• Reproductive and Developmental Biology
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• v.32 no.3
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• pp.175-181
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• 2008

This study was conducted to investigate an effective recipient oocyte and culture system for producing of Hanwoo (Korean native cattle) somatic cell nuclear transfer (SCNT) embryos. Hanwoo ear skin fibroblasts were used as donor cells. In vitro matured Hanwoo or Holstein oocytes were enucleated, and single donor cells were transferred into the perivitelline space of the enucleated oocytes. The couplets were subsequently fused and activated. The reconstructed embryos were cultured in a conventional or sequential culture system. In the former, embryos were cultured in CR2aa medium for eight days; in the latter, embryos were cultured in modified CR2aa-A (mCR2-A) for three days and then further cultured in modified CR2aa-B (mCR2-B) for five days. In the experiment with the recipient oocyte, the rate of embryo development to the blastocyst stage was significantly (p<0.05) higher in Hanwoo recipient oocytes than in Holstein ones (48.8% vs 38.9%). BIastocysts derived from Hanwoo recipient oocytes contained significantly (p<0.05) higher numbers of total cells than those derived from Holstein recipient oocytes ($156.0{\pm}68.2$ vs $134.7{\pm}54.8$). There was no difference in the mean proportion of apoptotic cells in blastocysts between the sources of recipient oocytes. In the experiment with the embryo culture system, the blastocyst rate was somewhat higher in sequential system than in conventional system (50.0% vs 43.5%), though there was no significant difference. The numbers of total ($160.0{\pm}69.0$ vs $156.7{\pm}68.4$) and apoptotic cells ($14.0{\pm}10.4$ vs $11.8{\pm}6.4$) were not different between the culture systems. In conclusion, the present study demonstrated that Hanwoo recipient oocytes and the sequential culture system were more effective in supporting the production of Hanwoo SCNT embryos.

• Genomics & Informatics
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• v.14 no.4
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• pp.230-233
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• 2016

Linkage disequilibrium (LD) is the non-random association between the loci and it could give us a preliminary insight into the genetic history of the population. In the present study LD patterns and effective population size (Ne) of three Korean cattle breeds along with Chinese, Japanese and Mongolian cattle were compared using the bovine Illumina SNP50 panel. The effective population size (Ne) is the number of breeding individuals in a population and is particularly important as it determines the rate at which genetic variation is lost. The genotype data in our study comprised a total of 129 samples, varying from 4 to 39 samples. After quality control there were ~29,000 single nucleotide polymorphisms (SNPs) for which $r^2$ value was calculated. Average distance between SNP pairs was 1.14 Mb across all breeds. Average $r^2$ between adjacent SNP pairs ranged between was 0.1 for Yanbian to 0.3 for Qinchuan. Effective population size of the breeds based on $r^2$ varied from 16 in Hainan to 226 in Yanbian. Amongst the Korean native breeds effective population size of Brindle Hanwoo was the least with Ne = 59 and Brown Hanwoo was the highest with Ne = 83. The effective population size of the Korean cattle breeds has been decreasing alarmingly over the past generations. We suggest appropriate measures to be taken to prevent these local breeds in their native tracts.

• Asian-Australasian Journal of Animal Sciences
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• v.16 no.2
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• pp.176-179
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• 2003

Insulin-like growth factor-I (IGF-I) is a polypeptide that has the function of regulating the expression of steroid hormones through endocrine, paracrine, and autocrine actions in reproductive organs. Moreover, IGF-I is involved in ovulation, implantation, maintenance of pregnancy, and development of fetuses in animals. Therefore, this study was conducted to investigate the effects of serum IGF-I concentration on progesterone ($P_4$) concentration and pregnancy rates in Korean native cattle (Hanwoo). Blood was collected at estrus (Day 0) and Day 11. Artificial insemination was performed at Day 0. Serum IGF-I and $P_4$ concentrations were measured by radioimmunoassay (RIA). Overall, $P_4$ concentration was higher at Day 11 than Day 0, whereas the pattern of IGF-I concentration was reversed. When animals were divided into two groups depending on the pregnancy status, $P_4$ concentrations of the pregnant group was significantly higher than that of the non-pregnant group at Day 0 (p<0.05) and Day 11 (p<0.05). But, lower IGF-I concentrations were detected in the pregnant group at Day 0 (p<0.05) and Day 11 (p<0.05) compared to the non-pregnant group. In conclusion, these results indicated that serum IGF-I is inversely associated with $P_4$ concentration during early pregnancy in Hanwoo.

• Journal of Embryo Transfer
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• v.31 no.3
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• pp.261-265
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• 2016

The aim of the present study was to evaluate and estimate timing of artificial insemination (AI) in Hanwoo heifer (Korean native cattle) that is the most popular breed of beef cattle in Korea. To determine changes in body weight of heifers around AI, body weight were measured at different stages either before or after AI. We found that daily body weight gain was higher in the pregnant cows after AI. We also investigate correlation between body mass measured by shoulder height and body length, and conception rates, used (body length+ height)2 instead of height2 for body mass index (BMI), and found that relatively more BMI heifers (>55) showed higher conception rates. Finally, we estimated body weight by measuring should height (SH), heart girth (HG), and body length (BL); $BW=3.93372^*HG-2.90985^*SH-0.021^*BL$. In addition, we observed that HG is most closely correlated with BW; $y(BW)=1.77355^*x(HG)$, $R^2=0.98881$. In summary, we can determine the best timing of AI using body measurement and its application including BMI.

• Asian-Australasian Journal of Animal Sciences
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• v.30 no.1
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• pp.8-19
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• 2017

Objective: A whole genome association study was conducted to identify single nucleotide polymorphisms (SNPs) with additive and dominant effects for growth and carcass traits in Korean native cattle, Hanwoo. Methods: The data set comprised 61 sires and their 486 Hanwoo steers that were born between spring of 2005 and fall of 2007. The steers were genotyped with the 35,968 SNPs that were embedded in the Illumina bovine SNP 50K beadchip and six growth and carcass quality traits were measured for the steers. A series of lack-of-fit tests between the models was applied to classify gene expression pattern as additive or dominant. Results: A total of 18 (0), 15 (3), 12 (8), 15 (18), 11 (7), and 21 (1) SNPs were detected at the 5% chromosome (genome) - wise level for weaning weight (WWT), yearling weight (YWT), carcass weight (CWT), backfat thickness (BFT), longissimus dorsi muscle area (LMA) and marbling score, respectively. Among the significant 129 SNPs, 56 SNPs had additive effects, 20 SNPs dominance effects, and 53 SNPs both additive and dominance effects, suggesting that dominance inheritance mode be considered in genetic improvement for growth and carcass quality in Hanwoo. The significant SNPs were located at 33 quantitative trait locus (QTL) regions on 18 Bos Taurus chromosomes (i.e. BTA 3, 4, 5, 6, 7, 9, 11, 12, 13, 14, 16, 17, 18, 20, 23, 26, 28, and 29) were detected. There is strong evidence that BTA14 is the key chromosome affecting CWT. Also, BTA20 is the key chromosome for almost all traits measured (WWT, YWT, LMA). Conclusion: The application of various additive and dominance SNP models enabled better characterization of SNP inheritance mode for growth and carcass quality traits in Hanwoo, and many of the detected SNPs or QTL had dominance effects, suggesting that dominance be considered for the whole-genome SNPs data and implementation of successive molecular breeding schemes in Hanwoo.

• Journal of Animal Reproduction and Biotechnology
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• v.36 no.2
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• pp.106-115
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• 2021

Sperm cryopreservation is an important method of assisted reproductive techniques and storing genetic resources. It plays a vital role in genetic improvement, livestock industrial preservation of endangered species, and clinical practice. Consequently, the cryopreservation technique is well organized through various studies, especially on Korean native cattle (Hanwoo). However, the cryopreservation technique of Korean native brindled cattle, which is one of the native cattle species in Korea, is not well organized. Therefore, it is necessary to develop a Supplementary Table technique for the cryopreservation of Korean native brindled cattle. For this purpose, it is important to first evaluate the quality of the currently produced cryopreserved sperm of Korean native brindled cattle. In this study, we randomly selected 72 individual Korean native brindled cattle semen samples collected from 8 different region research centers and used them to evaluate sperm functions. We focused on the quality evaluation of cryopreserved Korean native brindled cattle semen following the measurement of motion kinematics, capacitation status, intracellular ATP level, sperm motility, and cell viability. Then, the values of each of the eight groups were derived from various sperm parameters of nine individual samples, including sperm motility, kinematics, cellular motility, and intracellular ATP levels, which were used to compare and evaluate sperm function. Overall, differences in various sperm parameters were observed between most of the research centers. Particularly, the deviations of motility and motion kinematics were high according to the sample. Therefore, we suggest that it is necessary to develop a standard method for the cryopreservation of Korean native brindled cattle semen. We also suggest the need for sperm quality evaluation of the cryopreserved semen of Korean native brindled cattle before using artificial insemination to attain a high fertility rate.

• Korean Journal of Veterinary Service
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• v.39 no.4
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• pp.221-226
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• 2016

The animal welfare issues in cattle breeding include breeding environment, elimination, and castration. Among these, castration is unavoidable because it decreases cattle aggressiveness, improves meat quality, and enhances feed efficiency. In this study, the degree of stress associated with various methods of castration treatment was investigated for animal welfare in Hanwoo breeding. Cortisol levels dramatically increased right after castration in both the SoF and SoV groups. However, the increase in the SoF group was significantly (P<0.05) higher than that in the SoV group, and the range of decrease was also smaller. Among the behavioral characteristics, standing was significantly (P<0.05) higher in the SoV ($374.93{\pm}21.51$) and SoF ($379.93{\pm}21.30$) groups based on the behavioral time (min/12 hours) compared to that in the NC group ($359.37{\pm}19.69$). The SoF and SoV groups did not show any significant (P<0.05) difference. In terms of behavioral frequency, the NC group demonstrated a significantly (P<0.05) high frequency of drinking, self-grooming, scratching, and rubbing, and a significantly (P<0.05) less frequency of fighting behavior. The feeding time significantly (P<0.05) decreased in the SoV and SoF groups, and their frequencies of pairwise grooming were significantly (P<0.05) less. Based on the results, the cattle experienced less stress during castration by a veterinarian than during treatment using a move-stop.

• Korean Journal of Veterinary Service
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• v.42 no.2
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• pp.113-116
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• 2019

Bovine theileriosis caused by Theileria sergenti is a tick-borne hematoprotozoan disease that is characterized by chronic anemia and fever in cattle. In this study, results of microscopic examination and PCR detection confirmed 17 Korean native cattle with emaciation and fever as acute bovine theileriosis caused by T. sergenti. Buparvaquone was injected as treatment, but was proved to be an inappropriate measure according to our study. After 6 months of injection, clinical signs and hematological values were recovered, but T. sergenti was still identified in blood sample as a result of microscopic exam and PCR. These results suggest that continuous management is necessary to control bovine theileriosis. Therefore, findings of this study may provide significant guideline on the control of bovine theileriosis.

• Journal of Veterinary Clinics
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• v.33 no.6
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• pp.346-350
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• 2016

Two 1-year old calves of Korean Native cattle (Hanwoo) presented cutaneous papillomas on the face and neck. Type 2 bovine papillomavirus (BPV-2) was identified in the cutaneous papillomas based on BPV-specific PCR and subsequent DNA sequencing analysis results. Using DNA samples extracted from two affected calves and unaffected animals reared in the same stable, BPV-2 was not only detected in the cutaneous papillomas of affected animals based on BPV-specific PCR analysis, but also detected in normal skins, hairs, and their environments based on nested PCR analysis. BPV-2 was also detected in DNA samples isolated from animals and environments of that distinct stable with affected calves. However, no BPV-2 was detected in the drinking water of both stables (infected and unaffected). These findings concluded that BPV-2 was transmitted by direct or indirect contact, not by drinking water. This is the first report to show molecular evidence of BPV-2 infection. Rapid and precise molecular identification can be used to screen BPV-2 in cattle farms to understand the biological roles of BPV in animal diseases.

• Korean Journal of Animal Reproduction
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• v.19 no.3
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• pp.197-203
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• 1995

Serum progesterone concentrations of pregnant and non-pregnant Hanwoo were compared to evaluate the possibility of early pregnancy prediction. Twenty five female Hanwoo were devided into two groups. Eighteen heads were injected with 980$\mu\textrm{g}$ tiaprost trometamol salt(Iliren:PGF2$\alpha$ analogue) for estrous synchronization and fifteen heads of them were inseminated artifically and seven heads were non-treated. Blood samples were collected from the jugular vein before PGF2$\alpha$ injection and on day 0, 18, 21 after estrous induction. Pregnancy of cattle was confirmed by rectal palpaton after 60 days of artificial insemination. The serum progesterone concentrations at heat showed no significant differences between pregnant and non-pregnant while on day 18 and 21 after estrous induction showed significant differences(p<0.05). The accuracy of pregnancy diagnosis on day 18 and 21 after estrous induction was 85.7 and 71.4% respectively while that of non-pregnancy were 71.4 and 100.0% respectively.