Background: Sperm quality and the number of sperm introduced into the uterus during artificial insemination (AI) are pivotal factors influencing pregnancy outcomes. However, there have been no reports on the relationship between sperm concentration at AI and sperm quality in Hanwoo cattle. In this study, we examined sperm quality and pregnancy rates after AI using sperm inseminated at different concentrations. Methods: We evaluated the motility, viability, and acrosomal membrane integrity of sperm at different concentrations (10, 15, 18, and 20 million sperm/straw) in 0.5-mL straws. Subsequently, we compared the pregnancy rates after AI with different sperm concentrations. Results: After freeze-thawing, sperm at the assessed concentrations showed similar viability and acrosomal membrane integrity. After AI, cattle in the 10 million group had significantly lower pregnancy rates compared to those in the 18 and 20 million groups. Conversely, there were no statistically significant variances observed between cattle in the 10 and 15 million groups. Conclusions: Sperm at concentrations of 10, 15, 18 and 20 million per straw exhibited comparable motility, viability, and acrosomal membrane integrity. However, a concentration of at least 18 million sperm per straw is required to achieve a consistent rate of pregnancy rate in Hanwoo cattle after AI.

This study divided the area capable of producing domestic forage into grazing pasture, hay production area, and silage crop area, calculated the required area according to the forage production volume, and examined whether self-sufficiency in forage leads to cost savings. When the self-sufficiency rate of forage for dairy cows and Hanwoo is 80%, the improvement in profitability per heaf ranges from 3% to 9%, typically around 5%, which is considered a significant benefit for both corporate and individual businesses. The average profit per ranch is expected to increase about KRW 50 million per year, and the country as a whole is expected to reduce forage costs by KRW 0.9 trillion per year. Recently, efforts are being made by the government and local authorities to cultivate summer forage at the rice fields for improving self-sufficiency in forage feed to stabilize rice supply and demand. Furthermore, it is also necessary to conduct research on reducing the cost of concentrated feed and TMR (Total mixed ration).

Background: Recently, the single-step genomic best linear unbiased prediction (ssGBLUP) method, which incorporates not only genomic information but also phenotypic information of pedigree, is under study. In this study, we performed a ssGBLUP analysis on a commercial Hanwoo population using phenotypic, genotypic, and pedigree data. Methods: The test population comprised Hanwoo 1,740 heads raised in four regions of Korea, while the reference population used Hanwoo 18,499 heads raised across the country and two-generation pedigree data. Analysis was performed using genotype data generated by the Hanwoo 50 K SNP beadchip. Results: The mean Genome estimated breeding values (GEBVs) estimated using the ssGBLUP methods for carcass weight (CWT), eye muscle area (EMA), back fat thickness (BFT), and marbling score (MS) were 7.348, 1.515, -0.355, and 0.040, respectively, while the accuracy of each trait was 0.749, 0.733, 0.769, and 0.768, respectively. When the correlation analysis between the GEBVs as a result of this study and the actual slaughter performance was confirmed, CWT, EMA, BFT, and MS were reported to be 0.519, 0.435, 0.444, and 0.543, respectively. Conclusions: Our results suggest that the ssGBLUP method enables a more accurate evaluation because it conducts a genetic evaluation of an individual using not only genotype information but also phenotypic information of the pedigree. Individual evaluation using the ssGBLUP method is considered effective for enhancing the genetic ability of farms and enabling accurate and rapid improvements. It is considered that if more pedigree information of reference population is collected for analysis, genetic ability can be evaluated more accurately.

Background: Estrus in cows can be detected through vaginal electrical resistance or conductivity. However, there are no studies measuring vaginal electrical resistance in Hanwoo cows. This study aims to measure the vaginal electrical resistance value in Hanwoo cows and compare it with estrus and ovulation. Methods: Vaginal electrical resistance values of 73 Hanwoo cows were measured before and after estrus at the Gyeongsangbuk-do Livestock Research Institute. Measurements were taken on days -6, -3, -2, -1, 0, 1, 2, 3, and 6 of artificial insemination. Large follicles and ovulation were confirmed using transvaginal ultrasonography. Results: The vaginal electrical resistance averaged 225.6 ± 6.3 Ω days before the artificial insemination date, decreasing until the day of artificial insemination. The average vaginal electrical resistance was 163.7 ± 4.6 Ω on the date of artificial insemination, and 188.8 ± 4.3 Ω one day after artificial insemination, when large follicles were observed. In addition, on the 6th day after artificial insemination, the vaginal electrical resistance averaged 231.4 ± 5.5, which was similar to the 6th day before artificial insemination (222.5 ± 6.3). Transvaginal ultrasonography showed that most of the cows ovulated one day after artificial insemination. Conclusions: The accuracy of estrus is high if the vaginal electrical resistance is measured for cows with confirmed estrus, making is a potentially useful for determining the timing of artificial insemination.

This study aimed to investigate the effects of amino acid complex additives, such as protected vitamin C (VC) or detoxified sulfur (DS), on the growth and metabolism of Hanwoo cattle under high-temperature conditions. Accordingly, farms in Temperature-Humidity Index (THI) regions ranging from 78 to 89 for over 100 days were selected. The experimental groups were control, T1 (lysine + methionine + VC, 50 g/head/day), and T2 (lysine + methionine + DS, 50 g/head/day) with 70, 77, and 71 animals each. The range of the THI for 115 days was 78-89, and this occurred in most of the experiment days. The results showed that there was no significant difference in rectal temperature among the groups. The body weight increased to 786.4 and 809.0kg in the T1 and T2 groups, respectively, compared to the control group (p<0.05). Linoleic acid showed a high result of 2.01% in the T1 group compared to the control group (p<0.05). Unsaturated fatty acids were higher at 55.70 and 56.54% in the T1 and T2 groups, respectively, compared to the control group (p<0.05), and the omega 6/3 ratio was reduced to 20.10% (p<0.05). These findings indicate that T1 has a positive impact on growth, meat quality, and fatty acid composition compared to the control group. In conclusion, amino acid complex with VC improved the body weight of Hanwoo steers and the unsaturated fatty acids and essential amino acids of their meat; however, further research is needed to clarify this impact on carcass performance.

γ-aminobutyric acid (GABA) is a natural stress-reducing substance and is actively used as a human health supplement. However, minimal research has been conducted on its use in cattle. This study was conducted to evaluate the effects of GABA on the growth performance, complete blood count, blood metabolites, and carcass characteristics of fattening Hanwoo steers. Twenty-one fattening steers were randomly assigned to one of three treatments: control (basal diet: concentrate feed + rice straw), T1 (basal diet + GABA supplement at 0.8% of feed/head/day), and T2 (basal diet + GABA supplement at 1.6% of feed/head/day). Feed intake and conversion ratio did not differ among the treatments. However, the average daily gain during the early fattening period increased linearly to 0.80 kg, 0.86 kg, and 0.92 kg in the control, T1, and T2 groups (p<0.05). Plasma γ-glutamyl transferase (37.5, 58.2, 42.8 U/ℓ) and creatinine (1.32, 1.34, 1.49 ㎎/㎗) levels in the GABA supplement group were increased compared to those in the control group. The carcass weight (422.7, 427.1, 454.1 kg), rib eye area (86.67, 92.57, 91.14 cm2), and marbling score (3.67, 4.29, 4.14) were numerically higher in the GABA supplement group than in the control group. Thus, GABA supplementation positively affected the average daily gain and carcass characteristics of Hanwoo steers. However, the effect of the GABA supplement level of GABA was small, and further research using rumen-protected coating technology on GABA is necessary.

한우에게 급여하는 사료 내 에너지원의 종류에 따라 반추위 미생물의 아미노산 조성에 차이가 있는지를 조사하고자 본 연구를 수행하였다. 국내 한우 비육우 사육에 주로 이용되는 에너지원 사료인 옥수수(T1), 생미강(T2), 소맥(T3) 그리고 소맥피(T4)로 반추위 환경과 유사한 연속식 배양기를 이용하여 72시간까지 배양을 진행하였다. 배양이 진행되는 동안 6시간 간격으로 배양액의 발효 성상을 확인하였으며 pH, NH3-N이 일정하게 유지되는 것을 확인하였으며, 배양 종료 시점인 72시간대에 미생물체 단백질 합성량(MPS), 미생물의 아미노산 조성 및 미생물 균총 변화를 분석하였다. 배양액의 pH는 모든 처리구에서 배양 기간동안 5.5~7.0을 유지하였다. Total VFA 농도는 T1이 23.13 mM으로 가장 낮았고, T4가 29.93 mM으로 가장 높았다(p<0.05). A (acetate) :P (propionate) 비율은 T1이 1.48로 가장 낮았으며, T4가 2.81로 가장 높게 나타났다 (p<0.05). Butyrate는 T1이 2.37 mM으로 가장 낮았으며, T2, T3 그리고 T4는 4.37~4.58 mM으로 차이가 없었다(p<0.05). MPS는 T2 (332.5 mg/L)와 T3 (320.2 mg/L)가 높았고 T1 (137.5 mg/L)와 T4 (154.2 mg/L)로 낮게 나타났다(p<0.05). DGGE band 분석결과 모든 처리구는 57.5 % 이하의 유사도가 나타났다. 미생물의 총 아미노산 함량은 T1 (31.59 %)과 T3 (31.33 %)가 가장 높았으며, T2 (20.09 %)가 가장 낮았다 (p<0.05). 이는 급여된 사료 내 총 아미노산 함량과 반대되는 결과로 나타났다. 따라서, 본 연구에서 한우 급여 에너지원 사료에 따른 반추위 내 미생물 발효 특성과 미생물체 단백질 합성량이 미생물 군집에 영향을 미치며 이에 따라 미생물의 총 아미노산 함량에 영향을 미친다는 것을 확인하였다.

본 연구는 국내의 한우 개량에 있어서 정확한 혈통 정보가 중요해짐에 따라 고밀도 Single Nucleotide Polymorphism (SNP) chip의 SNP 정보들을 활용한 친자 확인으로 혈통 정보의 신뢰도 향상에 기여하고자 실시하였다. 이미 혈통 정보가 확인되고 Microsatellite (MS) 유전자형으로 친자 여부가 확인된 14개의 가계, 318두로 친자 확인 분석을 하였다. Call rate 100%인 마커들을 활용한 친자 확인 분석 결과, 9두가 모 부정, 19두가 완전 부정으로 총 28두가 부정으로 판정되었고, 이는 부모의 SNP 정보에서 나올 수 있는 조합과 다른 자식의 유전자형이 확인되었다. 이후, 친자 확인 정확도 향상을 위해 call rate와 minor allele frequency (MAF)를 기준으로 SNP 마커 수를 증가시켜 분석하였으나 부정으로 판정되는 개체들이 추가적으로 발생하였고, 이는 SNP 정보의 결측치 증가 및 자식의 유전자형 변이로 인한 것으로 판단된다. 따라서 고밀도 SNP chip을 활용한 친자 확인 분석에는 보다 신중한 접근이 필요하며, 본 연구 결과는 고밀도 SNP 정보를 이용한 친자 확인 연구에 있어서 기초자료로 활용될 수 있을 것으로 사료된다.

Background: Copy number variation (CNV) can be identified using next-generation sequencing and microarray technologies, the research on the analysis of its association with meat traits in livestock breeding has significantly increased in recent years. Hanwoo is an inherent species raised in the Republic of Korea. It is now considered one of the most economically important species and a major food source mainly used for meat (Hanwoo beef). Methods: In this study, CNVs and the relationship between the obtained CNV regions (CNVRs) can be identified in the Hanwoo steer samples (n = 473) using Illumina Hanwoo SNP 50K bead chip and bioinformatic tools, which were used to locate the required data and meat traits were investigated. The PennCNV software was used for the identification of CNVs, followed by the use of the CNV Ruler software for locating the different CNVRs. Furthermore, bioinformatics analysis was performed. Results: We found a total of 2,575 autosomal CNVs (933 losses, 1,642 gains) and 416 CNVRs (289 gains, 111 losses, and 16 mixed), which were established with ranged in size from 2,183 bp to 983,333 bp and 10,004 bp to 381,836 bp, respectively. Upon analyzing the restriction of minor alleles frequency > 0.05 for meat traits association, 6 CNVRs in the carcass weight, 2 CNVRs in the marbling score, 3 CNVRs in the backfat thickness, and 2 CNVRs in the longissimus muscle area were related to the meat traits. In addition, we identified an overlap of 347 CNVRs. Moreover, 3 CNVRs were determined to have a gene that affects meat quality. Conclusions: Our results confirmed the relationship between Hanwoo CNVR and meat traits, and the possibility of overlapping candidate genes, annotations, and quantitative trait loci that results depended on to contribute to the greater understanding of CNVs in Hanwoo and its role in genetic variation among cattle livestock.

Because multiple ovulation embryo transfer (MOET) in cattle includes several benefits such as wide spreading of genetically superior offspring for long distance, this biotechnological method has been widely applied to Hanwoo. When the recipients are not stayed close after embryo recovery from donor, the embryos are moved to other farms via several vehicles (car, train, and airplane). However, air travel induces lesser oxygen level, increased vibration, lower air pressure, higher noise, and increased exposure of cosmic radiation to living things than ground level. It was still unknown that fresh embryos obtained from multiple ovulation of Hanwoo could maintain their fertility after being transported via air plane, the present case report introduced a clinical case of MOET in Hanwoo after shipping fresh embryos via air transportation. The donor was multi-ovulated via follicle-stimulating hormone series of injection, which was followed by a gonadotrophin-releasing hormone injection and artificial insemination twice. The embryos were recovered by the uterine flushing, packed in ministraws, transported to recipients for 6 h including 1 h air flight, and then transferred to the synchronized recipients. During pregnancy diagnosis of early gestation period, 5 of 7 recipients (71.4%) presented no heat signs and showed fetal sacs with fluid under transrectal ultrasonography. After normal gestation period, all recipients naturally delivered healthy calves (male n = 2 and female n = 3) without abortion, stillbirth, and premature birth. The present case report indicated that transportation of fresh embryos for MOET via domestic flight in Korea did not affect to their fertility.

This study has evaluated the genomic estimated breeding value (GEBV) of the commercial Hanwoo population using the genomic best linear unbiased prediction (GBLUP) method and genomic information. Furthermore, it analyzed the accuracy and realized accuracy of the GEBV. 1,740 heads of the Hanwoo population which were analyzed using a single nucleotide polymorphism (SNP) Chip has selected as the test population. For carcass weight (CWT), eye muscle area (EMA), back fat thickness (BFT), and marbling score (MS), the mean GEBVs estimated using the GBLUP method were 3.819, 0.740, -0.248, and 0.041, respectively and the accuracy of each trait was 0.743, 0.728, 0.737, and 0.765, respectively. The accuracy of the breeding value was affected by heritability. The accuracy was estimated to be low in EMA with low heritability and high in MS with high heritability. Realized accuracy values of 0.522, 0.404, 0.444, and 0.539 for CWT, EMA, BFT, and MS, respectively, showing the same pattern as the accuracy value. The results of this study suggest that the breeding value of each individual can be estimated with higher accuracy by estimating the GEBV using the genomic information of 18,499 reference populations. If this method is used and applied to individual selection in a commercial Hanwoo population, more precise and economical individual selection is possible. In addition, continuous verification of the GBLUP model and establishment of a reference population suitable for commercial Hanwoo populations in Korea will enable a more accurate evaluation of individuals.

This study was designed to evaluate the objective meat qualities of Hanwoo longissimus lumborum muscle after a period of long-term storage (40 days) in which conditions similar to those under which the meat would be stored for export to the Hong Kong beef market were simulated. Twelve LL muscles were sampled from animals slaughtered the previous day at a commercial beef export abattoir and assigned to one of three groups. Each group was subjected to a different packaging condition; Shrink film packed (SFP), vacuum packed (VP), or modified atmosphere packed (MAP)(O2/60%, CO2/40%). Objective meat qualities were assessed at day 1, 7, 21 and 40 of storage. Different Packaging conditions had no noticeable influence on cooking loss significantly. However, the moisture content in both the SFP and MAP groups tended to decline in a linear manner with storage periods throughout the 40 days period. Drip loss of MAP (5.68%) group was much higher in the SFP (3.18%) and VP (2.64%) groups at storage day 40. Redness (CIE a*) of meat color responded in a significant and completely different manner to each packaging method. Redness significantly (p<0.05) and continuously increased 17.51 at day 1 to 20.41 at day 40 in VP group, while MAP linearly dropped and ultimately reached 10.6 after 40 days of aging (p<0.05), at which point the meat had a brown color. Tests of Warner-Bratzler shear force (WBSF) indicated that the tenderness levels of the ready-for-export Hanwoo LL muscles were acceptable 7 days postmortem in the SFP and VP groups, however there was no significant difference between each group. Our gathered data suggests that the packaging method selected for export determines how well the objective qualities of the beef hold up, and indicate that VP is likely the most reliable method.

쇠고기 이력추적제는 소 개체마다 이력번호를 부여하여 수입쇠고기가 한우고기로 둔갑하는 사례를 막고, 소비자 에게 구입한 한우고기의 세부 이력 정보들을 제공하는 데 도움을 준다. 이번 연구는 2021년-2022년 서울지역 대형 축산물판매업소에서 유통되는 한우고기 344건에서 DNA 동일성 검사를 실시하여 이력번호 등 주요 표시정보들의 진위를 판별하였다. 그 결과 45건(13.1%)에서 이력번호가 불일치한 것으로 확인되었다. 불일치율은 2021년(14.7%) 에 비해 2022년(11.3%) 감소하였고, 도심서북권 20.7%, 동 북권 14.4%, 서남권 및 동남권 10.2% 순으로, 북부권 (16.9%)이 남부권(10.2%)에 비해 높게 나타났다. 또한 6개 브랜드 중 B사 및 D사는 이력관리가 양호한 반면, E사 및 A사는 이력관리가 취약한 것으로 확인되었고, 통계적 으로 유의한 결과 차이를 보였다(P<0.001). 이력번호 불일 치 시료의 실제 이력번호는 업소 내 입(출)고 거래내역 자 료를 근거로 조사하였고, 그 결과 실제 이력번호 확인율 은 53.9%에 불과하였으나, 확인된 범위 내에서 시료의 표 시정보 진위 판별 결과, 거짓 표시는 이력번호 13.1%, 성 별 2.9%, 도축장명 2.2%, 등급 1.6% 순으로 나타났고, 품종 (한우) 거짓 표시는 없었다. 거짓 표시 축산물의 유통 차 단을 위해 표시정보의 신속한 진위 판별이 중요하므로 업 소 내 이력번호가 기재된 날짜별 부분육 소분할 작업내역 작성을 의무화하는 법적 근거 마련이 필요하다. 본 연구 결과는 투명한 축산물 유통 거래 질서 정착을 위한 이력 관리 방향 설정에 참고자료로 활용하고자 한다.

South Korea has a temperate climate with four distinct seasons. However, summers are extremely hot and humid, which negatively affects industrial animal production. Hanwoo are native cattle that have traditionally been raised in the natural environment of Korea. The present study investigated the effects of birth and lactation season on the birth and weaning weights of Hanwoo calves. Data were collected from 100 local breeding farms between 2016 and 2021. A total of 56,970 (males, 29,530; females, 27,440) Hanwoo calves were classified according to sex or birth and weaning season (March–May, spring; June–August, summer; September– November, fall; and December–February, winter). The birth weight of Hanwoo calves differed according to the birth season. As such, birth weight of the summer-born calves was the lowest. Additionally, the 90-day weaning weight was positively correlated with birth weight. Interestingly, however, the 90-day weaning weight was not related to the birth season but was related to the 2-month seasonal effect during the lactation period. Furthermore, the 90-day weaning weight was the lowest during the summer lactation period. In the beef cattle industry, daily weight gain is an important economic characteristic related to feed efficiency and growth. Our findings will contribute the management of Hanwoo cattle and analysis of changes in economic characteristics due to high temperatures.

본 연구에서는 미생물 첨가에 따라 거세한우 비육우 분의 이화 학적 특성, 미생물 성상, 가스발생량 및 퇴비 부숙도에 미치는 영 향을 규명하고자 수행하였다. 이상의 결과를 종합하면, 4주 후,미생물 첨가구에서 수분, 유기물, 총질소 함량 및 pH가 낮았으며, 나머지 이화학적 특성에서는 차이가 나타나지 않았다. 유산균과 효모균 수는 증가하였으며, 대장균 수는 감소하였다. 12주 후, 미 생물 첨가구에서 유산균과 고초균 수는 높았으나, 수분, 효모 및 대장균 수는 낮게 낮았다. 하지만 암모니아, 황화수소 발생량과 퇴비 부숙도는 미생물 첨가에 의한 효과가 나타나지 않았다. 따라 서, 거세한우 분에 미생물을 첨가하면 유익균은 증가하고, 병원성 미생물은 감소하여, 비육우의 생산성은 증진될 것으로 사료되지 만, 가스 발생량 및 퇴비 부숙도에 대한 추가적인 연구는 지속적 으로 수행되어야 할 것으로 사료된다.

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.

반추위 미생물체 단백질의 아미노산 조성이 한우의 에 너지원 사료에 따라 차이가 있는지를 조사하고자 본 연구 가 수행되었다. 본 실험은 국내 한우 비육우 사육에 주로 이용되는 에너지원 사료인 옥수수(T1), 생미강(T2), 소맥 (T3), 소맥피(T4)를 이용하여 in vitro 반추위 발효실험을 진행하여 발효 24시간 후 배양액의 발효 성상, 미생물체 단백질 합성량(MPS), 미생물의 아미노산 조성 및 미생물 균총 변화를 분석하였다. 배양액의 pH는 T4가 6.02로 다 른 처리구들에 비해서 가장 높았으며, T1은 4.84로 가장 낮았다(p<0.05). Total VFA 농도는 T2가 96.80mM로 다른 처리구들에 비해서 가장 높았고, T1이 53.35mM로 가장 낮았다(p<0.05). 미생물체 단백질 합성량은 T3가 222.50g/L로 다른 처리구들에 비해서 높았으며(p<0.05), T1과 T4는 유의적인 차이는 없었지만 T1이 가장 낮았다. DGGE band 분석결과 모든 처리구는 57.5% 이하의 유사도를 나타내었으며, 급여되는 사료에 따라서 미생물 군집 이 다르게 나타났다. 미생물 내 총 아미노산 함량은 T3와 T4가 다른 처리구보다 높았다(p<0.05). 미생물의 아미노산 조성 중 대부분의 필수 아미노산은 T4가 다른 처리구들에 비해서 낮았다. 하지만 methionine은 다른 필수 아미노산 과 다르게 T4에서 가장 높았다(p<0.05). 곡류 사료 위주의 급여 시 결핍되기 쉬운 lysine은 모든 처리구에서 미생물 의 아미노산 조성이 8.05~8.98%의 범위에 있었다. 따라서, 본 연구에서 반추 가축 급여 에너지 사료원에 따른 반추 위 내 미생물 발효특성과 미생물 군집의 차이가 미생물의 아미노산 조성을 변화시킨다는 것을 확인하였다.

본 연구는 한우 암송아지 비육프로그램 개발을 위하여 약 8개월령 30두(평균 체중 233kg)에게 전 시험기간동안 한우 거세우 육성용 사료(CP 13.65%, TDN 72.7% 건물기 준)를 자유채식 또는, 제한급여(체중의 1.5%, 1.6%/일)를 시킨 후, 24개월령부터 출하 시(32개월령)까지는 자유 채 식시켰다. 본 시험에서 출하 시 체중은 685-702kg 이었으 며, 전 기간 평균 사료 섭취량(7.78–9.05kg/일)과 증체량 (0.58–0.64kg/일)은 자유채식구가 제한급여구보다 많았다 (p<0.05). 한우 미경산 암소의 배최장근 단면적은 평균 99.9cm2였으며, 도체중은 평균 407kg이었다. 조리 감량은 수분함량이 높고 보수력이 낮을수록 많았다(p<0.05). 등심 중 아미노산 함량은 glutamic acid, aspartic acid, lysine, leucine 순으로 높았으며, 지방산 중에는 oleic acid가 55.9 –58.7% 수준으로 자유채식구가 제한급여구보다 높았다 (p<0.05). 따라서 한우암소 비육 프로그램으로서, 한우 거세우 육 성용 TMR을 전 기간(6-32개월령) 동안 자유 채식시키면, 사료효율, 도체 성적 및 등심의 물리·화학적 특성에 있어 서도 우수한 결과를 나타낼 수 있을 것으로 판단된다.

본 연구에서는 거세방법에 따른 한우의 안심살(M. psoas major), 꽃등심살(M. longissimus thoracis) 및 우둔살(M. semimembranous)의 육질특 성과 지방산 조성을 조사하였다. 공시시료는 송아지가 7개월령에 도달하면, 외과적 수술방법을 통해 한쪽 고환을 제거한 반거세 한우(half-castration; HC) 9두와 양쪽 모두 제거한 완전거세 한우(complete-castration; CC) 8두를 이용하였다. 거세된 송아지는 24-26개월까지 동일한 조건에서 사육한 후 도축하고 3개 부위(안심살, 꽃등심살, 우둔살)를 채취하여 육질 분석하였다. 거세방법에 따른 그룹 간 지방함량은 HC 그룹이 2.97~11.06%로 CC 그룹보다 낮은 함량을 나타내었으며, 수분함량은 HC 그룹이 65.39~70.90%로 CC 그룹보다 높은 함량을 나타내었다(p<0.05). 3개 근육의 pH는 5.47~5.54 범위였으며, pH와 보수력은 거세방법에 따른 유의적인 차이는 나타나지 않았다(p>0.05). 육색은 L*값과 a*값에서 HC가 CC보다 낮게 나타났다(p<0.05). 가열감량과 전단력은 HC 그룹의 꽃등심살이 CC 그룹보다 높은 값을 나타내었다(p<0.05). 지방산 조성은 palmitic acid, palmitoleic acid, vaccenic acid, oleic acid, linoleic acid, linoleneic acid와 PUFA, n6에서 HC와 CC 그룹 간 유의적 차이가 나타났다(p<0.05). 특히, 지방산 조성에서 HC 그룹과 CC 그룹 모두 oleic acid가 가장 높은 함량을 나타내었다(p<0.05). 따라서 거세 방법은 한우육의 근육 내 지방, 육색, 연도와 같은 이화학적 특성과 지방산 조성에 영향을 미칠 수 있다고 사료된다.

The present study was conducted to examine the effect of soybean silage as a crude protein supplement for corn silage in the diet of Hanwoo steers. The first experiment was conducted to evaluate the effect of replacing corn silage with soybean silage at different levels on rumen fermentation characteristics in vitro. Commercially-purchased corn silage was replaced with 0, 4, 8, or 12% of soybean silage. Half gram of the substrate was added to 50 mL of buffer and rumen fluid from Hanwoo cows, and then incubated at 39°C for 0, 3, 6, 12, 24, and 48 h. At 24 h, the pH of the control (corn silage only) was lower (p<0.05) than that of soybeansupplemented silages, and the pH numerically increased along with increasing proportions of soybean silage. Other rumen parameters, including gas production, ammonia nitrogen, and total volatile fatty acids, were variable. However, they tended to increase with increasing proportions of soybean silage. In the second experiment, 60 Hanwoo steers were allocated to one of three dietary treatments, namely, CON (concentrate with Italian ryegrass), CS (concentrate with corn silage), CS4% (concentrate with corn silage and 4% of soybean silage). Animals were offered experimental diets for 110 days during the growing period and then finished with typified beef diets that were commercially available to evaluate the effect of soybean silage on animal performance and meat quality. With the soybean silage, the weight gain and feed efficiency of the animal were more significant than those of the other treatments during the growing period (p<0.05). However, the dietary treatments had little effect on meat quality except for meat color. In conclusion, corn silage mixed with soybean silage even at a lower level provided a greater ruminal environment and animal performances, particularly with increased carcass weight and feed efficiency during growing period.