This study was conducted to investigate the optimal artificial insemination (AI) time with diagnostic kit at ovulation time. We already applied the patent about the protein in the cow heat mucose in external reproductive tract. And we would examine the accuracy for detection of cow heat by the kit produced with the protein. Evaluation of optimal heat detection was tried two time at 12 hrs and 24 hrs after the heat. And then, AI service also performed two times with no relation to the results of heat diagnosis by heat detection kit and pregnancy rates were checked with rectal palpation on 60th day after AI. Heat diagnostic results by kit in natural heat after 12 hrs in Hanwoo cows were showed 31.3~75.0% on positive in first heat detection and 33.3~100.0% on positve in second heat detection. In the 1st positive results were significant different (p<0.05), but 2nd positive were not. The results of heat detection showed different result on regional influence and individual cow effects. The pregnancy rates of first trial of heat detection were showed 34.4~78.7% on positive and 21.3~68.8% on negative after the diagnosis by heat detection kit. And the pregnancy rates of next trial of heat detection were showed 33.3~85.7% on positive and 14.3~66.6% on negative after the heat diagnosis. Both positive results of first trial and next trial also were showed significant different (p<0.05), but negative results were not. In positive result, first trial of total pregnancy rates was higher than the next trial of pregnancy, but there showed opposite results on negative results. In conclusion, the optimal heat detection kit is suitable to ordinary Hanwoo cows and it suggested that we have to improve the kit’s accuracy by detecting the materials like proteins related optimal AI time.

The coat color of mammals is determined by the melanogenesis pathway, which is responsible for maintaining the balance between black-brown eumelanin and yellow-reddish pheomelanin. The melanogenesis-associated genes controlling pigmentation act as a complex and interact with each other to cause phenotypic and genotypic variations in cattle. That the MC1R genotype of Korean native cattle with dark muzzle was e/e or E+/e, while the genotype of Korean native cattle with light muzzle was E+/E+, which is a variant of the MC1R genotype in the Korean native cattle. Especially, the MC1R expression type is shows how much pigmentation, important factor in deciding its status in the coat and nose colours. However, information regarding the coat or nose colours-associated gene regulation of korean cattle is not yet unknown. Therefore, in this study was to investigate the expression patterns of melanogenesis-associated genes in black dot nose(korea brindle cattle) and normal nose(korea native cattle). Using microarray clustering and real-time polymerase chain reaction techniques, we analysed that the expression of genes involved in the mitogen-activated protein kinase (MAPK) and Wnt signaling pathways is distinctively regulated in the dark and light muzzle tissues. Differential expression of tyrosinase was also noticed, although the difference was not as distinct as those of MAPK and Wnt. We hypothesize that emphasis on the MAPK pathway in the Korea brindle cattle induces eumelanin synthesis through the activation of cAMP response elementbinding protein and tyrosinase, while activation of Wnt signaling counteracts this process and raises the amount of pheomelanin in the native cattle. Regarding the increasing interest in the genetic diversity of cattle stocks, genes we identified for differential expression in the brindle cattle vs. native cattle may serve as novel markers for genetic diversity among cows based on the coat and muzzle color phenotype.

Bovine leukemia virus (BLV) is the causative agent of enzootic bovine leukosis. This study was conducted to clarify the seroprevalence of BLV in the Republic of Korea. Blood samples were obtained from Korean native cattle farms in all provinces of South Korea except Jeju. A commercial indirect enzyme-linked immunosorbent assay with 4,498 samples to detect antibodies against BLV was conducted. The results revealed that the prevalence of BLV was dependent upon age, with increasing prevalence among cattle occurring until they were 5 years old. The highest seroprevalence in cattle was observed in Chungnam (29.6%) and the lowest was observed in Jeonnam (2.6%). The mean overall prevalence for BLV antibodies in the survey was 10.2%, indicating that BLV is widespread nationwide.

Cryopreservation of germ cells from genetically proven animals could be a source of restoration tools from the risk of extinction or disappearance of wanted characteristics. Using frozen semen, the genetic gains of Korean native cattle have been increased greatly for 70 years. The preservation of genetic resources as a form of frozen semen straw has limited availability due to the numbers. To circumvent this weakness of frozen semen, we tested two re-freezing methods with different initial thawing temperatures using frozen Korean proven semen and rare breed semen from albino, black and chikso breeders. It has been known that human sperm could resist to cryo-damages by repeated freeze-thaw cycles, but not for Korean proven bulls number (KPN) or for rare breeds. Total 7 frozen semem from brindled(2), black(1), Korean Albino(2) and KPN(1) bulls were used for our research. After thawing straws under 5°C/2min or 37°C/40sec with low temperature water bath and thermo jug, spermatozoa were re-diluted with triladyl diluents after first thawing and re-frozen. Sperm motilities were compared between animals and treated groups after re-thawing. Mean values of motility and viability of refrozen/thawed sperm for expansion of the number of straws were significantly higher in 5°C than in 37°C (P< < 0.05). However, the activity of viable sperm thawed at 5°C was significantly decreased after first and second thawing. It is estimated that re-freezing of frozen semen from rare Korean native cattle is possible with resistant properties of survived spermatozoa.

This study aimed to indentify single nucleotide polymorphisms (SNPs) in exon region of the glycerol-3-phosphate dehydrogenase 1 (GPD1) gene and to evaluate their associations with meat yield and quality traits in Hanwoo (Korean cattle). Two SNP markers, g.2766C>T and g.5105A>G were identified in the exons 5 and 8, respectively. Genotyping of the two SNPs was carried out using PCR-RFLP analysis in 309 Hanwoo steers to evaluate their associations with meat yield and quality traits. As a result, g.2766C>T in exon 5 was significantly associated with carcass weight (CW) and marbling score (MS). Animals with the CC genotype of g.2766C>T had heavier CW than those with the CA or AA genotype. Animals with the CC genotype of g.2766C>T also had higher MS than those with the CA or AA genotype. Additive effect was also observed with CW and MS traits. We constructed haplotypes by linkage disequilibrium analysis and analyzed association between haplotypes and meat yield and quality traits. Haplotype of GPD1 gene was associated with CW. As a result, animals with CA haplotype had heavier CW than TG haplotype. These findings suggest that the SNPs of bovine GPD1 gene may be a useful molecular marker for selection of meat yield and quality traits in Hanwoo.

This study was conducted to report the census survey results of south Korean Chikso (Korean Brindle Cattle) distribution and to diagnose the current coat color expression patterns. Two years Chikso census showed that there were 2,413 Chikso in 2013 and 2,754 in 2014 in south Korea. Number of animals between 0 to 35 months of age was 1,632 heads in 2014 which comprised 59% of total Chikso population size. The percentages of animals between 36 ~ 71 months of age and over 6 years of age were 31% and 10% of total. Out of 2,416 animals with class numbers assessed by their coat colors, 1,249 heads (52%) were in group I (with black stripes, class no. 1 ~ 3) and the others (class no. 4 ~ 7) were in group II (1,167 heads, 48%). Among the 1,551 animals that were photographed twice in 2013 and in 2014, 226 animals were assessed different coat color class numbers, and round 90% of which were within the ages less than 48 months. The number of animals switched in coat color pattern groups over a year was 56, which was 3.6% of total number of animals on survey. And around 88% of the animals switched in group category was of the animals younger than 24 months of age. Therefore, we conclude that the coat color pattern becomes rather stable at around 24 months of age in Chikso populaion in south Korea.

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 R² = 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±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.

Wholesale beef price is the critical factor for determining Korean native cattle, Hanwoo, farm’s income in short-term. Wholesale beef price has seasonality due to high demand in Korean traditional holidays such as Korean thanksgiving day and lunar new year’s day. Therefore, it is important to make reproduction and marketing plans for Korean Hanwoo farmers, in order to increase their farm income. However, there is no study available on changes in the expected farm income depending on reproduction and marketing schedules. This study analyzed the expected farm income per head depending on the monthly-based marketing schedules. The analysis was conducted based on the seasonality of wholesale beef price, reproduction efficiency, operating costs, relationship between carcass grade and slaughter age. The result shows that slaughter Hanwoo at the age of 29 months-old in August and January generating the highest expected farm income per head.

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), R² = 0.98881. In summary, we can determine the best timing of AI using body measurement and its application including BMI.

The objective of this study was to investigate the effect of amino acid and vitamin C supplementation on the quality attributes of top round (TR) muscle from Korean cattle (Hanwoo). Sixteen-month-old steers were divided into three different feeding groups and raised until they were 28 months old. A control group (9 heads) was fed a basal diet and rice straw, whereas two experimental groups (8 heads/group) were fed a basal diet and rice straw supplemented with rumen-protected amino acids (≥16.0% L-lysine monohydrochloride, ≥8.0% DL-methionine) and vitamin C at a dose of 100 g/head/day (AA+VC group) or only vitamin C at 100 g/head/day (VC group). After slaughter, TR muscle (M. semimembranosus) was collected from carcasses and used to measure the quality attributes. Crude fat content was significantly higher (p<0.05) in the AA+VC group than in the VC group. No significant difference was observed for water-holding capacity and shear force value between the control, AA+VC, and VC groups. Contents of the free amino acids (FAAs) glycine, aspartate, and glutamate were significantly higher (p<0.05) in the VC group than in the control group. Sensory evaluation of tenderness and flavor preference revealed significantly higher scores (p<0.05) in the AA+VC group than in the control group. These findings suggest that vitamin C supplementation increases the contents of some FAAs, and the combined supplementation of amino acids and vitamin C improves the marbling and sensory attributes of TR muscle in Hanwoo.

The KLF(Kruppel-like factors) are transcriptional regulators that including the C2H2 zinc-finger motif and regulation of cell growth, cell differentiation, and development. In this study, mRNA and total DNA was extracted from the meat around the backbone of 130 cattle that has economic traits score. The KLF11 gene was act on the center of the main pathway in associated with the development and growth of cells and the fat metabolism. Genetic polymorphism was detected by DNA sequencing. A total of four SNPs(G9047A, C9104G, G9131A, C9170T) were identified in exon 4 regions, statistical association analysis revealed that the G9131A polymorphism were significantly associated with marbling score. The real time quantitative PCR to investigated gene and miRNA expression patterns and identify the relation of economic trait in Korean Native Beef Cattle. Gene expression level linked to KLF11 genes was investigated by determining its association and variation with the economic traits in Korean Native Beef Cattle. The increment of KLF11 gene expresstion level is resulted in increasing marbling score(MS). We found that expression profile of KLF gene and mir-494 was contrast tendency because the lower expression ratio of gene was the higher marbling score rating was when we analyzed expression profile ofKLF gene and mir-494. Therefore, this result has useful in improvement of livestock in Korean cattle.

In experiment dealt with 240 Hanwoo (172 steers and 68 heifers) among the 456 cattle during growing and fattening period were used from 2004 to 2015. Growth period was divided into 6, 12, 18, and 24 months for steers and 6, 12, 18, and 43 months for heifers. The results showed that lying down, feeding, and drinking behavior increased according to the growth. In contrary, the time of locomotion behavior including standing and walking behavior were reduced. Aggressive behavior was observed to be mostly generated in the first 6-months. Thus the results showed that different growth period of Hanwoo steers can be used as management systems for breeding and disease management. It conclude that providing a comfortable living space is a useful management systems suppress stress to the minimum extent without giving unnecessary stress to the animals.

농장동물복지형 한우 사양관리를 통한 고품질의 쇠고기 생산을 목표로 세계적인 트랜드에 부합하는 축산선진국으로 나아가기 위하여 본 시험으로 우방내 사육공간의 넓이차이에 따른 한우의 사양성적, 행 동특성 및 혈액성상에 미치는 영향을 비교·분석해 보았다. 16개월령의 한우 54두(암소 미경산공태우 및 거세우 각각 27두)를 공시하여 성별에 따라 사육공간의 넓이차이를 주기 위해 4두(8m2), 3두 (10.67m2) 및 2두(16m2)로 처리하여 9개월간 각각 3반복으로 완전 임의배치 후 실시하였으며, 한우 사 양관리 프로그램에 따라 사료급여를 하였다. 데이터 수집방법으로 증체량, 사료요구율 및 혈액분석은 2 개월 간격으로 반복하여 측정하였으며, 행동패턴 수집은 복수개체 추적방법 및 선택적 행동관찰법으로 기상청에서 제공한 맑은 날을 선정하여 15일간 녹화 후 분석에 이용하였다. 본 시험의 결과로, 사양성 적(체중, 일당증체량 및 사료요구율)의 경우 미경산공태우와 거세우 각각 20개월령과 18개월령 이후부 터 2두와 3두 처리구에서 모두 유의적(p<0.05)으로 향상되었다. 행동특성으로는 미경산공태우의 2두 처 리구에서 행동시간으로 기립행동은 유의적(p<0.05)으로 낮고, 횡와 및 걷기행동은 유의적(p<0.05)으로 높았다. 행동빈도에서는 음수, 자기몸핥기, 긁기, 몸비비기, 투쟁행동에서 유의적(p<0.05)으로 적게 나 타났다. 거세우의 2두 및 3두 처리구에서는 미경산공태우와 유사한 경향을 나타냈으나 유의적(p<0.05) 으로 섭식시간은 증가하고, 다른소핥기 및 몸기대기의 빈도는 유의적(p<0.05)으로 적게 나타났다. 혈액 성상으로 미경산공태우와 거세우의 4두 처리구에서 적혈구가 유의적(p<0.05)으로 낮았고, 콜티졸은 유 의적(p<0.05)으로 높게 나타났다. 또한, 미경산공태우의 헤모글로빈과 거세우의 백혈구 수치에서는 모 두 2두 처리구에서 유의적(p<0.05)으로 각각 높고 낮은 것으로 분석되었다. 이상의 결과를 종합하면 사 양성적, 행동특성 및 혈액성상 등의 전체적인 내용을 토대로 우사의 여유 및 표준우사의 우방크기를 고 려할 때 한우의 사육공간에서 관행사육인 4두 처리구(두당 8m2) 보다 미경산공태우는 2두 처리구(두당 16m2), 거세우는 3두 처리구(두당 10.67m2)로 사육하는 것이 적절하다고 판단되며, 본 시험결과는 추후 복지형 한우의 사양관리를 위한 기초자료로 활용할 수 있을 것으로 판단된다.

The objective of this study was to investigate the result of in vivo embryo collection and pregnancy rate after embryo transfer using sex-sorted sperm of Korean brindle cattle. Donor Korean brindle cattle superovulation treated by decreasing dose of FSH injection. Embryos were recovered on 7 days after the third artificial insemination. Control group semen straw used artificial insemination contained 20 million sperm. Sex-sorted semen straws contained 4 million sperm or 10 million sperm. As for the result of the recovery of the in vivo embryos derived from sex-sorted sperm, the number of transferable embryos was significantly highly recovered to be 6.20±2.28/donor from the control group and was significantly lowly recovered to be 1.57±1.72/donor from the group treated at a sperm concentration of 10×106 (p<0.05). The number of unfertilized embryo was 0.8±1.30/donor in control group which was significantly lower than the group treated at a sperm concentration of 4×106 (p<0.05). However, there was no significant difference in the number of undeveloped ova between control and treatment groups. Pregnancy rate after embryo transfer was shown to be 35.00% in control group and 12.50% in treatment group. The karyotype analysis of the calf derived from sex-sorted sperm resulted in a similar chromosomal distribution pattern (2n=60, XX) compared to those of common Korean native cattle.

In this study, the texture, nucleotide-related compounds, and sensory characteristics of dry-aged beef, made from third quality grade Hanwoo beef (Korean native cattle), were investigated according to aging periods. Loin cuts obtained from three different Hanwoos were dry-aged under the specific conditions (controlled temperatures, humidity, and air flow) during 0-7 weeks. With increasing aging periods, textures were significantly decreased after 5 weeks (hardness: from 13,264±2,033 to 7,112±1,743 g; chewiness: from 4,107±1,467 to 2,334±780) and four sensory characteristics were significantly increased after 3 weeks (texture: from 2.2±1.0 to 6.2±1.1; flavor: from 3.9±0.7 to 6.2±1.5; whole preference: from 2.5±0.8 to 6.3±1.3; purchase intention: from 3.7±1.4 to 6.0±1.5) except for color (p<0.05). On the other hand, the concentrations of IMP which is related to the umami flavor of beef were significantly decreased with increasing aging periods (from 40.44±5.97 at 0-week to 7.44±2.43 μg/ mg at 7-week) (p<0.05). These results obtained in this study could provide an useful data base for the quality control of dry-aging.

이 연구의 목적은 성염색체 특이적 초위성체마커의 대립 유 전자 다양성과 빈도를 조사하여 한국 재래소 3품종의 (칡소, 한우 그리고 제주흑우) 유전적 근연관계 및 특징을 조사하여 우리 고유 유전자원으로서의 가치를 구명하고자 하였다. 한국 재래소 3품종은 30개의 초위성체 마커에서 선별된 4개의 초 위성체 마커(INRA30, TGLA325, UMN0905 및 UMN0929) 를 이용하여 식별하였다. 대립 유전자의 다양성, 대립 유전자 빈도, 이형접합도 그리고 다형 정보량(PIC)을 산출 하였다. 칡 소, 제주 흑우와 한우에 대한 관찰 이형접합도의 평균은 각각 0.541, 0.406 및 0.61이었고 PIC의 평균은 각각 0.542, 0.377 그리고 0.6이었다. 제주흑우의 경우 칡소나 한우에 비해 낮은 이형접합도와 PIC를 보여준다. 이들 4개의 초위성체 마커를 이용하여 칡소, 제주흑우 그리고 한우의 품종을 구별에 이용 할 수 있다. 이러한 결과들로 볼 때 한국 재래소 3품종은 가 축유전자원으로서 중요한 가치를 지니고 있으며 이들 품종의 보존, 관리 및 활용에 중요한 기초자료로 이용될 것으로 사료 된다.

The aim of this study was to investigate the effects of different rearing spaces on growth performances, behavioral traits, and blood parameters in Hanwoo (Korean Native Cattle) heifers and steers. The average daily gain and feed conversion ratio were measured to assess the growth performance. A total of 54 Hanwoo heifers and steers at 18 months old, were housed separately in groups of 2, 3 or 4 heads in a pen (32 m2) for nine months. In the case of the heifers, the growth performances were significantly (p<0.05) improved by increasing the 2 head group size with the exception of the 18 month old heifers. However, among the steers the growth performances were significantly enhanced (p<0.05) after 18 months of age, by increasing the 3 heads group size. In addition, the heifers in groups of 2 heads spent less time standing and more time lying down or walking, and also had a significantly (p<0.05) lower frequency of self-grooming, scratching, and fighting. These findings are similar to the results obtained for steers housed in 2 or 3 heads per group. The steers housed in 2, 3 heads groups spent more time feeding and consequently had a significantly (p<0.05) lower frequency of pair-wise grooming and Leaning. The heifers and steers housed in groups of 4 heads showed lowest red blood cell counts, but highest cortisol content with statistical significance at p<0.05. The heifers in groups of 2 heads had the highest hemoglobin concentrations (p<0.05). On the other hand, white blood cell count was found to be the lowest in groups of 2 steers with statistical significance at p<0.05. We conclude that a large rearing space improved growth performances, behavioral characteristics, and blood parameters in Hanwoo heifers and steers. In the future, this data could be used to improve the welfare of rearing Hanwoo cattle.

The objective of this study was to identify the phenotypic relationships among calving difficulty, calf birth weight and gestation length of Holstein dairy cattle under the environment of Korea. A total of 1,834 calving records collected by Dairy Science Division of National Institute of Animal Science, RDA from 2000 to 2014 was analyzed. General linear multivariate models for calving difficulty scores (CD: 1=no assistance, 2=minor assistance, 3=two to three persons assisted, 4=more than three persons assisted, 5=cesarean section), calf body weight at birth (BW), and gestation length (GL) included fixed effects of year and season (spring, summer, autumn, winter) of births (YS), sex of calves, and parity. For GL and BW, all three fixed effects (YS, sex of calves, parity) were significant (p<0.05). For CD, the effects of YS and sex of calves were significant (p<0.05). Bull calves were born with heavier BW by 3.18 kg, with greater CD by 0.18 point and with longer GL by 0.6 days than heifer calves. The least squares mean of BW was the heaviest at the third parity (44.1 kg) compared to those at the first, the second and the fourth parities or later (41.3-41.9 kg). The least squares mean CD at the first parity was 1.74 point, which was higher than CD at the second and later parities (about 1.68 points). Phenotypic correlation (partial residual correlation) between GL and BW was 0.36. But those between GL and CD and between BW and CD were -0.03 and 0.04, almost zeros. To conclude, we observed higher incidence of calving difficulty in the first calving than in the later ones. Further investigation on the relationships between calf’s birth weight and calving difficulty is needed

케토시스 지표형질에 영향하는 환경요인을 살펴보기 위하여비유단계, 계절 및 착유시간에 대한 생산형질의 변화를 살펴보았다. 유량은 비유일수가 증가할수록 높아지는 추세를 보였고, 유지방 함량, 유단백 함량, 무지고형분 함량은 DIM1(비유초기)에서 가장 높게 나타났다. 계절에 따른 생산형질의 변화를 살펴보면 유량은 봄·겨울에 높게 나타났고, 유지방 함량과유당 함량, Acetone 및 BHBA 모두 가을에 높게 나타났다.또한 유량은 오전 착유시간이 높았고, 유지방 함량 및 유단백함량은 오후 시간대가 높게 나타났다. 환경요인에 따른 생산형질 및 케토시스 지표형질의 함량은 모두 유의적 차이를 보였으며, 분석모형을 설정함에 있어 위의 환경요인은 고려되어야 할 사항이다. 생산형질과 케토시스 지표형질의 상관관계 분석 결과 유량의 경우 Acetone 및 BHBA의 수치가 증가할수록 감소하는추세를 보였고, 유지방 함량은 반대로 Acetone 및 BHBA의수치가 증가할수록 증가하는 경향을 보였다. 비유단계와BHBA의 농도는 음의 상관관계를 보인다는 기존의 결과와 반대로 분석결과 양의 상관관계를 보였다. 유전력은 착유일5 ~ 20일에서 0.03 착유일 21 ~ 40일은 0.05 착유일 41 ~ 60일은 0.04 착유일 61 ~ 80일은 0.08 착유일 81 ~ 100일은 0.04의 유전력을 보였다. 이는 비유 5일째에 준임상형 케토시스의발병률이 가장 높게 나타난다는 기존의 연구결과에 비추어 볼때 유전력이 낮게 추정된 것으로 사료되며, 이는 1산차의 분석 자료수가 충분치 않은 결과로 추정된다. 케토시스 저항성개체 선발을 위한 유전평가모형에 적용가능한 선발지수를 개발하기 위해서는 여러해의 축적된 자료를 이용한 분석이 필요한 것으로 판단된다.