번식효율은 농가수입에 직접적으로 영향을 미치는 요인으로 암소뿐 만 아니라 씨수소의 번식효율은 중요한 경제형질로 여겨지고 있다. 본 연구에서 는 한우 씨수소에 대한 번식효율을 분석하기 위하여 2010~2017년에 전북지역 분만기록 62,284개와 이에 사용된 132두의 KPN에 따른 인공수정 수태율을 분석하였다. 종부차수(NAIPC)가 증가함에 따라 분만간격(CI), 공태기간(CCI)이 유의적으로 증가하였으며(P<0.05), 임신율은 낮아졌다. 첫 종부 임신율은 62.365%로 나타났으나, 3차 이후에는 48.147 이하로 급격히 낮아졌으며, 6차 이후에는 15.664% 이하로 낮아졌다. KPN과 인공수정사 모두 수태율에 크게 영향을 미치는 것으로 나타났다. KPN에 따른 수태율은 39.154~70.621%로 분석되었으며, 인공수정사에 따른 수태율 은 22.237~85.517%로 나타났다. 인공수정 실패 시 같은 KPN의 재사용율은 20% 내외로 특별한 경향은 보이지 않았다. 첫 종부 기록만을 이용하여 상대적 추정 수태율(ESCR)을 분석한 결과 KPN1041이 가장 높은 11.107%로 나타났으며, KPN1112는 가장 낮은 -20.591%로 나타나 31.698%의 차이를 보였다. 본 연구결과 인공수정사 뿐 만 아니라 전북지역에서 사용되고 있는 KPN에 따라 번식효율이 크게 영향 받을 수 있는 것으로 나타났다.

한국에 있어서 한우는 경제 동물일 뿐 만 아니라 중요한 유전자원 중 하나이다. 그러나 현재 한우의 번식 능력 개량을 위한 연구는 매우 미흡한 실정이다. 한우의 번식 능력에 대한 기초 자료를 확보하기 위해 전북지역(정읍시)에서 인공수정 된 암소 총 33,281두에 대한 105,017개의 번식기록(2010-2017)을 이용하여 임신기간(GP), 분만 후 첫 종부기간(CFSI), 분만 후 임신간격(CCI), 수태당 종부회수(NAIPC), 첫 종부 임신율 (FSCR)을 계산하여 분석에 활용하였다. 전체적으로 GP 는 287.602±4.797일, CFSI와 CCI는 각각 77.513±34.417 및 88.433±42.194일 이였다. 또한 FSCR는 62.365%였으며, NAIPC 는 1.411회로 나타났다. 2017년의 FSCR과 NAIPC는 각각 67.497% 및 1.344회로 2013년 62.366% 및 1.402에 비해 유의적으로 증가하였다(p<0.05). 가을과 겨울에는 번식기간이 더 길었으며, NAIPC는 봄과 여름에 비해 유의적으로 증가하는 것으로 나타났다(p<0.05). 3~7산차 암소의 경우 NAIPC가 1.323±0.669~1.339±0.689회로 다른 그룹에의 1.401±0.772~1.446±0.854회 보다 우수한 것으로 나타났다. 반면, 1산차 암소의 경우 FSCR와 NAIPC가 각각 60.217% 및 1.506±0.937회로 가장 저조한 것으로 나타났다. 본 연구 결과 한우의 번식효율은 산차에 따라, NAIPC는 계절에 따라 영향 받는 것으로 나타났으며, 전체적인 번식효율은 과거에 비해 지속적으로 향상되고 있는 것으로 나타났다.

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.

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.

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 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.

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.

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.

Calculating break-even price of calf production is closely associated with reproductive efficiency. To determine the price, we need data from reproduction records including number of claves weaned, number of cows exposed for breeding, and annual cash coast per cow, and average weaning or market weight of claves sold and retained. Unfortunately, the data were not available in Korea native cow (Hanwoo). To evaluate the performance and the price, we collected calving interval from about 60,000 cows for last 10 years and estimated reproductive performance. Calving interval was increased 4.3% and pregnancy rate was decreased about 1.4∼2.8% year-on-year. Increases in growth rates of number of cow and semen per calf supported the low reproductive performance. Finally, break-even price was calculated using estimated percent calf crop and demonstrated that growth rate of break-even price is larger than that of annual cash per cow, suggesting cow-calf profitability and financial efficiency in Korea native cow (Hanwoo) is getting worse.

These studies were conducted to establish the practical Hanwoo (Korean native cattle) improvement system through the combining of embryo transfer technology and confirming individual Hanwoo oocyte culture system and to investigate that correlation of Hanwoo carcass classification (intramuscular marbling) and oocyte donor for blastocyst production in vitro. In case of Hanwoo, the carcass meat quality grades were divided to grade 1⁺⁺, 1⁺, 1, 2, and 3 depends on fat distribution of longest muscle cross-sectional surface. As results, the numbers of follicular oocytes collected from individual fundamentally-registered Hanwoo yielded 1⁺⁺, 1⁺, 1, 2 and 3 meat quality were 9.5, 9.4, 8.5, 8.8 and 8.8 per ovary, respectively. The numbers of retrieval oocyte from follicles were significantly higher in the cattle yield 1⁺⁺, 1⁺ meat quality than in the cattle yield 1, 2 and 3 meat quality (p<0.05). The rates of blastocyst formation were 18.2, 21.3, 29.4, 30.9, and 31.5% in the cattle yield 1⁺⁺, 1⁺, 1, 2 and 3 meat quality of after in vitro maturation, respectively. It was significantly lower in the cattle yield 1⁺⁺ and 1⁺ meat quality than in the cattle yield 1, 2 and 3 meat quality (p<0.05). In order to evaluate embryos quality, TUNNEL assay was conducted for each meat quality grade using blastocyst stage embryo on day 8. The results showed that apoptosis cell number was higher tendency in the cattle yield 1⁺⁺and 1⁺ meat quality (81 and 79, respectively) than in the cattle yield 1, 2 and 3 meat quality (51, 48 and 50, respectively) but there was no statistical significance in each group. After embryo transfer, the conception rate of recipient was 53.5 (23 out of 43), 52.1 (38 out of 73) and 58.0% (58 out of 100) in the meat quality of 1, 1+ and 1++, respectively. These results showed that the conception rate was significantly higher in the cattle yield 1 meat quality than in the cattle yield 1⁺⁺, 1⁺ , 2, and 3 meat quality (p<0.05). In summary, these results indicate that the application of confirming Hanwoo individual oocyte culture system and embryo transfer technology can make good use of the genetic resources conservation and improvement of Hanwoo. Relevance of the meat quality grade and reproductive ability of carcasses of Hanwoo will be considered to be one of the effective means for the associated research with obesity and reproduction.

The purpose of this study is to produce wanted sex progeny of genetically confined White Hanwoo (albinism) with preselected sex sperm. One bull of White Hanwoo was chosen for semen donor and X sperm was sorted by MoFlo XDP cell sorter. To compare the pregnancy and birth rates, KPN straw was used as control, total number of unsorted sperm was 20×106/straw. Sexed X frozen semen with 2×106 cells or 4×106 cells per straw were in seminated twice on Hanwoo heifers. The abnormality of the sexed X semen was 24.9 ± 7.31% and distal reflex abnormality of mid piece was significantly (p<0.05) higher (11.7%) compared with that of KPN 768 (5.6%). There were no differences on the pregnancy and birth rates between 2×106 cells or 4×106 cells of X-sperm but KPN semen showed significant differences (p<0.05). The pregnancy rates of KPN 768, 2×106 cells and 4×106 cells X-sperm of White Hanwoo cattle were 85.0%, 26.3% and 50%. The birth rates were 80.0%, 15.8% and 21.4%, respectively. The female offspring rates of KPN 768, 2×106 cells and 4×106 cells X-sperm of White Hanwoo cattle were 43.8%, 100% and 100% (p<0.05). These results indicated that sex sorted White Hanwoo could be used for the production of wanted progeny with 2×106 cells/straw for AI. To increase the efficiency of calf production, the sperm number of sex sorted semen will be optimized for sex selection of White Hanwoo progeny.

Sexed semen is commonly used for the production of calves of the desired gender. Gender selection is important in animal production industries. For example, female cattle are required for the dairy industry while males are preferred in the beef cattle industry. The present study was to assess the in vivo embryo production efficiency using the semen separated according to sex during superovulation in Hanwoo. Seventy Hanwoo donor cows were flushed on day 7 of estrus cycle with same FSH and artificial insemination by the same technicians. Embryos were recovered on 7 days after the third insemination by flushing the uterus with embryo collection medium. KPN semen straws used artificial insemination contained 20 million sperm (total number 60 million per donor). Sex-sorted semen straws contained 4 million sperm (total number 12 million per donor). The results obtained were as follows: No differences were observed in the efficiency of superovulation rates on KPN semen 87%, and sexed semen 100%, respectively. The mean numbers of total embryos are each 12.58±8.31 and 13.25±7.86. The mean numbers of transferable embryos, sexed semen were significantly lower than KPN semen (3.75±1.98 vs. 8.23±6.07, P＜0.05). The rates of unfertilized embryos from superovulation using sexed semen were significantly higher than KPN semen (50% vs. 15%, P＜0.05). The rate of degenerated 2-cell embryos from sexed and KPN semen was 60.87% and 11.11%, respectively (p＜0.05). In conclusion, these results indicate that superovulation using sexed semen was useful, but efficient embryo production was important to reducing the damage caused by the Flowcytometer-based sperm sorting procedure.

The objective of this study was to evaluate several types of uterine bacteria in Hanwoo. uterine bacteria from randomly selected 5 uterus was collected by flushing methods into a sterilized 1.5 ml centrifuge tube and was inoculated onto MacConkey agar and blood agar, respectively. After being incubated for 5% CO2, aerobic or anaerobic condition at 37℃ during 48h, bacterial colonies were selected and re-inoculated onto blood agar plates. Re-cultured colonies were identified by Gram staining and finally identified using Vitek system. The identified bacteria were Staphylococcus lentus, Staphylococcus sciuri, Staphylococcus vitulinus, Staphylococcus warneri of Gram (+) and Rhizobium radiobacter, Sphingomonas paucimobilis of Gram () bacteria. Although, pathogenicity of identified bacteria was unclear, the bacteria can have an effect on the uterine microenvironment. Therefore, repetitive research will be required to determine the effects of bacteria in cattle exposed to a various environment.

Solution of glycerol, ethylene glycol, sucrose, dextrose (GESD) and cryotop methods were carried out to investigate the survivability on vitrification of embryos. Embryos cultured in vitro were vitrified by GESD of 10 or 8 step and cryotop methods of 6 step, from cryopreservation step to frozen-thawed and culture step. Survival rate and ICM, TE cells of embryos were investigated after frozen-thawed 24 h. As a results, cryotop method was significantly (p<0.05) higher ( vs. , ) than GESD 10 or 8 step methods on survivability. Also, In ICM cell number, cryotop method was significantly (p<0.05) higher to cells than GESD 8 step method. TE cell number was significantly (p<0.05) highest to cells in cryotop method. On the other hand, survival rate, TE and total cell number were all the significantly (p<0.05) high, except ICM in GESD 10 step method between GESD 10 step method and GESD 8 step method. In conclusion cryotop method was to be most effective, but it is considered necessary to study vitrification method for step-by-step freezing and thawing process.

This study was carried out to effects of ethylene glycol concentration, sucrose and culture day of in vitro production embryo on slow-down freezing in Hanwoo. 6, 7, 8 and 9 day embryos produced in vitro were frozen using 1.8M EG+0.1M sucrose, 1.8M EG+0.5% BSA and 1.5M EG+0.1M sucrose media. Survivability was confirmed after frozen-thawed 24 and 48h and ICM, TE cell number were counted by Hoechst 33342 and PI staining after frozen-thawed 24h. As a result, 1.8M EG+0.1M sucrose group was most significantly (p<0.05) higher compared with the other treatment groups on survivability, TE and total cell number after frozen-thawed 24h (, and ). ICM number did not found significant (p<0.05) differences between the three treatment groups. in 6, 7, 8 and 9 day of embryos using three types of freezing media, frozen-thawed, 1.8M EG+0.1M sucrose groups with embryos cultured 8 day was significantly (p<0.05) highest survivability to after frozen-thawed 24h. 1.5M EG+0.1 sucrose group with embryos cultured 9 day was significantly higher survivability than group of embryos cultured 8 day after frozen-thawed 24 and 48h. In conclusion, 1.8M EG+0.1M sucrose media is considered to be effective to cryopreservation of embryos cultured 8 and 9 day.