This study was undertaken to determine whether the presence of fertility-associated antigen (FAA) in semen would influence semen characteristics and conception rate of artificial insemination in Hanwoo. The response to FAA of 36 heads of proven bull, 7 heads of young bull, and 27 heads of performance-tested bull was that one proven bull was FAA-negative and the others were FAA-positive, therefore FAA-negative bull was 1.4%. FAA-negative bull was lower in first and second semen concentrations than those of FAA-positive bull in 5,301 semen of 21 heads of proven bull, then FAA-negative bull was fewer as 11.5% in total sperm counts. The estrus of 22 heads was 70d-nonreturned in 36 cows first inseminated with frozen semen of FAA-negative bull, but that of 249 heads in 378 cows first inseminated with frozen semen of FAA-positive bull. Each conception rate was 61.1% and 65.9%, respectively. The difference of conception rates was 4.8%. These results indicate that the response of FAA to semen were influenced semen characteristics and conception rate of artificial insemination, but further investigations are needed to confirm the results.

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.

The relationships of scrotal circumference (SC) to semen characteristics and the conception rate (70 days-nonreturn rate) of artificial insemination in farm were studied with 137 heads of bull in Hanwoo. The average and range of SC were cm and 26.0~52.5 cm, respectively. Hanwoo bulls were classified with SC, divided into 34 cm below group, 34~39 cm group, and 39 cm over group. The 5,487 semen records of 43 heads of bull from July. 1. 2007 to June. 30. 2008. were used to determine the relationships between SC and semen characteristics. The semen concentration and total sperm number of each group were 11.18, 16.68, and , and 69.83, 101.64 and /ejaculate. The bulls with 34 cm or more SC were higher than the bulls with 34 cm below in semen concentration and total sperm number (p<0.01). But between SC and semen volume have no significant relationship (p>0.05). The 9,862 mating records of 44 farm with 137 heads of bull were used to determine the relationships between SC and conception rate. The conception rate of 1st artificial insemination were 73.31, 74.16, and 77.33 % in each group. Also SC was positively correlated with pregnancy rate (r=0.12, p=0.17). These results indicate that SC correlates positively with semen characteristics, and maybe with pregnancy rate in Hanwoo.

한우 종모우에 있어 정액 채취시 승가 조건(의빈우 혹은 의빈대)이 정액성상에 미치는 영향을 구명하기 위하여 의빈우 승가 종모우 21두, 의빈대승가 종모우 9두 등 보증 종모우 30두를 공시하여 연구하였다. 정액은 일 간격으로 채취하였으며 채취 당일 1시간 간격으로 총 2회 정액 채취하여 6개월간 정액성상을 조사하였다. 의빈대 승가 종모우가 의빈우 승가 종모우보다 1차 및 2차 정자농도에 있어 유의적으로 높아(p<0.05) 1차 및 2차 총 정자수에서도

한우 종모우의 고환둘레와 정액성상 그리고 후대희 성장 및 도체성적과의 관계를 구명하기 위하여 4~8세 한우 종무우 92두를 공시하였으며 8,628개의 종모우 정액성상 그리고 종모우 후대 814e의 성장 및 도체성적을 이용하였다. 종모우의 고환둘레는 38.73.73 cm, 1차 정액량, 정자농도 및 총정자수는 각각 5.63mL, 17.9/mL 및 100.34/ejaculation 이었고 2차 정액량, 정자농도, 및 총정자수는 각각 5.32mL, 15.0/

To identify an antioxidant system, Se and Vit. E were administered into Hanwoo young sire and the effects of administration on blood components(Se, Vit. E, chemical values, estradiol-17 , testosterone) were examined. The 16 heads ranging from twenty to thirty two months of age were randomly assigned to control group, Se-administered group(Se-group), Vit. E-administered group(Vit. E-group) and Se and Vit. E administered group(Se and Vit. E-group). Each reagent (Se : 0.1 mg, Vit. E . 1,500IU, Se+vit. E : 0.1 mg+1,500IU per kg of body weight, respectively) administered 3 times every 30days by intramuscular injection. Se concentration in serum was higher in Se-group and Se and Vit. E-group than in control group and Se and Vit. E-group also was higher than Vit. E-group(p<0.05). Although all Se-, Vit. E-administered groups were a little higher than control group, the injection of Se and Vit. E were not significant effect on Vit. E concentration in serum(p>0.05). All groups showed significant variance by periods, but there were not significantly different among groups in blood chemical values. The estradiol-17 concentrations of all Se-, Vit. E-administered groups were a little higher than those of control group, but there were not significant(p>0.05). There have no significant difference among groups in testosterone concentration. These results indicate that the administration of Se, Se + Vit. E increase Se concentration in Hanwoo young bull.

This study was carried out to establish an effective system for embryo transfer techniques by analyzing several factors affecting in-vivo embryo transfer in Korean cattle. Embryos produced in-vivo were transferred into a total of 301 recipients The results obtained in studies on the factors affacting pregnancy rate after embryo transfer by condition of recipients were as follows ; 1. The pregnancy rate by age and parity of recipients showed high in 5~8 and over 12 years old(72.7~73.9%), and 3rd~4th parity(82.1%) for fresh embryos(P<0.05). The pregnancy rate did not differ by age and parity of recipients in frozen embryos. The pregnancy rate of frozen embryos tended to be similar to that of fresh embryos(38.5% and 25.0~36.7%). 2. The number of observation for normal estrus cycles of recipients did not differ In pregnancy rate between one and 2 times in fresh embryos(64.9%, 69.8%). The pregnancy rate by transferred frozen embryos showed significantly higher after 2 times of observation(P<0.05, 16.3%, 37.5%). The pregnancy rate by days open did not differ between fresh and frozen embryos. But the pregnancy rate was slightly higher in 12 months and 6 months of days open for fresh and frozen embryos, respectively(70.1~71.1% and 24.5%, respectively). 3. The pregnancy rate of transferred fresh and frozen embryos into right and left side of uterine horn did not differ(62.1% : 65.9% 25.0% : 24.3%, respectively). The pregnancy rate by the grade of CL was not different in fresh embryos, but the pregnancy rate was significantly higher in the grade A than B for frozen embryos(P<0.01, 43.2%, 16.2%).

This study was carried out to establish an effective and practical system for commercialization of embryo production techniques by analyzing several factors influencing in vivo embryo production on condition of donors treated FSH-P and SUPER-OV in Korean native cattle. In vivo embryos were flushed 226 times from 128 donors. The results obtained for the factors influencing in vivo embryo production by conditionof donors treated FSH-P and SUPER-OV were as follows :1. Age and parity of donors did not affect the transferable and freezable embryos among the treatments in FSH-P but the transferable and freezable embryos were decreased after 6 years old and 4th parity in SUPER-OV(P<0.01). 2. The production of embryos on the weight of donors was higher in over 400kg of body weight in FSH-P(P<0.01) and was higher in over 450kg than 400~450kg of body weight in SUPER-OV(P<0.05). For FSH-P embryo production was better responded in 350~450kg of body weight with 30~32mg doses, and showed a better result in over 450kg body weight with 32~34mg doses.(Key Words : in vivo embryo, donors, FSH-P SUPER-OV)

핵 이식 기술을 이용한 cloning 송아지 생산이 처음 보고(Prather et al., 1987) 된 후, 소 수정란 Cloning에 대한 많은 연구가 분자 생물학 등 여러 분야에서 꾸준히 계속되고 있다. 이 기술은 빈우의 번식 능력을 향상시켜 유전적 개량량을 증대할 수 있는 번식과 육종을 위한 도구로써 많은 잠재력을 지니고 있다. 최근 핵 이식 기술을 이용하여 유전적으로 우수한 빈우로부터 수천개의 수정란을 생산하여, 이들 수정란에게 생산된 송아지가