본 연구는 과배란처리에 의한 수정란이식 시 우수한 수정란을 다량 확보하고 이식 후 수태율 향상을 위하여 공란우 및 수란우에 bST처리가 수정란회수를 및 수태율에 어떠한 영향을 미치는가를 조사하고자 실시하였다. 공란우는 Folltropin-V와 PGF를 이용하여 과배란처리를 유도하여 12시간 간격으로 2 straw치 3회 인공수정을 실시하였다. 공란우와 수란우는 대조구와 bST처리구로 구분하였으며, bST(500 mg)처리는 발정발현 후 미근부에 근육주사

This study was carried out to establish the techniques for producing the calves of genetically superior Korean Native cattle by transfer of frozen-thawed embryos. The effects of some factors related to embryo recovery following superovulation and pregnancy rate following transfer of frozen-thawed embryos were evaluated. Also calving state was investigated. The results obtained were as follows ; The mean number of total and transferrable embryos recovered per superovulated cow was 8.72 and 4.90, respectively, from a total of 72 superovulations using 34 donor cows. There were no significant differences in the number of total or transferrable embryos recovered per superovulated cow between products of follicle stimulating hormone (FSH), years, seasons, and collection numbers. The pregnancy rate was found 44.44% following transfer of frozen-thawed embryos of Korean Native cattle to a total of 180 recipient cows including 82 Angus, 27 Charolais, 62 Hereford and 9 Korean Native cows. The pregnancy rate was significantly (P<0.05) higher in the transfer of excellent (42.99) and good embryos (40.17%), compared with fair (5.90%) grade embryos. And the pregnancy rate was significantly (P<0.05) higher in the transfer of embryos of morula stage (43.86%) than blastocyst stage (15.51%). But there were no significant differences in pregnancy rates between natural and induced estrus estrus asynchrony of 1 days, breeds, and parities of recipient cows. The normal calving rate of 80 pregnant cows following transfer of frozen4hawed em-bryos was 87.5% and the other 10 pregnant cows showed abortion during the period from pregnancy diagnosis at 50~60 days to calving. The average gestation length of normally delivered recipients was 288.50 days and the average birth weight of 70 calves born was 24.22 kg. The gestation length was significantly (P<0.05) shorter in the recipients delivering female calves (286.70 days) than males (289.39 days). But there were no significant differences in gestation tength and birth weight of calves born between the recipient breeds.

This study was carried out to propagate Korean native cattle using beef recipients by embryo transfer. Seven Korean native cattle donors were superovulated with FSH 32mg and Embryos collected from donors were frozen and preserved in National Animal Breeding Institute. Frozen-thawed embryos were transferred to synchronized 40 beef recipients nonsurgically in Daekwanryeong Branch of National Animal Breeding Institute. The results obtained were as follows : 1. Total ova and transferable embryos per donor were 11.4 and 11.1 from 7 donors, respectively. 2. Among 40 recipients transferred with frozen-thawed embryos, 20 were pregnant(50.0%). 3. The pregnancy rate according to time from embryo thawing to transfer was higher when transferred within 3 hours than after 3 hours(57.6% vs. 14.3%). 4. The cow recipients showed slightly higher pregnancy rate than the heifer(53.3% vs. 48.0%). 5. Two grade embryos showed higher pregnancy rate than 1 grade(66.7% vs. 45.2%).

본 시험은 고랭지(해발 800m)에서 매초용 옥수수의 추비시기가 생육 및 건물생산에 미치는 영향을 구명코자 수원19호와 강원재래백을 공시하여 198년年 5월 16일에 국럽종축원 대관령지원 시험포장에서 시험을 실시힌바 그 결과를 요약하면 다음과 같다 추비시용 시기의 조만에 따라 작물생육특성인 초장, 웅수의 출현기, 경의 직경, 착수고등의 변화는 거의 없였으며 lOa당 건물수량 및 식물체부 위별 건물수량비솔에 있어서도 처리간에 큰 차이가 인정되지 않았다.