• Journal of Embryo Transfer
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• v.8 no.2
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• pp.105-109
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• 1993

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%).

• Journal of Animal Reproduction and Biotechnology
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• v.34 no.2
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• pp.111-116
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• 2019

This study was conducted to analyze the specific genes associated with sex-determination in Korean native cow. The highly organized spermatogenesis requires accurate spatial and temporal regulation of gene expression, which is governed by transcriptional, post-transcriptional, and epigenetic processes. Recently, farmers have been interested in determining the sexual identity of the calves in their farm. We analyzed the sperm of Korean native and Holstein cows, which were supplied from Hanwoo Improvement Center. We evaluated sperm motility and expression of sperm-specific genes after treating semen with both male- and female reagents. Sperm motility in Korean native cows decreased by approximately 10% in the first 30 minutes after treatment with sex-determination reagent. However, sperm motility of Holstein cows decreased to 60-70% after 15 minutes and to 20-30% after 30 minutes. We selected six specific genes expressing in the spermatozoa to analysis the gene expression level. The Real-time PCR results suggest that the selected genes (Gimap4, Tmeff1, Rac2, Abi2, Rac1, and Clu) were highly expressed in the group treated with the male reagent compared to the group treated the female reagent and to the untreated-group (control). In the present study, we suggest that the selected genes play a pivotal role in sex-determination.

• Journal of Embryo Transfer
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• v.13 no.2
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• pp.107-115
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• 1998

The present study was carried out for the comparative study on the collection of bovine follicular oocytes by ultrasound-guided ovum pick-up(OPU) and slaughterhouse-derived (SHD) ovary aspiration and in vitro production of bovine embryos with the follicular oncytes in Korean native cows. Bovine follicular nocytes were observed with a 6.5 MHz convex-array ultrasound transducer designed for intravaginal use and the oocytes were collected with the aspiration equipment attached to the ultrasonograph. Bovine ovaries were collected and transported in phosphate buffered saline from the local slaughterhouse, the follicular oocytes were collected by the aspiration method. The collected follicular oocytes in good quality were matured, fertilized and cultured in the media. The total number of the visible follicles and the recovery rate of follicular oocytes were increased in ultrasonography following follicle stimulating hormone(FSH) treatment in Korean native cows. The mean recovery rate of oocytes was 66.2, 52.8 and 41.7% in the FSH-OPU, non-treatment-OPU and SHD ovaries, respectively. The mean number of recorved oocytes per cow were not significantly(P<0.05) different between the FSH-OPU(14.0$\pm$11.54) and SHD(17.1i6.21) groups, but the numbers in both groups were significantly(P<0.05) higher than the number in the non-treatment-OPU(3.7$\pm$1.57) group. The mean number of usable nocytes in Grade T /11 per ovary was 6.3, 4.8 and 1.3 in the cows of the SHD, FSH-OPU and non-treatment-OPU groups, respectively. The in vitro developmental rate to the blastocyst was not significantly different between the oocytes obtained via OPU(37.1%) and SHD(29.3%). Therefore, the ultrasound-guided OPU technique can be applied to the production of excellent embryos from the high-quality cows, and for the large scale production of in vitro bovine oocytes and embryos, the SHD ovary aspiration method is valuable.

• Journal of Embryo Transfer
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• v.31 no.3
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• pp.273-279
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• 2016

The Korean native cattle, Hanwoo, is the most popular breed of beef cattle in Korea. However, the reproductive performance data are limited although reproduction is one of the most economically and biologically important in beef production. Therefore, this study was undertaken to investigate reproductive performance parameters including calving interval, parity for life time production. Data collected from 206,827 calvings were analyzed. There were no significant differences in calving interval and gestation days as parity increased from 2nd and 13rd parity cow, from spring to winter. However, we found a dramatic increase in calving interval after year 2000. About 1 month were increased per year ( y = 30.578x + 344.45 $R^2=0.9157$). Interestingly, we observed that parities for life time can be affected by birth weight. Calves with 23 kg at birth showed highest parities, $3.4{\pm}2.0$ times. In summary, this study provides valuable data on reproductive performance of Hanwoo and the data presented here can be used as a standard target for optimising and enhancing reproductive performance.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.10
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• pp.446-451
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• 2019

This study investigated the application of artificial insemination and pregnancy diagnosis kit for Korean native black goats. Semen was collected by electrical ejaculation, followed by semen analysis and artificial insemination in three goat strains (Dangjin, Jangsu and Tongyoung). Pregnancy was confirmed using a cow pregnancy test kit (IDEXX Rapid Visual Pregnancy Test kit) and ultrasound diagnosis. Analysis revealed that semen collected from male Korean native black goats by electrical ejaculation was about 1~1.5 ml in volume, $18{\sim}25{\times}10^8/ml$ concentration, and having > 97% motility. Furthermore, confirmation of pregnancy by pregnancy test kit and ultrasound diagnosis after artificial insemination were similar. In addition, the efficiency of pregnancy was 20~40% for all three strains: Tongyoung was the highest with 44%, followed by Dangjin (%), and Jangsu (20%). This study determines the artificial fertilization efficiency and the feasibility of using a cow pregnancy test kit for early pregnancy diagnosis in Korean native black goats. Although further research is required for validation, the results of the current study contribute to the breeding and improvement of Korean native black goat in research institutions as well as in general farms.

• Journal of Embryo Transfer
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• v.28 no.1
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• pp.13-18
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• 2013

The increase in the meat quality and milk production of cows, which breed Korean Native Cow (KNC) and Holstein cow, is not improving reproductive efficiency. In this study, we examined the effect of interferon (IFN) supplementation on motility of frozen-thawed semen and pregnancy rate after artificial insemination of KNC and Holstein cow. In experiment 1, we investigated the effect of IFN-tau concentration (10,000 IU and 20,000 IU) on the percentage of total motility (TM) and progressive motility (PM) of frozen-thawed spermatozoa. In experiment 2, KNC were infused 20,000 IU IFN-tau at insemination or after insemination. In experiment 3, KNC or Holstein cow were inseminated with frozen-thawed semen and infused 20,000 IU IFN-gamma or -tau after insemination. In experiment 1, the average of TM (23.9% to 30.9%) and PM (18.5% to 21.9%) were similar between control and treatments. In experiment 2, the pregnancy rates of IFN infusing times were not different from 45.8% to 53.6%. In experiment 3, the pregnancy rates of Holstein cow infused different kinds of IFN were similar (control, IFN-gamma, IFN-tau; 42.9%, 40.5%, 48.0%). In the case of KNC, however, the pregnancy rate of control was 55.6%, which was significantly lower than that of IFN-gamma (68.9%; p<0.05). Thus, IFN is effective on the improvement of reproductive efficiency, but further study is needed.

• Journal of the Korea Organic Resources Recycling Association
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• v.10 no.4
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• pp.96-102
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• 2002

The purpose of this study was estimate the optimal phosphorus and calcium levels of Korean native cow manure on the growth and cast production of earthworm(Eisenia foetida). Phosphorus and calcium levels supplemented to cow manure were 0%(without earthworm), 2% and 4%, and 0.01%, 0.02%, 0.04% and 0.06% of the cow manure by weight, respectively. The maximum fresh weight and increasing rate of earthworm were obtained with 2% phosphorus level, but there was not significant differences between calcium levels. The ratios of available phosphorus to calcium contents of cast were 1.04-1.20:1 with 2%, and 1.28-1.37:1 with 4% phosphorus levels. Conversion rate of organic matter to earthworm tissue were 0.35-0.41% with 2%, and 0.25-0.40% with 4% phosphorus levels.

• Korean Journal of Veterinary Research
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• v.27 no.2
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• pp.321-330
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• 1987

In the endemic area of bovine piroplasmosis in Chonbuk Province, total of 486 heads of Holstein cow selected from 14 farms randomly were examined the infection status of piroplasma and their blood values. The results obtained were summarized as follows: 1. The etiological agent was only Theileria sergenti and none of the Babesia sp. infection. 2. All of the 486 heads of examined cow were infected with Theileria sergenti (100%). 3. In the initial examination of 11 farms in early summer, the means of blood values were as follows; RBC:$526{\pm}84(10^4/mm^3$), Ht:$27.9{\pm}2.8%$, SP:$7.5{\pm}0.6g/dl$, WBC: $11586{\pm}354/mm^3$, and Fibrinogen: $578.5{\pm}164.1mg/dl$. 4. In the second examinations in slimmer season, the blood values of examined cows had little varieties. But in the winter season, cows housed in the barn, the blood values were greatly increased; RBC: $601{\pm}77(10^4/mm^3)$, (F-value: 37.186**), Ht: $30.5{\pm}1.3%$(F-value: 15.626**) Hb: $12.2{\pm}1.3g/dl$(F-value: 5.899**), SP: $7.4{\pm}0.6g/dl$(F-value: 5.05**). 5. To determine the piroplasma infection in the many herds of cow, the measurement of Ht, Hb, and SP values etc. were more effective and helpful to find the weak cow because the examined process are not only to be easily carry out many samples but also to be done very simple and rapidly. 6. The indications of therapeutic standard values were stablished as follows; the less than 20% in the Ht value, below the 10g/dl in the Hb value, and less than 6g/dl in SP value. When the one among the therapeutic standard values, Ht, Hb, and SP was below the therapeutic standard value, the cow was treated with nutriments. When more than two among them were below the therapeutic standard, the cow was treated with Berenil, at once. In this way, there was no one head which represented clinical signs of piroplasmosis among 486 heads of cow at 14 farms during the year of 1986. 7. In a Korean native cattle infected with Thieleria sergenti seriously, the recovery of blood values was very prolonged by the treatment of Berenil only. But by the transfusion of 300ml blood collected from normal cow, the blood values were recovered rapidly.

• Journal of the korean veterinary medical association
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• v.16 no.1
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• pp.29-34
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• 1980

The latent infection of Toxoplasma in swine, Holstein cow and Korean native cattle raised in Jeonnam prefacture during 1978 was proved serologically. Of the 127 swine, 73($57.4\%$) cases were positive for the indirect hemagglutination test, and

• Korean Journal of Animal Reproduction
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• v.12 no.1
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• pp.20-23
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• 1988

The 3211 Korean native cows raised in Muan, Milyang were investigated for the purpose of finding reproductive rate of cows that retained fetal membrane for two years from April, 1981 to March, 1983. The results obtained were summarized as follows ; 1. The incidence of retained fetal membrane was found in 64 cows(1.98%). 2. The day to first estrus was similar to normal postpartum period unless concurrent genital infection occured. 3. Conception rate of cows that retained fetal membrane was 32.7%, 10.9%, 5.2% and 3.6% at the first, second, third and forth service, respectively and non pregnant cow was 47.6%. 4. Reproductive disorder of non pregnant cows was the highest in repeat breeder and the effect of treatment was very low.