which showed 1 or 2 times of normal heat and had no abnormality of reproductive tract were selected The superovulation was performed injection of 2.5 mL FSH (Antorin R-10, Japan) 2 times on 5 days before next heat and continuously with the reduction of dose to 0.5 mL of first injection 2 times in a day for next 3 days. Otherwise, the donors of CIDR group were inserted CIDR plus (with the capsule of estradiol benzoate 10 mg) on Day 10 from standing heat for 9 days. On 6 days from insertion of CIDR, FSH was injected above same manners. The response according to the natural heat and CIDR were $82.2\%,\;89.7\%$, respectively. There were no difference between both treatments. The recovery rates of embryos were 7.7, 10.5, respectively and transferable embryos were 3.4, 3.8. There showed significant difference between both treatments (p<0.05). These results suggested that disregarding of heat detection in superovulation could be produced transferable embryos for embryo transfer and preserve the donors from the excess hormonal administration and maintain the economical lift span of genetically available Hanwoo donors.

• Journal of Embryo Transfer
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• v.15 no.2
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• pp.115-120
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• 2000

This study was undertaken to test the hypothesis the hypothesis that treatment with hCG (5,000 IU) at the time of embryo transfer would enhance pregnancy rates in recipients, and the concentration of plasma urea nitrogen(PUN) in recipients was related to the effect of hCG on the reproductive performance. Blood samples were taken according to experimental condition for the assessment of the endogenous plasma progesterone concentration and plasma urea nitrogen. Concentrations of progesterone in plasma were higher in cows treated with hCG on day 7(estrus=day 0) than in those untreated during 7∼43 days after insemination. The pregnancy rates were 65.5 and 54.6% for the hCG treated and untreated groups, respectively. In recipient group categorized with PUN concentration of <12 mg/이, the pregnancy rates were 68.8 and 46.7% for the hCG treated and untreated groups, respectively. The results suggest that hCG treatment at 7 days after insemination could be used to increase the pregnancy rate of embryo transfer, and transfer, and only the recipients with PUN concentration of <12 mg/dl were influenced by treatment with hCG.

• Journal of Embryo Transfer
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• v.18 no.1
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• pp.81-84
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• 2003

This study was performed to produce Hanwoo-fetal fibroblast cell clone transferred to Holstein recipient. It was coming on the parturition but didn't show parturition signs until 272 days from the embryo transfer. For the induction of normal parturition, dexamethasone (20 mg) were injected with IM on 272 day and PG $F_{2a}$ (25 mg) plus estradiol (20 mg) was injected with IM after 24hrs. Forty-eight hours after dexamethasone injection, we could find parturition signs and delivered healthy male of offspring (40 kg) about 50 hrs after it's injection. However the recipient was showed retention of afterbirth.h.

• Journal of Embryo Transfer
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• v.32 no.3
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• pp.171-176
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• 2017

This study was conducted to investigate the breeding status of farms to improve the production efficiency of Hanwoo calf. The study was conducted on 45 farms divided into two groups. This study was conducted to investigate the breeding size and breeding area of Hanwoo cows. The average age at first delivery of Hanwoo was 28.7 months. The number of artificial insemination per pregnancy was $1.45{\pm}0.32$, and the number of artificial insemination days after birth was 119.8 days. Conception rates were $75.2{\pm}16.93%$ for small farms and $70.6{\pm}17.46%$ for medium sized farms and $71.4{\pm}11.03%$ for large farms. When we looked at farming methods, 'the farmers using estrus observation aids' had 10.42% higher calf production rate than the 'unused farmers'. The farms vaccinated with IBR and BVDV for breeding cattle showed a 4.41% decrease in abortion, stillbirth and mortality. According to farming conditions, conception rate and delivery rate improved by 3.47% and 18.29%, respectively, when grazing and exercising were performed. Observation, immunization and grazing were found to be important indicators for improving calf production efficiency in Hanwoo farm. This study can be used as a research data to improve the reproductive rate of farmhouse sites through the survey on the breeding status of Hanwoo farmers.