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 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 of techniques by analyzing several factors affecting the gestation length and the weight changes of calves produced from embryo transfer in Korean cattle. The results obtained in study on factors affecting the gestation length and the weight changes of calves produced from embryo transfer were as fallow; 1) The gestation length and the birth weight did not differ between male and female, but the weight changes after birth were remarkablely different between sex(P<0.05). 2) The gestation length between heifers and cows was not different, and body weights at birth and 6 months were remarkabley heavy in cows(P<0.05). Weight changes after 6 months were not different. 3) The gestation length and the birth weight were significantly different between the single and twin calving (P<0.05). Weight of twin at 6 and 12 months were remarkabely light. 4) Calving seasons did not affect the gestation length the and the birth weight. Weaning weight was significantly heavy(P<0.05), but weight changes after weaning were no different among the calving seasons. Conclusivley, this results suggest that cows will be better when considering growth of calves and twin produced from embryo trnsfer in Korean cattle.

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 affecting pregnancy rate after embryo transfer by condition of embryos were as follow ; 1. The pregnancy rate of 301 recipients was 45.2% and higher with fresh embryos than with frozen embryos(63.5% : 21.4%, P<0.01). Embryos superovurated by FSH-P had slightly greater than by SUPER-OV in pragnancy rate, athough these were no difference between two treatments. 2. The pregnancy rates of transferred morulae and blastocysts showed no difference between fresh and frozen embryos(63.5% : 63~6% ; 20.0% : 25.8%). However, the pregnancy rates by quality of flesh and frozen embryos were significantly different(P<0~05). The pregnancy rates were outstandingly high in the grade A, B of fresh embryos(59.0~66.4%), and in the grade A of frozen embryos(43.6%). 3. The number of transferred embryos showed no difference in pregnancy rate, but when frozen embryos transferred, the pregnancy rate was slightly higher with two embryos than that with one embryo.

I. The Factors Influencing In Vivo Embryo Production by Condition of Superovulation Treatment These studies were carried out to establish an effective and practical system for comrnercialization of embryo production techniques by analyzing several factors influencing in vivo embryo production on superovulation treatment in Korean native cattle. In vivo embryos were flushed 226 times from 128 donors.The results obtained from the studies on the factors influencing in vivo embryo production by superovulation treatment were as follows : FSH-P had a significiant advantage(83.0%) over SUPER-OV in the percentage of fertilized embryos(P<0.01). No difference was found loetween FSH-P and SUPER-OV in the percentage of transferable and freezable embryos.2. The response of superovulation by SUPER-OV was greater than that of FSH-P The donors having 8~9 and more than 10 of corpora lutea(CL) derived by FSH-P were 40.0%(most frequent) and 33%, respectively. The donors having more than 12 and 10 CL derived by SUPER -OV were 33.3% (most frequent) and 56.6%, respectively.3. Embryo production after treatment of repeated superovulation was remarkablely decreased at 3rd time by FSH-P but did not differ among 1, 2 and 3rd times by SUPER-OV. Embryo production on intervals of repeated superovulation was significantly different for the number and percentage of fertilized, transferable and free-zable' embryos in FSH-P (P<0.01) and rernarkablely decreased in repeated superovulation of 81~120 interval days. The SUPER-OV showed no differences in interval days of repeated superovulation and was found better than FSH-P in the response of repeated superovulation. (Key words : in Vivo embryo, superovulation, FSH -P, SUPER-OV)