Uterine sterilization is important for improving fertility in cattle. This study compared bacterial flora in the uterus between healthy and repeat breeder cows (RBCs). The uterine flushing of six heifers, 13 healthy HanWoo cows and eight RBCs (HanWoo) were sampled, and 15 frozen semen samples were selected. Overall, 35 bacteria were identified from in HanWoo uterine flushing and semen. The bacterial genera identified from HanWoo uterine flushing were Alloiococcus, Bacillus, Enterobacter, Enterococcus, Erysipelothrix, Gardnerella, Granulicatella, Kocuria, Pantoea, Pasteurella, Rothia, Serratia, Sphingomonas, Staphylococcus, Stenotrophomonas and Streptococcus. The bacterial genera identified from HanWoo semen were Bacillus, Escherichia, Kocuria, Oligella, Pseudomonas, Serratia, Sphingomonas, Staphylococcus, Stenotrophomonas and Streptococcus. The prevalence and presence of the identified bacteria between healthy cows and RBCs differed significantly. Further studies are needed to determine the role of these bacteria in the uterus of HanWoo cattle with reproductive disorder.

The development of uterus in fetuses on 60, 90 and 120 days of gastation and neonates of Korean native goats was investigated by scanning electron microscopy. The results were summarized as follows; 1. in the 60-day-old fetuses, the short microvilli were sporadically observed on the luminal surface of the endometrium. 2. In the 90-day-old fetuses, the mucosal folds, polygonal microridges, numerous microvilli, flower-like-buds, and domeshpaed or crateriform area were also observed on the luminal surface of endometrium. 3. In the 120-day-old fetuse, the primordial caruncles(nodules) of the endometrium were developed conspicuously and long microvilli were developed densely. 4. In the neonates, thecaruncles and microvilli of the endometrium were more developed than those of 120-day-old fetuses.

Bacterial infection of the uterus in Hanwoo can kill embryos. Therefore, many antibiotics have been used to treat this infection in the uterus of repeat breeders. Incorrect use of antibiotics has led to resistance in bacteria. Natural compounds have used as substitutes for antibiotics because they are safe and have very mild side effects. This study was conducted to examine the antimicrobial effects of five extracts from medicinal plants including Humulus japonicas (Hj), Phelledendron amurense (Pa), Viola mandshurica (Vm), Carthamus tinctorius (Ct), and Chelidoni herba (Ch) on bacteria isolated from the uterus of Hanwoo using the paper disc diffusion method. Hj and Pa extracts had potent antimicrobial effects against Staphylococcus lentus, Streptococcus infantarius subsp. coli, and Bacillus pumilus. Pa had the greatest antimicrobial effect among the five medicinal plants and was effective against 19 types of bacteria from bovine uterus. Compared to Pa, Hj showed weaker antimicrobial effects on all the bacteria tested except Pseudomonas aeruginosa. Vm, Ct, and Ch also showed weak antimicrobial effects on the tested bacteria. The results obtained suggest that Hj and Pa are natural compounds suitable for treating bacterial infection in repeat breeders and improving conception rates of Hanwoo.

This study was carried out to determine suitable selection factors for recipients and embryos which could improve pregnancy rates following bovine embryo transfer. The experiment included 52 surgical transfers from February, 1985 through June, 1986 performed on Kyongbuk Breeding Center in southern Korea. The pregnancy rate was highest when recipients were in estrus within 6 hours before the donor to 12 hours after the donor (78.3 % versus 50 % for recipients in estrus earlier or later). Pregnancy rates were acceptable following culture under field conditions for up to 17 hours. More recipients over 15 months of age (76.1 %) remained pregnant than those under 15 months (66.7 %). Embryos transferred during the months from February to July resulted in higher pregnancy rates than those transferred during the remaining 6 months (77.3 % versus 57.1 %). Transferrable embryos were classified A (best) to C (worst); those graded A or B resulted in significantly higher pregnancy rates than those graded C (81.8 % and 73.3 % versus 25.0 %, p0.05). Pregnancy rates among recipients of the Korean native breed tended to be higher than among Holstein recipients (100 % versus 71.1 %). Similarly, when the embryo was transferred to the right uterine horn, pregnancy rates tended to be higher than when it was transferred to the left (81.3 % versus 65 %). Pregnancy rates did not differ according to the stage of development of the embryo; they were for morulae, tight morulae, blastocysts, and advanced blastocysts, respectively : 75.0 %, 66.7 %, 75.0 %, and 77.4 %

This study was performed to investigate the effect of gestation on the histological and histochemical changes of the uterine cervix of the native Korean cattle. A total of 110 cows obtained from the chonbuk abattoir were divided into six groups. The 1st group was of 9 non-pregnant cows and 101 singleton pregnant cows were grouped into 5 groups from pregnant I to pregnant V according to gestation periods by means of crown rump length measures. For light microscopy the tissues were fixed in 10% neutral formalin and processed routinely for paraffin sections. The 6um sections were taken and stained with H-E, Alcian blue pH 1.0, Alcian blue pH 2.5, Alcian blue pH 2.5/PAS, PAS reaction, toluidin blue, and trichrome. The cervical lengths and widths were increased in relation to advancing gestation. The cervical mucosubstance was composed of mixed mucopolysaccharides; the acid mucus was increased from the early pregnant state but the neutral mucus was found after pregnant IV, and the mucus was stained deeply in each staining in the fold cavity in according to gestation state.

The present study has been carried out to elucidate the antiestrogenic effects of tamoxifen in uteri of immature rats. Immature female Sprague-Dawley rats were allocated into 4 groups and injected with 5 micro g of estradiol-17 beta, 50 micro g of tamoxifen, a combination of both, or vehicle only subcutaneously three times after an interval of 24 hrs respectively