This laboratory study was conducted to evaluate the effects of oyster shell by-product (OSB) on the characteristics of Hanwoo cow manure and emitted gases. For the treated groups, 0.5% and 1% OSB were applied to 200 g of Hanwoo cow manure in a container box with three replications each per group with a group without OSB (0%) as a control group. All samples were stored at room temperature to analyze pH, volatile basic nitrogen (VBN), volatile fatty acid (VFA), and gas emissions (NH3 and H2S) from Hanwoo manure on 0, 2, 4, and 8 days. No group exhibited a significant (p>0.05) effect on VBN, acetate, and propionate values during the 8 days. On day 0, pH increased by 1% OSB application, but no effects on the other days. Iso-butyrate concentration increased (p<0.05) on day 0 by OSB application, but deceased (p<0.05) on day 8. The NH3 gas emission on day 2 decreased (p<0.05) in all treatments applied OSB. However, either NH3 or H2S gases in all treatments were below 0.25 ppm on days 4 and 8, which were no differences (p>0.05) among treatments. Thus, this lab study indicated that the inclusion of OSB application in Hanwoo cow manure had a beneficial effect on NH3 gas emission, but no longer than for 2 days.

현재 한우에서는 영양대사물질 수준에 대한 연구가 미흡한 수준이다. 따라서 본 연구는 한우 번식우에 있어서 임신과 비임신 상태에 있어서 혈액내 주요 영양대사물질을 분석하였다. 한우 번식우 54두를 방목을 하였을 경우에는 혈액내 주요대사물질 6개 항목(AST, ALT, Cholesterol, Glucose, BUN, NEFA)을 분석하였다. 사육방법과 관련된 NEFA수준 조사에서 방목우 임신우 평균은 221±105 uEq/L이고, 사사 사육 임신우 평균 240±121 uEq/L로 나타났으나 유의적인 차이는 없었다. 콜레스테롤 수준은 사사 사육시 임신우 113.33±17.03 mg/dL이었고, 비임신우는 137.25±21.77 mg/dL로 비임신우에서 유의적으로(p<0.05) 높은 결과를 보였다. 사사 사육시 NEFA 수준(임신우 204±119 uEq/L과 비임신우 286±215 uEq/L)도 콜레스테롤 수준과 동일한 경향을 보였다. 분만 전ㆍ후 AST 수치는 각각 105.53±24 IU/L와 81.59±12.55 IU/L으로 분석되어 분만 후에서 유의적으로(p<0.05) 감소한 결과를 보였다. NEFA 수준에서는 분만 전 122±52 uEq/L, 분만 후 497±239 uEq/L 로서 분만 후에서 유의적으로(p<0.05) 높은 결과를 보였다. 이러한 NEFA 수준의 증가는 분만 후 번식우가 필요로 하는 영양대사물질이 증가하였기 때문인 것으로 사료된다. 이러한 결과를 종합하면 한우 번식우의 적정한 영양수준 관리는 생산성을 향상 시킬 수 있을 것으로 사료되며 한우 번식우에 대한 영양수준 연구는 추가적으로 연구가 이루어져야 할 것으로 사료된다.

본 연구는 미네랄 첨가제가 한우사 바닥에 미치는 영향을 조사하였다. 실험은 경남 진주시 소재 한우 번식우 농장에서 실시하였다. 우방당 미네랄 첨가제를 5 ㎏ 첨가하였으며, 시험구로는 무첨가구(CON); bentonite 시험구(BN); illite 시험구(IL); 및 fly-ash 시험구(FA)로 두었다. 각각의 시험구로 4개의 우방을 이용하였으며, 우방당 5마리 한우 암소를 공시하였다. 미네랄 첨가제를 처리한 후 각 우방당 5곳에서 0, 7, 14, 21 및 28일에 우분을 채취하였다. 샘플은 건물, 발효특성, 미생물 성상 및 가스 발생량 분석에 이용되었다. 전 기간 동안 건물과 acetate 함량은 미네랄 첨가제에 의한 영향은 나타나지 않았다. 무첨가구에서 7, 14 및 28일에 유기물 함량은 가장 높았고(p<0.05), 조회분 함량은 가장 낮았다 (p<0.05). IL 시험구에서는 14, 21 및 28일에 총 질소 함량이 가장 높았고(p<0.05), IL, BN 및 FA 시험구에서는 각각 14, 21 및 28일에 무첨가구보다 대장균이 낮았다(p<0.05). FA 시험구에서는 28일에 살모넬라 수가 가장 높았다(p<0.05). IL 시험구에서는 28일에 암모니아 발생량이 가장 높았고 (p<0.05), 황화수소는 전기간 동안 검출되지 않았다. 28일간 결과값을 평균하였을 때, 무첨가구에서 유기물 함량이 가장 높았고(p<0.05), 조회분 함량이 가장 낮았다(p<0.05). IL 시험구에서 총 질소 함량이 가장 높았고(p<0.05), BN 시험구는 ㏗가 가장 높았다(p<0.05). 대장균 수는 IL 시험구에서 가장 낮았고(p<0.05), 살모넬라 수는 무첨가구 보다 IL과 FA 시험구에서 더 낮았다(p<0.05). 따라서, 본 연구에서 광물질 첨가제는 분 중 가스 발생량에는 영향을 미치지 않았으나, 병원성 미생물인 대장균은 illite와 fly-ash 처리 시에 억제되는 효과가 있었다.

본 연구에서는 한우 암소와 씨수소의 육종가를 기반으로 연도별 유전적 개량량을 추정하여 현재 한우 축군의 개량 정도를 파악하여 향후 한우 개량 방향을 위한 기초자료로 활용하고자 본 연구를 시행하였다. 본 연구를 위하여 한우농가 4,040호에서 축산물품질평가원에 도축된 970,567두의 도축자료를 이용하여 10번 반복되어 추출된 표본 자료와 한우농가에서 2009년부터 2019년까지 사육되고 도축된 개체 중에서 한국종축개량협회에 혈통등록 되어 있는 거세우를 선별하여 결측치 및 이상치를 제거하고 도축월령이 27~32개월 이외의 기록은 분석에서 제외한 후, 1,391,141두의 도체 자료를 분석에 이용하였다. 이용된 형질은 도체중(Carcass Weight, CW), 등심단면적(Eye Muscle Area, EMA), 등지방두께(Backfat Thickness, BF) 및 근내지방도(Marbling Score, MS)의 4개 형질을 고려하였다. Random Sampling 10 반복되어 추출된 Data 1의 도체중, 등심단면적, 등지방두께 및 근내지방도의 개량추세에 대한 회귀계수는 매년 평균 0.44㎏, 0.197㎠, -0.051㎜ 및 0.034점으로 나타났으며, 도축성적을 보유한 전체 개체의 자료로 구성된 Data 2에서는 각각 0.35㎏, 0.22㎠, 0.06㎜ 및 0.04점의 개량추세를 보였다. Data 2에서 씨수소의 개량추세는 1.54㎏, 0.343㎠, -0.045㎜ 및 0.050점의 추세를 보였으며 암소와 씨수소 간에는 1.19㎏, 0.119㎠, -0.014㎜ 및 0.010점의 차이를 보였다. 유전적 개량량을 확인하기 위하여 육종가의 표준편차를 이용하였으며, 암소의 선발강도는 본 연구에서 보고한 암소의 후대 거세우 기록 빈도 및 비율을 통해 계산하였다. 한우 암소의 선발 시기를 3산차 이전을 기준으로 하는 것과 4산차 이후를 기준으로 하는 것으로 나눠서 선발강도를 적용하였다. 그 결과, 암소의 선발 시기를 3산차 이전으로 했을 때 세대당 유전적 개량량은 도체중, 등심단면적, 등지방두께 및 근내지방도에서 각각 5.04㎏, 1.31㎠, 0.71㎜ 및 0.32점으로 나타났다. 이러한 결과를 바탕으로 현재 한우 암소집단에서 정확한 육종가를 추정하고, 유전적 개량량을 높이기 위해서는 후대의 기록을 높이기 위한 육종 계획이 필요할 것으로 판단된다.

본 연구는 한우농가에서 직접 사육되어 도축되어진 한우 거세우 전체의 도축성적 및 혈통자료를 수집하여 한우 암소의 유전능력평가를 위한 유전모수를 추정하고 농가에서 직접적으로 활용 가능한 유전능력 추정을 위한 기초자료로 제공하고자 하였다. 본 연구를 위해 검증된 970,141두의 도축기록으로부터 60,000두 이상의 표현형 표본을 추출하기 위해 전체 4,040농가 중 600농가를 단순임의추출(Simple Random Sampling)하여 선정된 농가의 도축기록을 모두 추출하는 방식으로 10회 반복하여 표본을 생성하였다. 본 연구에서 추정된 도체형질에 대한 유전력은 도체중에서 0.24-0.30, 등심단면적에서 0.24-0.31, 등지방두께에서 0.31-0.39, 근내지방도에서 0.38-0.58로 추정되었으며, 10회 반복 추정된 유전력의 평균값은 도체중, 등심단면적, 등지방두께 및 근내지방도에서 각각 0.28, 0.28, 0.35 및 0.48로 추정되었다. 추정된 결과가 기존에 한우에서 보고된 유전력에 비해 다소 낮게 추정되었으나 실제 농가에서 사육되어 도축된 전체 자료가 표본이 된 만큼 본 연구 결과는 전국단위의 도축자료를 이용한 결과로서 암소개량을 위해 직접적으로 활용 가능한 자료가 될 수 있을 것으로 기대된다.

The objectives of this study were to estimate genetic parameters and breeding values of four carcass traits of the Hanwoo cattle breed: carcass weight (CWT), back fat thickness (BFT), eye-muscle area (EMA), and marbling score (MAR). Genetic parameters and breeding values were estimated based on data (“estimating dataset”) collected from September 2004 to March 2019. Predictability of parental breeding value estimates (EBVs) for the performances of progeny of the control group was evaluated on another dataset (“testing dataset”) using linear model equations involving parental EBVs classified into sex and age groups. The parental EBVs of animals in the testing dataset were traced by pedigree relationships of animals in the estimating dataset. Heritability estimates of CWT, BFT, EMA, and MAR were 0.53, 0.43, 0.38, and 0.54, respectively. Genetic correlation coefficients of CWT with BFT, EMA, and MAR were +0.32, +0.59, and +0.11, respectively. Environmental correlation coefficients of CWT with BFT, EMA, and MAR were +0.46, +0.55, and +0.29, respectively. In the testing dataset, partial regression coefficients of phenotypic values of progeny on sire EBVs ranged from +0.43 to +0.60 depending on traits fit into the models, while those on dam EBVs ranged from +0.54 to +0.67. All partial regression coefficients were statistically significant and were approximated to the expected value of +0.5. Together, these values validate the use of parental EBVs for predicting progeny carcass phenotypes in the Hanwoo herd.

This study was conducted to examine the oocyte recovery efficiency through having an OPU session once and twice a week. Also, the oocyte recovery efficiency was examined by using OPU after two and three months of rest period. Six cows were used for oocytes collection and were randomly divided into two groups. In experiment 1, OPU sessions were conducted once and twice a week to collect oocytes. The collected oocytes between once and twice OPU groups were classified into four groups (grade 1, 2, 3 and 4) according to the quality of cumulus cells and ooplasm. Based on the result, the percentage of collected oocytes per aspirated follicle number was similar between once and twice OPU session groups (65.5 ± 1.9 and 68.7 ± 1.4 vs.). However, the percentage of grade 1 oocytes from the twice OPU session group was significantly high compared with that of the once a week OPU session group (25.3 ± 0.9 and 32.5 ± 1.2% vs. once and twice session group, respectively, p < 0.05). In experiment 2, the group with three months of rest period tended to have a high percentage of collected oocyte compared with the group with two months of rest period (64.6 and 70.9% vs. 2 and 3 months rest group, respectively, p = 0.62). The percentage of grade 4 in the group with three months of rest period was significantly low compared with the group with two months of rest period group (27.3 and 36.5% vs. two and three months rest group, respectively, p = 0.05). In conclusion, twice a week OPU session is suitable for collection of high quality oocytes by using OPU, and three months of rest period is needed for the recovery of oocyte quality of a donor cow.

The objective of this study was to investigate the effects of dry-aging and wet-aging conditions on the chemical composition, meat quality traits (color, water holding capacity, cooking loss, WBSF and pH) and shelf-life TBARS (2-thiobarbituric acid reactive substances) and VBN (volatile basic nitrogen) of loin (M. longissimus thoracis), sirloin (M. glutaeusmedus) and top-round (M. semimembranosus) cuts of Hanwoo cows. The dry-aging condition (temperature ℃, relative humidity %) was done for 60 d as 2℃, 65％, 20 d＋2℃, 75％, 20 d＋4℃, 85％, 20 d while, the wet-aging was done for 60 d at 1℃, 85%. Results revealed that moisture content was significantly higher in the dry-aged samples than that of the wet-aged samples at 60 d (p<0.05). The a*- and b*-values were significantly higher in 3 cuts as compared with those treated with wet-aging condition. During the dry-aging time, the WHC significantly increased in the loin and sirloin and they were significantly higher than wet-aging condition at 40 d and 60 d (p<0.05). The WBSF values significantly decreased with increased aging time and there was no significant difference between two aging methods. The TBARS and VBN contents significantly increased with increased aging time for all the wet- and dry-aged cuts, and their levels still fell within the acceptable standard limit. Generally, the TBARS and VBN contents were significantly higher in the dry-aged cuts, probably due to the increased levels of protein and fatty acids oxidations. Based on the results obtained in the present study, it can be suggested that application of dry-aging method can improve the quality characteristics of beef.

Serum metabolites were analyzed to investigate relationship of pregnancy and non-pregnancy Hanwoo cows. Totally, 251 Hanwoo cows were used in the present study. Grazing was carried out for 5 months in the pasture. In barn feeding, concentrate 3.0 Kg (TDN 68%, CP 14%) and rice straw 6 kg(TDN 50%, CP 6.5%) were fed. For artificial insemination (AI), progesterone-supplying device (CIDR) was introduced to vagina of Hanwoo cows and 2.0 mL of GnRH. One week after introduction, CIDR was removed and 5.0 mL of PGF2α was injected intramuscularly. After 2.5 day, AI was accompanied by a 2 mL of GnRH intramuscular injection and a second AI was carried out 3.5 day. The pregnancy diagnosis was confirmed by rectal palpation about 90 days after AI. Blood samples were collected from the jugular vein after 3 hours of feeding. Analysis of serum metabolites was performed on six types of metabolites: glucose(mg/dl), cholesterol(mg/mL), BUN(mg/dl), AST(U/L), ALT(U/l), and nonessterified fatty acids(NEFA, uEq/L). The metabolic profile test was analyzed by analyzer (Hitachi, 7020, Japan). Pregnant and non-pregnant groups showed serum metabolites as follows. In 60 pregnant group: Glucose 88.9 ± 2.5, Cholesterol 149.8 ± 4.9, BUN 16.9 ± 0.4, AST 99.1 ± 2.6, ALT 35.9 ± 0.9 and NEFA 326.7 ± 15.7. In 43 non-pregnant cow group: Glucose 89.2 ± 3.3, Cholesterol 165.9 ± 4.6, BUN 17.4 ± 0.6, AST 108.9 ± 0.6, ALT 37.8 ± 1.0 and NEFA 419.2 ± 32.8. Cholesterol, AST and NEFA levels in non-pregnant cows were significantly higher than those in pregnant cows (P<0.05). In sum of grazing and barn feeding group was totally 148 cows. Seventy nine pregnant cows showed high glucose and low NEFA levels compared to 69 non-pregnant cows (P<0.05). In conclusion, pregnant group showed high level of glucose and low level of cholesterol, NEFA. Further study needed to obtain more accurate level of metabolites in serum for pregnant and non-pregnant cows.

This study was conducted to ameliorate the productive performance of Hanwoo cow using hill pasture grazing system. Twenty seven animals aged 9 were designed to divide with 3 groups which were Control (restricted concentrate and hay for 5 months), T1 (restricted concentrate and pasture grazing ad libitum for 5 months) and T2 (restricted concentrate, 30 g/head of mineral nutrients and pasture grazing ad libitum for 5 months). Average daily gains increased higher in the order of T2, Control and T1. The conception rate of Control, T1 and T2 after artificial insemination during post-grazing period were 88.9%, 100%, 100%, respectively. In conclusion, the results indicated that hill pasture grazing system might enhance not only the productive performance of Hanwoo cow but also profit for conventional feeding system.

Early detection of Hanwoo cow’s estrus is an important issue in the management of group-housed livestock. In particular, failure to detect estrus in a timely and accurate way can become a limiting factor in achieving efficient reproductive performance. Although a rich variety of methods has been introduced for the detection of estrus, a more accurate and practical method is still required. The behavior of 50 estrus and 100 non estrus Hanwoo cows was video recorded and analysed in 2 Korean native cattle farm. All 50 estrus cattle (100%) showed the mounting or mounted behavior, but only 5 of 100 non estrus cattle (5%) showed the mounting or mounted behavior. One hundred and fifty Hanwoo cows with an age between 2 to 5 years that were expected to come into estrus within 3 days were randomly assigned to each compartment for the estrus group. The heated cows were video recorded for about 24 hours until after post estrus. The results showed that Hanwoo cows can be considered on estrus when it stand immobile during mounted by any other cow in more than or equal to 3.15 s and 3.22 s in chest-tail head mount and head-above back mount and that occurs consecutively at least three times within 876.4 s interval. The algorithm was also developed using the thresholds of the mount duration, mount interval and consecutive occurrence number. The Hanwoo cow’s estrus detection system using IR sensor (CEDSIRS) was composed of IR sensors, a controller, a CPU, a mobile, and so on. If total COUNT numbers per hour was above 1 and it was maintained more than 7 hours, we determined that a cow was in estrus and 16 h past the time from the first estrus detection was regarded as optimum AI time. The 55 of 57 estrus cows (96.5 %) were detected to estrus. Only 5 of 57 cows detected to estrus (8.8%) were decided to weak estrus and 2 of them were not detected. The total conception rate was 85.7%. The estimated price of CEDSIRS is 3,000,000 Won. Therefore, CEDSIRS will improve largely the average conception rate and economic benefits of Hanwoo cow farms.

본 연구는 지구온난화 시 예상되는 고온기를 대비하여 고온 및 사료 에너지 급여 수준이 한우 번식우 영양소 소화율에 미치는 영향을 규명하고 고온 스트레스 시 한우 번식우의 영양소 요구량을 설정하고자 수행하였다. 시험은 한우 번식우 4두(평균체중 491±85.6kg)를 공시하였고, 시험구는 고온 및 사료 에너지 급여 수준에 따라 4 시험구(한국가축사양표준 한우 번식우 유지요구량 TDN의 100%(대조구), 고온 처리 및 TDN 100%(T100), TDN 115%(T115), TDN 130%(T130))로 나누어 개체별 대사케이지에 4×4 Latin square design으로 배치하여, 각 period당 21일씩 대사시험을 실시하였다. 대조구는 온도 24℃, 습도 60%(온습도지수(THI)=71.46), 나머지 3개 처리구는 온도 30℃, 습도 70%(THI=81.38)로 설정하였다. 외관상 건물소화율은 대조구와 T100구가 각각 81.64와 81.39%로 T115(78.23%), T130구(78.15%)보다 유의적으로 높게 나타났다(p<0.05). 대조구 대비 혈중 thyroxine, glucose 및 BUN 함량은 T100구에서 수치적 감소가 나타났으나 T115 및 T130구에서 다시 증가하는 결과가 나타났다. 고온처리구의 일당증체량을 기준으로 한우 번식우 유지를 위한 TDN 요구량 산정식 (Y=0.2097X+111.2428)을 도출하였고, 이는 지구온난화(고온기) 시 유지를 위한 한우 번식우 TDN 요구량은 현재 한국가축사양표준에서 제시된 요구량 대비, 11.24%를 증량 급여해야 함을 의미한다.

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.

본 연구는 다양한 사료들을 유지수준에서 섭취한 한우 암소 경산우의 에너지 대사 시험의 결과로 부터 섭취에너지 균형과 메탄배출계수를 구하였다. 오차드그라스(orchard grass) 위주의 혼합목건초 섭취 7두, 혼합목건초의 30~50% 를 볏짚으로 대체한 12두, 혼합목건초와 볏짚에 밀기울 (wheat bran) 1 kg 추가급여한 6두, 총 25 개체의 대사실험 성적을 분석하였다. 실험축은 10일간 대사틀에서 개체별로 각각의 실험사료 적응 및 7일간 분 뇨 시료채취 후, indirect respiratory chamber 1대에 교대로 수용되어 1일간 호흡대사 실험이 이루어졌다. 혼합목건초 단독 급여구와 비교하여 나머지 두 처리구의 평균 건물섭취량은 약 11%, 15% 높았으나 통계적인 유의성은 없었고, gross energy (GE) 섭취량도 차이가 없었다. 총 섭취에너지 중 메탄으로 손실된 에너지 비율인 메탄전변율(methane conversion rate, Ym)과 메탄배출계수(emission factor, kg/head/year)도 각각 0.055~0.062 (평균 0.058)와 33.6~38.6(평균 35.2) 범위로 처리간 유의성이 없었다. 본 실험에서는 혼합목건초를 볏짚으로 대체하거나 또는 밀기울 추가급여에 의한 메탄발생량 차이가 없었으나, 메탄발생량을 줄일 수 있는 것으로 알려진 양질 조사료 급여효과 연구는 축산현장의 온실가스 감축 사업 참여가 가능한 분야이기 때문에 추가 연구들을 통해 시급히 증명되어져야 된다고 판단된다.

The recent development in genetic assisted selection (combining traditional- and genome assisted selection method) and reproduction technologies will allow multiplying elite cow in Hanwoo small farm. This review describes the new context and corresponding needs for genome assisted selection schemes and how reproductive technologies can be incorporated to get more genetic gain for cow genetic improvement in Hanwoo. New improved massive phenotypes and pedigree information are being generated from commercial farm sector and these are allowing to do genetic evaluation using BLUP to get elite cows in Korea. Moreover cattle genome information can now be incorporated into breeding program. In this context, this review will discuss about combining the reproductive techniques (Multiple Ovulation Embryo Transfer; MOET) and genome assisted selection method to get more genetic gain in Hanwoo breeding program. Finally, how these technologies can be used for multiplication of elite cow in small farm was discussed.

This study was conducted to investigate the effect of age on the oxidative stability of Hanwoo (Korean cattle) cow beef. The samples of M. longissimus dorsi from 65 and 133 months-old-Hanwoo cows (4 and 3 heads, respectively) were stored at 4±0.2℃ for 9 days. The proximate composition, total myoglobin content, pH value, water-holding capacity and drip loss were not significantly affected by age. At day 9 of storage, the lipid oxidation (2-thiobarbituric acid reactive substances) was significantly (p<0.05) higher in beef from 133 months-old-cows than 65 months-old-cows. Lower (p<0.05) oxymyoglobin concentration and R630-R580 value and higher (p<0.05) metmyoglobin concentration were observed in beef from 133 months-old-cows at day 9 of storage than 65 months-old-cows. The CIE a*, b* and C* values were significantly (p<0.05) lowered in beef from 133 months-old-cows at day 9 of storage than 65 months-old-cows. It could be concluded that old age decreased the lipid oxidation stability and myoglobin oxidation stability in Hanwoo cow beef.

The objective of this study was to investigate the influence of parity on chemical composition and meat quality of Hanwoo cows (n=74, 2-15 years old). The beef loin and top round muscle samples were obtained and divided by 3 groups of parity numbers (G1, 0; G2, 1-3; G3, 4-9 times). Loin and top round from G1 had significantly higher intramuscular fat contents and lower protein contents than those from G3 (p<0.05). There was no significant difference in collagen contents among 3 parity groups (p>0.05). In meat color, G1 was higher in a* values for loin and higher in L* and a* values for top round muscle (p<0.05). The loin from G1 had significantly lower cooking loss (%) than G3, however, there was no significant difference in water holding capacity among 3 parity groups. For top round muscle, G3 had significantly higher Warner-Bratzler shear force values and lower water holding capacity values than G1 (p<0.05). In fatty acid composition, G1 had significantly higher C18:1n7 and C18:1n9 contents for loin, and it had significantly higher C16:1n7 and C18:1n7 contents for top round than those of the other groups (p<0.05). In free amino acid composition, alanine was highest and followed by glutamine, phenylalanine, isoleucine, proline, glycine, methionine. In conclusion, the parity conditions influenced on chemical composition and meat quality depending on different cut of Hanwoo cows, and the parity numbers were related with the age of cows.

This study was carried out to investigate artificial insemination (AI) failure status and frozen semen characteristics in Korean proven bulls‘ number (KPN) semen used for AI of Hanwoo cows in Gangwon East region (Gangneung, Donghae, Taebaek, Samcheok, Sokcho, Yangyang, Goseong). Among semen used for AI, AI failure rate showed lowest at KPN506 (27.6%), whereas highest at KPN593 (77.2%). Correlations of AI failure in between Korean proven bulls semen and cows was 0.2941, which means that AI failure rate of Korean proven bulls semen may have respectable effect on reproduction of Hanwoo cow. In addition, present study was conducted to investigate spermatozoal viability rate, ruptured acrosome rate and active mitochondria in frozen Korean proven bulls semen with flow cytometry. The semen of KPN593 showed significantly (p<0.05) higher viability rate in KPN593 (30.49%) than that in KPN637 (37.34%). Furthermore, percentage of ruptured acrosome was lower in KPN637 as 21.37% than in KPN637 (21.37%), but it was not statistically significant. In conclusion, these results indicate that choice of Korean proven bulls semen may correlate positively with conception rate in Hanwoo cow. Therefore, KPN with high AI failure rate might be avoid to increase conception rate and characteristics of frozen semen might be evaluated before its use for AI.

This study was carried out to investigate the effect of muscle part and aging period on free amino acids and aroma compounds of Hanwoo (Korean cattle) cow beef. The M. longissimus (ML) and M. semitendinosus (MS) from 101 mon-old-cows were aged at 2℃ for 14 d. The free amino acids concentration increased in both ML and MS on 14 d of aging. In ML, asparagine, glutamine, histidine, glycine, threonine, arginine, tyrosine, phenylalanine, isoleucine, leucine and lysine were significantly (p<0.05) higher than those in MS. Varieties of aldehydes, ketones, alcohols, hydrocarbons, nitrogen and sulfur compounds were detected in both ML and MS and majority of these compounds showed increasing trend on aging. The ML had higher 14 aldehydes (acetaldehyde, 2-methylpropanal, 3-methylbutanal, 2- methylbutanal, pentanal, hexanal, heptanal, E-2-heptanal, octanal, 2-octenal, 2-nonenal, E-2-decenal, E,E-2,4-decadienal and 2-undecenal), 5 ketones (2-propanone, 2,3-butanedione, 2-butanone, 2-heptanone and 2,3-octanedione), 4 alcohols (ethanol, 1-pentanol, 1-hexanol and 1-octanol), 3 hydrocarbons (3-ethyl-2-methyl-1,3-hexadiene, 3- methyldecane and 2,2-dimethyloctane) significantly (p<0.05) compared with MS. However, the MS had higher 5 nitrogen and sulfur compounds (methanethiol, dimethyldisulfide, fufural, 2,5-dimethylpyrazine and 2-octylfuran) significantly (p<0.05) compared with ML.