• 대한수의학회지
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• 제17권2호
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• pp.41-49
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• 1977

The present study was underve the histochemical nature of various follicles and interstitial tissues in the ovaries of Korean native goats and cattle as well as the histochemical changes of those in the ovaries of Korean native goats treated with dexamethasone. Much more lipid granules appeared in the granulosa and theca cells of atretic follicles compared with normal follicles in these ruminant ovaries. In the ovaries of Korean native goats the interstitial tissue derived from the theca interna of atretic follicles appeared the form of patches of cells and the interstitial tissue derived from stromal cells appeared the form of diffuse, obscure bounds. In the ovaries of Korean native cattle the interstitial tissue derived from theca interna of atretic follicles showed sparsely scattered form of pathes of cells. The histochemical components were described on the basis of lipids in the granulosa and theca cells of normal follicles, atretic follicles and interstitial tissue. In the ovaries of Korean natve goats treated with dexamethasone, the granulosa and theca cells of atretic foillicle contained plenty lipid granules that were increased in size and number, however, lipid granules were markedly decreased in the interstitial tissue.

• 대한수의학회지
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• 제17권1호
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• pp.5-8
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• 1977

One hundred and fifty seven Escherichia coli strains isolated from 18 cattle (9 dairy cattle received penicillin, streptomycin (SM) or sulfadimethoxine for treatment of diseases and 9 Korean native cattle not received antibiotics) were studied for the drug resistance and distribution of R factors. Of 88 E. coli strains isolated from cattle not received antibiotics, only 1 strain was resistant to SM, but about 46 per cent of 69 E. coli strains isolated from cattle received antibiotics were resistant to SM, tetracycline (TC), ampicillin (AP), kanamycin (KM), chloramphenicol (CM), and sulfisomidine (Su), alone or in combination thereof. Of resistant strains, about 72% were resistant to three or more antibiotics, but 28% were found to singly resistant. The most frequent resistant pattern was triple resistance to AP, KM and Su (37.6%), and quadruple one to SM, TC, CM and Su (12.5%). About 28% of resistant strains carried R factors which were transferable to E. coli ML 1410 $NA^r$ by conjugation.

• 농업과학연구
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• 제45권3호
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• pp.493-498
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• 2018

There has been widespread warming and a general increase in summer temperatures over the Korean peninsula ($0.5^{\circ}C$/10 years from 2001 to 2010). South Korea is transforming into a subtropical region, and the productivity of livestock is affected by the climatic changes. In this study, we investigated whether the summer heat waves affect the developmental competency of Korean native cattle (Hanwoo), a taurine type of cattle with a small portion of indicine varieties. We collected oocytes during the summer (heat stress, HS) and autumn (non-HS condition) and examined the developmental competencies including in vitro maturation and preimplantation embryo development. No significant differences were observed between the HS and non-HS oocytes in nuclear maturation (extrusion of the polar body); however, the cleavage and blastocyst rates were significantly lower in the HS group than those in the non-HS group. The lower developmental competence of the HS oocytes compared to the non-HS is, in part, due to insufficient cytoplasmic maturation because of a higher production of Reactive oxygen species (ROS) levels as well as peri/cortical distributed mitochondria in the HS oocytes after in vitro maturation. Next, we examined the ROS and mitochondria distribution and found a significant increase in the levels of ROS in the HS oocytes and a polarized distribution (pericortical cytoplasm) of mitochondria in the HS oocytes. In summary, impaired cytoplasmic maturation of oocytes from exposure to HS affects the preimplantation embryo development by dysfunction of mitochondria. To improve reproductive performance, embryo transfer using cryopreserved embryos/oocytes is recommended in the hot summer season of South Korea.

• 한국동물위생학회지
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• 제14권2호
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• pp.154-158
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• 1991

To investigate the Akabane antibody in the cattle with the serological test in Chung Chung Buk Do from May to Nov 1191. The result are summarized as follows. 1. Breed in cattle reacted as positive condition in Akabane antibody 76 heads(42%) in 180 cattles reacted as positive condition in Akabane antibody, 23 heads(51%) in 45 Korea native cattle reacted as positive condition in Akabane antibody. 2. During 5, 9, 10, 11 month, Akabane antibody in cattle is over 45%. 3. Less of 2 years old and over 4 years old cattle are Akabane antibody in cattle is over 40%. 4. The relation of titer of 2 folds of dilution HA and 10 folds of dilution TCID$_{50}$ was same relation.n.

• Asian-Australasian Journal of Animal Sciences
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• 제33권5호
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• pp.742-752
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• 2020

Objective: This study investigated the effects of vitamin A (VA) supplementation during late-stage pregnancy on longissimus dorsi muscle tissue development, birth traits, and growth performance of postnatal Korean native calves. Methods: In the preliminary experiment, twenty-six pregnant cattle (initial body weight [BW] = 319 kg (standard deviation [SD] = 30.1; 1st parity) were randomly assigned to the control and treatment groups. The treatment group received VA supplementation at 24,000 IU/d from gestational day 225 until delivery. In the main experiment, twelve pregnant cattle (initial BW = 317 kg [SD = 31.3]; 1st parity) were treated with VA supplementation at 24,000 IU/d (gestational days 150 to 225) and at 78,000 IU/d (gestational day 225 until delivery). Serum VA levels were analyzed in pregnant cattle, and the growth performance, gene expression, and serum VA levels were analyzed in the offspring. Results: Serum VA levels in pregnant cattle decreased the late gestation in both experiments (p<0.001). In the main experiment, pregnant cattle at parturition and offspring at birth in the treatment group had higher serum VA levels than those in the control group (p<0.05). In the treatment groups, an increased birth weight was observed in the main experimental group (p = 0.022), and a tendency (p = 0.088) toward an increased birth weight was observed in the preliminary experimental group. However, no differences were observed in the feed intake, average daily gain, gain-to-feed ratio, or BW of 31-day-old calves. Gene expression was analyzed in longissimus dorsi muscles of 31-day-old calves. VA supplementation in pregnant cattle stimulated postnatal muscle development in offspring by elevating myogenic factor 5 (MYF5), MYF6, and myoblast determination levels (p<0.05). Moreover, preadipocyte-related marker genes such as extracellular signal-regulated kinase 2 and krüppel-like factor 2 were higher in the treatment group than in the control group (p<0.05). Conclusion: VA supplementation (78,000 IU/d) in late-stage pregnant cattle maintained serum VA levels. In addition, 78,000 IU/d VA supplementation increased the birth weight and expression of genes related to muscle and preadipocyte development in offspring. Overall, 78,000 IU/d VA supplementation in pregnant cattle is beneficial to newborn calves.

• 농업과학연구
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• 제25권1호
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• pp.79-88
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• 1998

본 연구는 축협중앙회 한우개량부에서 사육중인 한우의 혈액으로부터 genomic DNA를 추출하여 한우의 면역체계에 중요한 역할을 담당하고 있는 BoLA DRB3 exon2 유전자를 PCR기법을 이용하여 증폭하고 친자확인을 위한 이들 대립유전자들의 염기서열을 분석하여 한우의 효율적인 육종에 분자유전수준에서의 접목을 위한 기초자료를 얻고자 실시하였던바, 얻어진 결과를 요약하면 다음과 같다. 1 한우의 혈액에서 추출된 genomic DNA를 1.5% agarose gel에서 전기영동한 결과, 12.2kb이상의 단일밴드로 나타나, genomic DNA는 아주 잘 분리된 것으로 판단되었으며, 한편 genomic DNA로부터 PCR기법을 이용하여 BoLA DRB3 exon2 유전자를 증폭한 결과 284kb의 단편이 증폭 되었음을 확인하였다. 2. PCR 증폭산물을 pCR 2.1 vector를 사용하여 cloning 하고, 균주에 형질전환을 시켜 재조합 plasmid를 추출한 후, EcoR 1으로 처리한 결과 300bp 단편이 확인되어 증폭되어진 BoLA DRB3 exon2 유전자가 vector 내에 잘 삽입되었음을 확인하였다. 3. 부와 모의 BoLA DRB3 exon2 대립유전자의 염기서열을 분석한 결과 염기서열의 상동성은 부의 대립유전자간에는 82.0% 이었고, 모의 대립유전자간에는 90.1%이었다. 4. 친자를 확인하기 위해 부와 모 그리고 자손간의 가계에 대한 BoLA DRB3 exon2 대립유전자의 염기서열을 분석한 결과 Mendel 의 법칙에 따라 유전된다는 사실을 확인 할 수 있었다. 5. 이상의 결과를 종합하여보면 한우의 BoLA DRB3 exon2 유전자의 부와 모, 그리고 자손의 대립유전자에 대한 염기서열 수준에서의 친자확인이 가능하였으며, 이들 연구결과는 축우의 유전적 능력개량에 중요한 분자유전학적 기초 자료가 될 것으로 판단되었다.

• 농업과학연구
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• 제47권3호
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• pp.667-672
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• 2020

It is well known that intensive selection caused a decline in reproductive performance in dairy cattle. Interestingly, the reproductive performances including fertility and calving interval of Korean native beef cattle have declined in the last 20 years, suggesting that a breeding program focusing on carcass weight and intramuscular fat may affect the reproductive physiology in Korean native beef cattle, too. In this study, we analyzed the calving interval (CI) and selection index (SI) based on genome-wide association studies (GWAS) of Hanwoo cows for seven years (2013 - 2019). Multiparous cows (4.5 ± 0.11) were analyzed, which were bred by artificial insemination (AI). We first examined the distribution of the AIs and calving dates. About 40% of the AIs were carried out in May to June and October to December; subsequently, calving was observed from March to April and August to October, respectively, indicating the cows were seasonally bred. No correlation between CI and SI was found (y = 0.0459x - 17.64; R² = 0.0356), but the ratio of cows with a positive SI was higher in the longer CI group compared to the shorter group, suggesting that the selection for meat quality and quantity may affect the reproductive performances. In addition, the average value of SI was - 3.42 in the CI < 400 while + 5.79 in the CI > 400 although the values were not statistically significant. However, our results suggest that reproductive indices such as fertility and CI should be considered for sustainability in the Hanwoo breeding selection program.

• 대한수의학회지
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• 제43권4호
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• pp.667-675
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• 2003

The safety of Brucella abortus strain RB51(SRB51) was investigated in dairy cows and Korean native cattle of 4~7th month of gestation. From experimentally inoculated cattle, 18 of 25 (72.0%) dairy cows, and 3 of 10 (30.0%) Korean native cattle were aborted or delivered premature fetus. There were no significant differences in the incidence of abortion depending on the inoculation route (intramuscular and subcutaneous) and dosages ($1{\times}10^9$, $2.8{\times}10^9$, and $4.0{\times}10^9$ CFU). The antibodies to the SRB51 were measured by a dot blot enzyme-linked immunosorbent assay. The highest titers to SRB51 were detected between 5~7 weeks after inoculation and the specitic antibody could be detected up to 28 weeks after inoculation. The SRB51 was isolated from amnio-allantoic fluid, bronchial lymph node, mammary gland, and supramammary lymph node in 5 of 25 dairy cows during 4 weeks after either abortion or delivery. Although SRB51 was isolated from 4 of 24 aborted fetus or normally delivered calves at parturition time, it was not isolated during 4 weeks afterward. Eleven of twentyfive dairy cows showed the endometritis and/or necrosis until 6 weeks after delivery, no lesions were seen at 8 weeks after delivery and uterus from control dairy cows. The results of present study revealed that SRB51 might induce the clinical signs of brucellosis in the pregnant cattle at 4~7th month of gestation.

• 한국축산시설환경학회지
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• 제2권2호
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• pp.155-164
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• 1996

The objective of this study was to estimate the investment limit in equipment capital by Capital Recovery Method. The data used was collected from 23 Hanwoo(Korean Native Cattle) farms in 1994. The necessary time for herd size expansion was average 5 years from opening(9.7 heads) to 50 heads, 4 years from 50 to 100heads, 3 years from 100 to 150 heads, and 2 years from 150 to 200 heads, respectively. It took 14 years from opening to 200 heads of herd size. The debts for fattening cattle farms were 15.2million won for the size of 50 heads, 37.1 million won for the size of 100 heads and 89.0 million won for the size 200 heads, respectively. Average rates of debt interest were 5.1 % 7.2 and 10.8, correspendingly. As the hear size increased, debt interest rates also increased due to government funds limit. The investment limits in equipment capital perfarm household were 77.7 million won for 50 heads, 135.1 for 100 heads, and 294.3 for 200 heads for 5,500 won per kg liveweight, 70.7 million won for 50 heads, 122.6 for 100 heads and 269.3 for 200 heads for 5,000 won per kg liveweight, 63.6 million won for 50 heads 110.0 for 100 heads and 244.2 for 200 heads for 4,500 won per kg liveweight.

• 한국동물위생학회지
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• 제32권2호
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• pp.171-176
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• 2009

Johne's disease is a chronic inflammatory bowel disease of cattle, sheep, goats and other ruminants, and Mycobacterium paratuberculosis is the etiologic agent of this disease. Many studies have been carried out on paratuberculosis from daily cattle and Korean native cattle in multiple areas around nation, but there is no report in Eastern-Gyeongbuk area. The purpose of this study is to investigate the seroprevalence of bovine paratuberculosis in Eastern-Gyeongbuk area. From July to December in 2007, blood samples were collected from 363 dairy cattle of 27 farms and 281 Korean cattle of 114 farms and the ELISA was conducted. 25 (6.9%) dairy cattle of 6 (22%) farms and 19 (6.8%) Korean cattle of 8 (7.0%) farms were positive in ELISA. In regional analysis, 25 (8.3%) out of 300 dairy cattle in Gyeungju were positive and Pohang were negative in this research. 12 (16.4%) out of 73 Korean cattle in Gyeungju and 7 (9.6%) out of 73 Korean cattle in Uljin were positive. Pohang and Youngdeok of Korean cattle were negative in this research. According to raising scale of dairy cattle, 4 (66.7%) farms out of 6 farms were raising 30 below and 2 (33.3%) farms out of were raising 30$\sim$70. And there were negative raising scale more than 70. In Korean cattle, 6 (75%) farms out of 8 were raising below 10 and 2 (25%) farms were raising 10$\sim$30. And there were negative raising scale more than 30. The rate of seropositive of paratuberculosis dairy cattle and Korean cattle were similar and the positive rate of Eastern-Gyeongbuk area is reported lower than that of any other region.