본 연구는 국내에서 생산된 주요 동계 사료작물인 청보리 및 청호밀 사일리지를 이용하여 거세 한우의 비육후기(25~30개월 령) 용으로 조제된 TMR의 소 체내 이용성을배합사료 및 볏짚으로 구성된 관행 사료와 비교하고자 반추위 누관이 장착된 소 3두를 이용하여 3 × 3 Latin squaredesign 방법으로 실시되었다. 시험동물에는 비육 후기용 배합사료 및 볏짚을 분리 급여하였거나 (대조구) 청보리 사일리지 TMR (BS-TMR) 또는 청호밀 사일리지 TMR (RSTMR)을 급여하였다. 전체 채취시간에 걸쳐 반추위액의pH, 암모니아 농도 및 총 휘발성지방산 농도는 시험사료간 차이가 없었다. Acetate (C2)의 조성 비율은 사료 급여후 1시간에서 청보리 사일리지를 섭취한 처리구 (BS-TMR)에서 낮은 (p<0.033) 값을 제외하고는 대부분의 채취시간에서 시험사료 간 차이가 없었다. Propionate (C3) 및 butyrate조성비율과 C2/C3 비율 역시 모든 채취시간에서 시험사료간 차이가 없었다. 사료 내 주요 성분의 반추위 유효분해율과 전장소화율은 전체 시험사료 간은 물론 BS-TMR과RS-TMR 간에도 차이가 없는 것으로 나타났다. 본 대사시험 결과로 미루어보아 청보리 및 청호밀로 제조된 TMR의급여 가치가 배합사료 및 볏짚의 분리급여와 차이가 없는것으로 여겨진다.

This study was conducted to determine the growth performance and carcass characteristics of fattening Hanwoo heifers slaughtered at different ages. Twenty one Hanwoo heifers were randomly allocated to three groups (32, 36 and 40 months age), with 7 steers each, respectively. In the result, initial and final body weights were 125.6 and 651.0 kg, respectively. Average daily gain was significantly low at final stage compared with other growth stages (p<0.05). Dry matter intake was the peak at the intermediate fattening stage (p<0.05). The feed conversion ratio was significantly lower at growing stage compared to other stages (p<0.05). In yield traits, carcass weight was greater in 40 months age group compared to other groups (p<0.05). Yield index was greater in 32 months group compared to 40 months of age (p<0.05). Marbling score, meat color, fat color, texture, and maturity were not different among groups (p>0.05). However, marbling score tended to be increased in 40 months age group (5.9) compared to other groups. The appearance rate (%) of meat quality grade more than 1+ was greater at 40 months old group than other groups.

The study was conducted to investigate the comparison of pregnancy rate and transferable embryos produced by genetically superior Korean cows (Hanwoo) of livestock farms. Eighteen Hanwoo donors were superovulated with gonadotropin for 4 days combined with Progesterone Releasing Intravaginal. Embryos were recovered 7 days after the second insemination by flushing the uterus with embryo collection medium. No differences were observed in the efficiency of rate of superovulation in groups A (low nutrition) and B (highnutrition) it was observed to be 100.0% and 87.5%, respectively. The mean numbers of total embryos were 10.8±3.4 and 8.9±2.5, and transferable embryos were 7.5±3.3 and 4.0±1.5 in groups A and B, respectively. The pregnancy rates after embryo transfer were 23.5%, 20.0%, C 80.0% and 55.6% in farm A, B, C, and D, respectively. In conclusion, results suggest that superovulation could be used quite effectively to raise superior Hanwooembryos. However, physical and biological condition of recipients greatly affects the rate of pregnancy.

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.

Body condition score (BCS) is a useful management tool for distinguishing differences in nutritional needs of cows in the herd. Although it is not always possible to quantify the nutrient content of the feed supplied to the donor cow, the nutritional status can be determined by the BCS. The objective of this study was to evaluate in vivo embryo production, return to estrous of donor and pregnancy rate of recipients following BCS in Hanwoo superovulation. Sixty nine 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. The results obtained were as follows: No differences were observed in the efficiency of superovulation rates regardless of BCS (≦2.0, 2.5 to 3.0, and ≧3.5). The mean number of total embryos was each 5.20±0.86, 11.56±1.04, and 6.23±1.07. The mean number of transferable embryo from ≦2.0, 2.5 to 3.0, and ≧3.5 of BCS was 2.60±0.87, 7.94±0.89, and 4.75±1.32, respectively (p<0.05). Return to estrous regardless of donor BCS was no difference. The pregnancy rates of recipient were BCS ≦2.0 11.76%, 2.5 to 3.0 40.79%, and ≧3.5 11.11%, following transfer of fresh embryos produced in vivo, respectively. These results indicate that if the Hanwoo with BCS 2.5 to 3.3 are used for donor and recipient, the embryo production and the conception rate will be greater.

근내지방도(IMF)가 한우육의 품질 및 기능성분에 미치는 영향을 조사하기 위하여, 250두의 한우를 근내지방 함량 에 따라 Low(<14%, n=96), Medium(14～17%, n=83), High(>17%; n=71) 세 그룹으로 분류하고, 7일간 숙성 후 등심육의 품질 및 기능성분을 분석하였다. 한우 등심육의 수분 함량은 IMF와 반비례하였으며, High IMF 그룹은 Low IMP 그룹 에 비하여 낮은 드립 감량을 나타내었다. 기능성 didpeptide 함량은 IMF에 따라 유의적 차이가 없었으나, High IMF 그룹은 다른 그룹보다 낮은 inosine monophosphate, 높은 hypoxanthine, 낮은 histidine 함량은 나타내었다. 불포화지방산 의 비율은 IMF에 따라 유의적 차이가 없었다. 저지방육의 건강지향적 가치를 고려할 때 지나친 IMF를 목표로 하는 육종 및 사양은 지양되어야 할 것으로 판단되었다.

겨울철에 한우의 추위 스트레스를 경감하기 위하여 개방한우사의 북측 면에 윈치커튼 을 설치하여 차가운 북서풍 또는 북풍을 막아주고 있으나 윈치커튼의 최소 개방 면적 기 준이 마련되지 않은 실정이다. 따라서 본 연구는 한우의 추위 스트레스를 경감하기 위한 북측 윈치커튼의 최소 개방 면적 기준을 마련하기 위하여 수행되었다. 우리나라의 겨울 철 평균 풍속이 2 m/s 정도 되기 때문에 표준 개방한우사를 대상으로 1, 2 및 3 m/s의 풍속을 기준으로 북측 윈치커튼의 최소 개방 면적을 결정하고자 computational fluid dynamics(CFD) 시뮬레이션을 실시하였다. CFD 시뮬레이션 결과에 의하면, 폭이 30 m 인 표준 개방한우사의 경우 북측 윈치커튼의 최소 개방 면적은 10∼15 cm로 나타났다.

This study was carried out to investigate the effects of stocking density on eating and ruminating behavior of Hanwoo steers (Bos taurus coreanae) in the finishing period. A total of 30 finishing Hanwoo steers (631.3 ± 11.4 kg, 25 months old) were allocated to one of four stocking density groups comprising 1, 2, 3, and 4 steers per 32 m2 pen [G1 (32 m2), G2 (16 m2), G3 (10.7 m2) and G4 (8 m2), respectively] in triplicate. Eating, rumination behaviors, as well as dry matter intake of steers were measured, and the results were subjected to analysis of variance with stocking density as the main effect. The results of eating behaviors over 48 hours are summarized as follows: Total intake was significantly (p<0.01) higher in G1, G2, and G3 compared to G4. Eating time was not different among the treatments, whereas ruminating time increased in the order of G1 > G2 > G3 > G4 (p<0.01). However, resting time and chewing time (sum of eating and ruminating) were not significantly different among the treatments. Number of boluses and number of total chews were highest in G1 (p<0.01), whereas number of chews per bolus was highest in G3 (p<0.01). Ruminating time per bolus as well as number of boluses per minute was not significantly different among the treatments. Number of defecations was higher in G1 and G2 animals compared to G3 and G4 animals (p<0.01). However, stocking density had no effect on drinking or urination. In conclusion, increasing stocking density (i.e. G4) per pen decreased voluntary intake, ruminating time, and total chewing number in the finishing period of Hanwoo steers. However, care must be taken in discussing stocking density in the present study as the space allowance per animal was satisfactory to meet the current animal welfare regulation in Korea and in Europe, although the beef production system in Korea is more intensive than in Europe.

A study was conducted to determine the dietary effects of Na-bentonite (NaB) and probiotics on meat characteristics and health of Hanwoo steers fed rice straw as a sole roughage source. A total of 24 growing Hanwoo steers (avg BW 232 kg) were assigned to two treatments which included a control diet (concentrate mix and rice straw) and a treatment diet (control diet + 0.5-1.0% NaB + 0.5-1.0% probiotics. The diets were fed for 22 months up to the time the animals were slaughtered. Dietary treatment increased (p<0.05) concentrations of trace minerals such as Zn, Cu, and Fe in the longissimus muscle compared to the control. The treatment diet did not affect cold carcass weight, yield traits such as backfat thickness, longissimus muscle area, yield index, yield grade and quality traits such as marbling score, meat color, fat color, texture, maturity and quality grade. Blood profiles of growing steers were within the normal ranges for healthy cattle. In conclusion, feeding a combination of clay mineral and probiotics to Hanwoo steers fed rice straw as a sole roughage source could have a desirable effect on improving trace mineral retention in longissimus muscle without any deleterious effects on carcass traits of steers.

The present study was to assess the in vitro viability and sexing rate of bovine embryos. Blastocysts were harvested on day 7～9 day after insemination(in vitro and in vivo), and the sex of the embryos was examined using the LAMP method. Embryo cell biopsy was carried out in a 80 μl drop Ca2+, Mg2+ free D-PBS and, biopsied embryos viability were evaluated after more 12 h culture in IVMD culture medium. The formation of recovered embryo to expanded and hatching stages had ensued in higher of sexed embryo in vivo than in vitro (100% vs. 89%, p<0.05), and in vitro, the rates of degeneration after sexing were significantly (p<0.05) higher in vitro than in vivo(11% vs. 0.0%). The rates of the predicted sex were female 61% vs. 56%, and male 39% vs. 44% in vivo and in vitro, respectively. The rates of survival following different biopsy methods were seen between punching and bisection method in vivo and in vitro (100% vs. 89% and 100% vs, 78% respectively). Biopsy method by punching was significantly (p<0.05) higher than bisection between produced embryos in vivo and in vitro. The present data indicate that with microblade after punching for embryo sexing results in high incidence of survivability on development after embryo biopsy. It is also suggested that LAMP-based embryo sexing suitable for field applications.

The technique of SCNT is now well established but still remains inefficient. The in vitro development of SCNT embryos is dependent upon numerous factors including the recipient cytoplast and karyoplast. Above all, the metaphase of the second meiotic division (MII)　oocytes have typically become the recipient of choice. Generally high level of MPF present in MII oocytes induces the transferred nucleus to enter mitotic division precociously and causes NEBD and PCC, which may be the critical role for nuclear reprogramming. In the present study we investigated the in vitro development and pregnancy of White-Hanwoo SCNT embryos treated with caffeine (a protein kinase phosphatase inhibitor). As results, the treatment of 10 mM caffeine for 6 h significantly increased MPF activity in bovine oocytes but does not affect the developmental competence to the blastocyst stage in bovine SCNT embryos. However, a significant increase in the mean cell number of blastocysts and the frequency of pregnant on 150 days of White-Hanwoo SCNT embryos produced using caffeine treated cytoplasts was observed. These results indicated that the recipient cytoplast treated with caffeine for a short period prior to reconstruction of SCNT embryos is able to increase the frequency of pregnancy in cow.

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.

이 논문은 한육우 사육두수 주기를 분석하고 이 주기를 기초로 한육우 사육두수를 예측하였다. 이를 위해 일정한 주기를 가지고 정점과 저점을 반복하는 싸인함수를 활용하였다. 과거 한육우 사육두수의 주기는 짧게는 5년부터 길게는 12년까지의 패턴을 보여주었고, 이러한 주기는 시간이 흐름에 따라 점차 길어지는 양상을 보여주고 있다. 싸인함수를 활용하여 한육우 사육두수를 추정한 결과, 모형의 적합도가 0.95로 매우 높게 나타났다. 이 모형을 이용하여 한육우 사육두수를 예측한 결과, 사육주기에 따라 약간의 차이가 나지만 저점의 사육두수는 160∼180만두 정도이고 정점의 사육두수는 320만두∼370만두 수준으로 예측되었다. 이러한 예측결과는 사육두수 불안정성에 따른 농가 소득 불안정성을 내포하고 있어 그에 따르는 적절한 정책이 필요함을 시사한다.

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.