• 생명과학회지
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• 제21권4호
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• pp.494-501
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• 2011

소의 Extension (E), Agouti (A) 유전자형과 모색유전양상의 연관관계를 이해하기 위해, 한우와 제주흑우(JBC), 이들 사이에서 생산된 교배후손에서 melanocortin-1 receptor (MC1R)과 agouti signaling protein (ASIP)의 유전자형을 분석하였다. 흑모색의 JBC에서는 세 가지 MC1R 대립인자들($E^D$, $E^+$, e)이 모두 발견되었다. JBC 집단은 한우에서 우점적으로 나타나는 열성동형접합자(e/e)가 발견되지 않았다. 반면, MC1R $E^+$/e 한우는 흑모색이 아닌 갈색이나 적색의 모색을 나타내었다. ASIP 유전자에서, 한우에서는 L1-BT 전위인자의 삽입/결실에 의해 세 가지 유전자형(A/A, A/$A^{Br}$, $A^{Br}/A^{Br}$)이 모두 관찰되었다. JBC 집단에서는 ASIP $A^{Br}$ 대립인자가 드물게 관찰되고, ASIP $A^{Br}/A^{Br}$ 동형접합인 개체들은 발견되지 않았다. ASIP $A^{Br}$ 대립인자를 보유하더라도 한우와 JBC, 이들의 교배후손에서도 agouti-유사 얼룩무늬 모색은 발견되지 않았다. 교배후손의 모색은 Agouti 유전자형과는 무관하고, Extension 유전자형과 직접적으로 연관되어 황-갈색(e/e)과 암-갈/흑색($E^+$/e)으로만 구분되었다. ASIP 유전자형은 아마도 한우 또는 교배 후손에서 모색의 발달에 영향이 없는 것으로 추정된다. 본 연구 결과는 한우, 제주흑우, 이들의 교배후손에서 MC1R 유전자형이 모색 표현형을 결정하며, ASIP 유전자형은 모색의 변이에는 핵심적인 역할을 수행하지 않는다는 것을 시사한다.

• 한국동물위생학회지
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• 제30권2호
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• pp.275-281
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• 2007

Neospora caninum (N caninum) is an intracellular protozoa parasite, and its infection is one of the important diseases because it can cause abortion in cattle. This study was conduct to gain epidemiological data for more effective control of the disease. Bloods were collected from 2,162 cattle on 90 farms from February to September 2006. Serums were tested for antibodies to N caninum using ELISA CherdCheck, IDEXX). The dairy breed presented a higher proportion of seropositive results than that of Hanwoo. The estimated proportion of N caninum-positive dairy farms was 71.1 %, but the overall seroprevalence was estimated as 22.8%. The seroprevalence of dairy cattle and Hanwoo were 31.0% and 4.9%, respectively. There was no significant difference in the seroprevalence by age, but the not-intensive managed farms had a high seroprevalence (OR=1.91, p-value<0.01). The antibody rate of cattle with dog(s) was greater than that of those without dogs (OR=2.13, p-value<0.01). There was a significant difference in abortion rate between seropositive cattle and seronegative ones (OR=6.2, p-value<0.01).

• 한국동물위생학회지
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• 제42권2호
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• pp.61-65
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• 2019

Seroprevalence of Coxiella burnetii (Q fever) in bulk-tank milk and cattle in Daegu area was analyzed from 2017 to 2018 by ELISA. The prevalence of antibodies in collected bulk-tank milk from 12 dairy cattle farms was 41.7% (10/24) and the seroprevalence of 249 cows reared in the area of Daegu was 3.2% (8/249) By age, the seroprevalence was 1.9% (2/105) in less than 2 years of age, 4.2% (5/119) between 3 and 5 years of age and 4.0% (1/25) in more than 6 years of age. By breed, the seroprevalence of the Hanwoo cattle was 1.2% (2/162) and the seroprevalence of the dairy cattle was 6.9% (6/87). The result suggested that seroprevalence of C. burnetii was relatively high in both bulk-tank milk samples and dairy cattle than the Hanwoo cattle. Based on these data, it is necessary to keep monitoring the prevalence of Q fever in Daegu area.

• Asian-Australasian Journal of Animal Sciences
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• 제31권11호
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• pp.1691-1699
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• 2018

Objective: In Korea, there are three main cattle breeds, which are distinguished by coat color: Brown Hanwoo (BH), Brindle Hanwoo (BRH), and Jeju Black (JB). In this study, we sought to compare the genetic diversity and divergence among there Korean cattle breeds using a BovineHD chip genotyping array. Methods: Sample data were collected from 168 cattle in three populations of BH (48 cattle), BRH (96 cattle), and JB (24 cattle). The single-nucleotide polymorphism (SNP) genotyping was performed using the Illumina BovineHD SNP 777K Bead chip. Results: Heterozygosity, used as a measure of within-breed genetic diversity, was higher in BH (0.293) and BRH (0.296) than in JB (0.266). Linkage disequilibrium decay was more rapid in BH and BRH than in JB, reaching an average $r^2$ value of 0.2 before 26 kb in BH and BRH, whereas the corresponding value was reached before 32 kb in JB. Intra-population, interpopulation, and Fst analyses were used to identify candidate signatures of positive selection in the genome of a domestic Korean cattle population and 48, 11, and 11 loci were detected in the genomic region of the BRH breed, respectively. A Neighbor-Joining phylogenetic tree showed two main groups: a group comprising BH and BRH on one side and a group containing JB on the other. The runs of homozygosity analysis between Korean breeds indicated that the BRH and JB breeds have high inbreeding within breeds compared with BH. An analysis of differentiation based on a high-density SNP chip showed differences between Korean cattle breeds and the closeness of breeds corresponding to the geographic regions where they are evolving. Conclusion: Our results indicate that although the Korean cattle breeds have common features, they also show reliable breed diversity.

• Journal of Animal Science and Technology
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• 제50권5호
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• pp.633-640
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• 2008

소의 모색 발현에 결정적인 역할을 수행하며 Extension 좌위에 암호화되어 있는 melanocortin- 1 receptor(MC1R) 유전자형을 변형된 염기서열이 증폭되게 제작된 이중 mismatch primer 쌍을 이용하여 PCR-RFLP 방법으로 분석하였다. 증폭된 PCR 절편들은 MC1R 유전자에서 모색 표현형과 직접적으로 연관되어 있어 중요하게 다루어지고 있는 세 가지 대립인자들(ED, E+, e)로 MspI-과 AluI-RFLP에 의해 성공적으로 구분되었다. MC1R 유전자형의 분포를 조사한 결과 제주흑우는 세 가지 대립인자가 모두 출현하였고, 황－적모색의 한우와 호피문의 칡소에서는 흑모색우성 대립인자 ED가 출현하지 않았다. 반면, 우성흑모색으로 알려진 두 소 품종 Holstein과 Angus는 ED 대립인자의 빈도가 96% 이상으로 조사되었다. 한우×Holstein F1과 한우×Angus F1은 모두 ED/e의 유전자형을 나타내었고, 표현형은 전신 흑색으로 확인되었다. 본 연구에서 고안한 이중 mismatch primer 쌍을 이용한 MC1R 유전자 증폭 절편에 대한 MspI-과 AluI-RFLP 조합은 소의 품종 특성 규명과 품종 식별에서 매우 중요한 유전자 표지인자 중 하나인 MC1R 유전자의 세 가지 대립인자를 식별하는 데 유용한 실험기법이 될 것으로 사료된다.

• Journal of Animal Science and Technology
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• 제45권1호
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• pp.13-22
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• 2003

성장호르몬 유전자는 하나의 작은 공통 선조 유전자로부터 아주 오랜 기간동안 유전자 중복에 의해 진화되어 온 그룹들 중의 하나이다. 이들에 속하는 유전자들은 동물 종간에 구조적인 상동성과 기능적 공통성 등 유사성이 비교적 높게 나타난다. 이런 연구결과들을 근거로 하여 소 성장호르몬 유전자에서 아미노산을 암호화하는 영역으로부터 새로운 아미노산의 변이(missense mutation)를 검출하였고, 이 변이의 대립유전자 빈도는 소(cattle)의 종(species) 및 품종의 지리적 분포에 따라 일정한 경향 치를 보여 주었다. 한편 변경되어진 아미노산은 Tryptophan으로 이는 생물체에 존재하는 많은 단백질들을 구성하는 아미노산중에서도 그 출현빈도가 가장 낮은 것이다. 또한 검출된 변이는 성장호르몬이 그의 수용체와 강하게 결합하는 부위로서, 성장호르몬의 구조적 변이를 초래하여 수용체와의 결합이 비정상적으로 이루어져, 이후 성장호르몬이 표적세포로의 신호전달과 같은 역할을 제대로 수행치 못하게 되고, 이로 인하여 가축의 표현되어지는 경제형질에 영향을 미칠 것으로 추정된다. 그러므로 이러한 대립유전자를 보유하는 개체는 집단에서 제거하는 방법에 의한 개량이 가능할 것으로 사료된다.

• Asian-Australasian Journal of Animal Sciences
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• 제31권3호
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• pp.327-334
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• 2018

Objective: The objective of the present study was to validate genes and genomic regions associated with carcass weight using a low-density single nucleotide polymorphism (SNP) Chip in Hanwoo cattle breed. Methods: Commercial Hanwoo steers (n = 220) were genotyped with 20K GeneSeek genomic profiler BeadChip. After applying the quality control of criteria of a call rate ${\geq}90%$ and minor allele frequency (MAF) ${\geq}0.01$, a total of 15,235 autosomal SNPs were left for genome-wide association (GWA) analysis. The GWA tests were performed using single-locus mixed linear model. Age at slaughter was fitted as fixed effect and sire included as a covariate. The level of genome-wide significance was set at $3.28{\times}10^{-6}$ (0.05/15,235), corresponding to Bonferroni correction for 15,235 multiple independent tests. Results: By employing EMMAX approach which is based on a mixed linear model and accounts for population stratification and relatedness, we identified 17 and 16 loci significantly (p<0.001) associated with carcass weight for the additive and dominant models, respectively. The second most significant (p = 0.000049) SNP (ARS-BFGL-NGS-28234) on bovine chromosome 4 (BTA4) at 21 Mb had an allele substitution effect of 43.45 kg. Some of the identified regions on BTA2, 6, 14, 22, and 24 were previously reported to be associated with quantitative trait loci for carcass weight in several beef cattle breeds. Conclusion: This is the first genome-wide association study using SNP chips on commercial Hanwoo steers, and some of the loci newly identified in this study may help to better DNA markers that determine increased beef production in commercial Hanwoo cattle. Further studies using a larger sample size will allow confirmation of the candidates identified in this study.

• Asian-Australasian Journal of Animal Sciences
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• 제25권11호
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• pp.1553-1558
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• 2012

This study was conducted to investigate the effects of stocking density or group size on feed intake, daily gain, and carcass characteristics of Hanwoo (Korean indigenous breed) steers reared from 7 months to 31 months of age. Thirty Hanwoo steers were divided into four groups with three replicates each (a total of 12 pens). In each group, one (G1), two (G2), three (G3), and four steers (G4) per pen were allocated as treatments. Pen size was $32.0m^2$, and therefore Hanwoo steers in G1, G2, G3, and G4 were reared under different space allowances, i.e. 32.0, 16.0, 10.6, and $8.0m^2$/steer, respectively. Steers were reared following a conventional beef cattle management method in Korea, and were offered a fixed amount of commercial concentrate with ad libitum forages. Results were subjected to analysis of variance with stocking density as the main effect, and significance was declared at p<0.05. Although total feed intake was not significantly altered, it numerically increased in animals of low stocking density (G1) compared to those subjected to high stocking density treatment (i.e. G4). Feed conversion ratio was higher (p<0.05) in G3 compared to G1 and G2. Animals in G1 (low stocking density) grew faster (p<0.05) than those of high stocking density (G3 and G4). Back fat thickness, meat yield index, and meat yield grade were similar among all levels of stocking density. However, longissimus muscle area was larger in G1 and G2 (p<0.01) compared to G3 and G4, and animals in G3 produced smaller carcasses (p<0.05). Carcass quality traits, including marbling score, meat color, fat color, texture, maturity and meat quality grade, as determined by a group of experts, were not significantly different among the treatments. In conclusion, lower stocking density resulted in increased feed efficiency, daily gain, and carcass weight in Hanwoo steers. However it remains unclear whether such differences are the results of stocking density or group size, or a combination of both. Nonetheless, these results confirm previous studies reporting a negative effect of increased stocking density on animal productivity. Further, animal welfare under an intensive farming system in relation to economical return is discussed.

• Asian-Australasian Journal of Animal Sciences
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• 제20권11호
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• pp.1636-1650
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• 2007

As an initial step toward a better understanding of the genome structure of Korean cattle (Hanwoo breed) and initiation of the framework for genomic research in this bovine, the bacterial artificial chromosome (BAC) end sequencing of 21,024 clones was recently completed. Among these clones, BAC End Sequences (BESs) of 20,158 clones with high quality sequences (Phred score ${\geq}20$, average BES equaled 620 bp and totaled 23,585,814 bp), after editing sequencing results by eliminating vector sequences, were used initially to compare sequence homology with the known bovine chromosomal DNA sequence by using BLASTN analysis. Blast analysis of the BESs against the NCBI Genome database for Bos taurus (Build 2.1) indicated that the BESs from 13,201 clones matched bovine contig sequences with significant blast hits (E<$e^{-40}$), including 7,075 single-end hits and 6,126 paired-end hits. Finally, a total of 5,105 clones of the Korean cattle BAC clones with paired-end hits, including 4,053 clones from the primary analysis and 1,052 clones from the secondary analysis, were mapped to the bovine chromosome with very high accuracy.

• 한국수정란이식학회지
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• 제31권3호
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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.