• Journal of Embryo Transfer
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• v.25 no.4
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• pp.247-250
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• 2010

• Journal of Animal Science and Technology
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• v.66 no.5
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• pp.920-935
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• 2024

Embryo transfer plays a crucial role in enhancing the breeding value of livestock; it has been applied in Hanwoo cattle, which is a popular breed for beef production in Korea. Both in vivo-derived (IVD) and in vitro-produced (IVP) embryos are used for this purpose; however, IVP embryos have been preferred recently owing to advancements in ovum pick-up (OPU) technology and genomic selection. Despite technological advancements, comprehensive data on large-scale OPU/IVEP/embryo transfer in Hanwoo cows are lacking. In this study, 16 elite Hanwoo donor cows were selected on the basis of specific criteria. Oocytes were retrieved from 241 cows using OPU. The collected cumulus-oocyte complexes (COCs) were matured, fertilized, and cultured in vitro to produce transferable embryos. Embryos were classified according to their developmental stage and then transferred to 675 recipient cows. A total of 3,317 COCs were collected, with an average of 13.76 COCs per cow. The number of transferable embryos produced per cow was 3.7. Hanwoo OPU-derived IVP embryos exhibited a higher production yield than the global average, indicating a stable IVEP environment. Both fresh and frozen IVP embryos yielded similar conception rates; hence, the use of vitrified-thawed embryos in transfer plans feasible. However, frozen-thawed embryos at Stage 7 had a lower conception rate than those at earlier stages. There was no significant difference between the conception rates of sexually mature heifers and postpartum cows used as recipients. The male-to-female offspring ratio increased as the developmental stage progressed. Seasonal effects on conception rates were not observed; however, higher abortion rates and a higher proportion of male offspring were observed during winter. This study provides valuable data for the Korean embryo transfer industry, enabling more strategic growth of the domestic Hanwoo embryo industry.

• Journal of Embryo Transfer
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• v.26 no.3
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• pp.153-158
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• 2011

This study was performed in order to simplify the operation and minimize stress of donor and be readily available in the field with low cost and high quality embryos using the Direct Embryo Collection (DEC). Donors, at random stages of the estrous cycle, received a CIDR. 7 days later, 200 mg FSH was treated with 40, 30, 20, 10 mg FSH levels in declining doses twice daily by intramuscular injection for 4 days. On the 3rd day administration of FSH, 25 mg $PGF_2{\alpha}$ was administered and CIDR was withdrawn. After FSH injections were complete, donors were artificially inseminated twice at 12 hr intervals. The donor cattle received 250 ${\mu}g$ GnRH at time of 1 st insemination and embryos were recovered 8 days after the 1st insemination. Embryo collection from superovulated donors was performed to flushing by non-surgical methods of 3-way, 2-way and DEC (l-way). The average number of recovered embryos were 11.25${\pm}$0.63, 12.5${\pm}$0.65 and 11.75${\pm}$0.48 from operations of 3-way, 2-way and DEC methods, respectively. There were no significant differences among the embryo collection methods. Also, The average number of transferable embryos were 6.25${\pm}$0.48, 7.25${\pm}$0.48 and 7.25${\pm}$0.63 from each embryo collection procedures. The number of transferable embryos was no differences among the 3-way, 2-way and DEC methods, respectively. Meanwhile, the ratio of transferable embryos for all recovered embryos from DEC methods was higher as 61.7 % than 55.6 %, 58 % from methods of 3-way, 2-way. And the flushing solution required for recovering embryos by DEC method was significantly lower as 0.28${\pm}$0.32 1 than 1.8${\pm}$0.12 1, 1.75${\pm}$0.10 1 from 3-way, 2-way methods (p<0.05). Also, the time required for recovering embryos by DEC methods was significantly lower as 27${\pm}$2 min than 51${\pm}$3, 45${\pm}$2 min, respectively (p<0.05). In conclusion, these results suggest that DEC method for embryo collection may be effectively used for production of in vivo embryos using less flushing solution and, it might be effectively available in the field compared to conventional embryo recovery methods using 3-way or 2-way balloon catheter.

• Journal of Embryo Transfer
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• v.29 no.3
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• pp.257-264
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• 2014

Recently, several approaches have been used to measure the oxygen consumption rates of individual embryos, but relationship between oxygen consumption and pregnancy rates of Hanwoo following embryo transfer has not yet been reported. In this study, we investigated the correlation between oxygen consumption rate and pregnancy rates of Hanwoo embryo using a SECM. In addition to, the expression of apoptosis-related genes was determined using real-time PCR by extracting RNA according to the oxygen consumption of in vivo embryo. First, we found that the oxygen consumption significantly increased in blastocyst-stage embryos (blastocyst) compared to early blastocyst stage embryos, indicating that oxygen consumption reflects the embryo quality (Grade I). The oxygen consumption or GI blastocysts were significantly higher than those of GII blastocysts ($10.2{\times}10^{14}/mol\;s^{-1}$ versus $6.4{\times}10^{14}/mol\;s^{-1}$, p<0.05). Pregnant rate in recipient cow was 0, 60 and 80% in the transplantation of embryo with the oxygen consumption of below 10.0, 10.0~12.0 and over $12.0{\times}10^{14}/mol\;s^{-1}$, respectively. Apoptosis regulatory genes, Hsp-70.1 were significantly increased in over-10.0 group than below 10.0 group but in Caspase-3, Bax and P53 gene, there was no significant difference. In conclusion, These results suggest that measurement of oxygen consumption maybe help increase the pregnant rate of Hanwoo embryos.

• Journal of Animal Science and Technology
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• v.62 no.6
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• pp.959-959
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• 2020

• Journal of Embryo Transfer
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• v.21 no.2
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• pp.147-156
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• 2006

The objective of this study was to supply excellent genetic resources to livestock farms by transferring embryos produced by genetically superior Korean cows (Hanwoo). Eighty Hanwoo donors were superovulated with gonadotropin ($Folltrpin^(R)\;or\;Antorin^(R)$) for 4 days combined with or without progesterone releasing intravaginal device (CIDR) insertion. The collected fresh or frozen-thawed embryos were transferred to 226 farm recipients. In this study, the effect of CIDR insertion in combination with gonadotropin ($Folltrpin^(R)$) treatments initiated at the random stage of estrous cycle on embryo production was evaluated and compared to conventional superovulation protocol. Moreover, the effect of gonadotropin ($Antorin^(R)$) dose in CIDR-treated Hanwoo donors on the embryo yield was determined. In addition, the effects of embryos (fresh vs. frozen-thawed), embryo transfer person, seasons and farms on the pregnancy rate were evaluated. In Hanwoo donors, CIDR insertion in combination with $Folltrpin^(R)$ treatments regardless of estrous detection resulted in increased numbers of total ova (6.5 vs. 5.8) and transferable embryos (3.9 vs. 3.2) compared to the conventional superovulation protocol (p<0.01). In CIDR-treated Hanwoo donors, the higher dose of $Antorin^(R)$ (36 vs. 28 mg) resulted in the increased number of transferable embryos (8.3 vs. 5.4, p<0.05). The embryos (fresh 43.9% vs. frozen-thawed 23.1%) and embryo transfer person (53.9 vs. $0{\sim}16.7%$) significantly affected the pregnancy rate after embryo transfer (p<0.01). These results suggest that CIDR-based superovulation protocol may be effectively used for production of superior Hanwoo embryos and, multiple ovulation and embryo transfer in Hanwoo might be effectively applied for livestock improvement if pregmancy rate with frozen-thawed embryos and embryo transfer skill would be improved.

• 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).

• Journal of Animal Reproduction and Biotechnology
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• v.34 no.1
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• pp.50-56
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• 2019

These studies were conducted to evaluate developmental competence of follicular oocyte collected from the ovaries of Hanwoo cows with the high offspring meat quality (1++ and 1+ grade). Cumulus oocyte complexes from individual cows were matured, fertilized and cultured using protocols of in-vitro maturation (IVM), invitro fertilization (IVF) and in-vitro culture (IVC). The rates of blastocyst development from Hanwoo cows with the offspring meat quality grades of 1++ and 1+ were 18.6 and 21.2%, respectively. The rates of blastocyst development were 26.3, 20.7, 20.7, 17.2 and 31.2% from Hanwoo cows with the meat quality grades of 1++, 1+, 1, 2 and 3, respectively. Fiftyseven transferable embryos were recovered from 11 Hanwoo donor cows (5.2/head) with the high offspring meat quality grades of 1++ and 1+ in vivo, and the pregnancy rate after embryo transfer was 61.1%. In conclusion, these results suggest that in vitro embryo production from the ovaries of cows with the high meat quality grades using individual culture system can be used an efficient method for livestock improvement. In addition, for the successful industrialization of embryo transfer, conception rate should be improved.

• 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.25 no.1
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• pp.57-66
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• 2010

The conception rate of cow is a major factor in farm management. The environment of farm and management of cow are the best influencing factors on conception rate, and the fertility of bull is the second influencing factor. In Hanwoo bull, however, the informations limited to performance and carcass traits have been offered to Hanwoo farmer. Therefore, this study analysed the estimated relative conception rates (ERCR) for estimation of fertility of bulls, using the 8,892 mating data with 116 heads of prove bull to produce progeny. Mean of least square means of conception rate after first insemination was 50.95% in bull herds. On the standard of this mean, ERCRs after first insemination of each bull were analysed. Values ranged from -26.1% to +21.0%, the difference was 47.1%. Among 116 heads of bull analysed, KPN582 showed the highest ERCR as 21.0%, KPN550 (18.3%), KPN656 (16.7%), KPN632 (15.8%), KPN690 (14.9%) were gone behind, but KPN621 was the lowest as -26.1%, KPN680 (-21.3%), KPN674 (-16.2%), KPN569 (-15.9%), KPN699 (-14.9%) were succeeded. If ERCRs of Hanwoo bull will be offered to Hanwoo farmer, it will be worthwhile.