Embryos produced with serum show the alterations in their ultrastructure, impaired compaction, abnormal blastulation, aberrant mRNA expression profiles and large calf syndrome with greater incidences of stillbirths and deaths after birth. The aim of the present study was to describe in vitro embryo production by analyzing embryo production, fetal production and pregnancy rate in free-serum medium. The OPU-IVP data used in this study from 2016. Approximately, sixteen cows (Hanwoo), which belonged to the Institute of Gyeongsang National University, were used. Two experimental group is used in this study. Serum groups were conducted in March to July and free-serum group was conducted in September to December. The recovered cumulus-oocyte complexes were morphologically classified to four grades based on the compaction of cumulus cells layers and homogeneity of the cytoplasm. The number of oocyte was significantly greater in serum groups than that in free-serum groups (29.61 ± 0.63 vs. 15.6 ± 0.62; p < 0.05). Between serum and free-serum groups indicate that average of 1st and 2nd grade oocytes were no difference (2.38 ± 1.67 vs. 2.38 ± 1.48; p > 0.05), but number of 3rd and 4th grade oocytes were greater in serum groups than that in free-serum groups (7.31 ± 7.64 vs. 5.60 ± 6.29; p < 0.05). Embryo cleaved competence was higher in rate in free-serum groups than that in serum groups (62.1% vs. 58.3; p < 0.05). However, blastocyst developmental rate was no difference between serum and free-serum groups (33.1% vs. 43.5%; p < 0.05). 986 recipients were used for embryo transfer. Pregnancy rate was indicated that between serum and free-serum group was no difference (54.6% vs. 56.3%; p < 0.05). In conclusion, we developed the free-serum system for production of in vitro bovine embryos in order to meet the developmental and qualitative requirements for large scale commercial use.

Up-to-date artificial insemination (AI) using frozen sperm consider as the most widely using technology for improvement of Korean Native Cow (Hanwoo) embryo production. However, it is time consuming, required at least 15~20 years to make more than 6 generations, and their offspring number is limited. To overcome such limitations, superovulation and in vitro fertilization have been developed. For superovulation, the number of produced embryos are not enough for commercialization and donor cows need rest period. This led to use of slaughterhouse ovary for in vitro fertilization, but it is impossible to repeat the collection from the same individual and it only can improve the genetic merits of offspring for one generation. Production of embryos using Ovum Pick-Up (OPU) technique, where oocytes can be repeatedly collected from living elite donor, might overcome these limitations. In this study, we investigated the possibility of using OPU technique from donors at different age and different session periods for mass-embryo-production. Oocytes were collected from 26 donor cows twice per week, 3 - 4 months per year, between 2013 and 2016. Results showed that, the average number of embryo produced in first year used donor was significantly higher than that in second year used donor (3.89 ± 2.85 vs 3.29 ± 2.70), however, there was no significant difference between third year used donor (3.51 ± 3.32) and other groups. Taken together, our data showed that repeated using of donor up to three years is possible for in vitro embryo mass-production. Moreover, OPU can be used as suitable embryo producing technique for livestock breed improvement.

본 연구는 한약재 부산물을 조사료 대체 사료원으로서 사용하였을 때 발효기간에 따른 in vitro 발효 특 성을 조사하고자 수행되었다. 처리구는 대조구 (control), 한약재 부산물 20%와 볏짚 80% (T1), 한약재 부산물 40%와 볏짚 60% (T2), 한약재 부산물 50%와 볏짚 50% (T3), 그리고 한약재 부산물 100%와 볏짚 0% (T4)이었으며 3, 6, 9, 12, 24, 36, 48, 및 72h 동안 처리당 3반복으로 in vitro 발효실험을 실 시하였다. 가스 발생량과 건물소화율은 시간이 지남에 따라, 그리고 한약재 부산물의 양이 많아짐에 따라 서 증가하는 경향이었으며, 특히 72시간에 T4가 가장 높았다 (P<0.05). 메탄 발생량 또한 비슷한 결과 로서 시간이 경과하고 한약재 부산물의 양이 많아짐에 따라 지속적으로 증가하였다 (P<0.05). pH는 5.39~6.80의 범위로 첨가량이 높아질 수록 유의적으로 낮아졌다 (P<0.05). 미생물 성장량은 발효 후 시 간이 경과함에 따라서 점차적으로 증가하였고, 첨가구가 control 보다 높았다 (P<0.05). CMCase, Xylanase 및 amylase 효소 활력은 처리구별 특정한 패턴이나 유의적인 차이가 없었다. 본 실험의 결과는 한약재 부산물이 가스발생량, 미생물성장량 및 건물소화율을 높이고 pH를 감소시키는 등의 효과를 주어 반추위 발효의 안정화 및 향상을 꾀할 수 있고, 효소 활력을 높임으로써 사료의 이용효율을 향상시킬 수 있다는 가능성을 보여 주었다