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 study was performed to evaluate the effect of heat stress on the status of physiological responses, blood parameter, serum T3 and cortisol, and heat shock proteins (HSP 27, 70, and 90) of Hanwoo cattle. Six Hanwoo steers (242.8 ± 7.2 kg of BW) were housed in the climate-controlled respiration chambers. The experiment consisted of 7 days (control; 0 day) at thermoneutral (air temperature (Ta) of 15oC and relative humidity (RH) of 60%; temperature-humidity index (THI) = 64), and by 3 and 6 days (treatment groups) at heat stress (Ta of 35oC and RH of 60%; THI = 87). Body temperature of each parts (frank, rump, perineum and foot) and rectal temperature elevated in heat stress groups (3 days and 6 days) than the control group (0 day). Respiration rates increased in 3 days and 6 days (88.5 ± 0.96 bpm and 86.3 ± 0.63 bpm, respectively) from 0 days (39.5 ± 0.65 bpm). Feed intake significantly decreased in heat stress groups (3 days and 6 days, 3.7 ± 0.14 kg and 4.0 ± 0.15 kg, respectively) than the control group (0 day, 5.0 ± 0.00 kg). In addition, final BW significantly decreased in heat stress groups (3 days and 6 days, 211.8 ± 4.75 kg and 215.5 ± 3.50 kg, respectively) than the control group (0 day, 240.0 ± 25.00 kg). However, heat stress has no significant effect on blood parameter, serum T3 and cortisol. Nevertheless, heat stress increased HSPs mRNA expression in liver tissue, and serum concentration of HSPs. Despite Hanwoo cattle may have high adaptive ability to heat stress, our results suggested that heat stress directly effect on body temperature and respiration rate as well as serum and tissue HSPs. Therefore, we are recommended that HSPs could be the most appropriate indicators of Hanwoo cattle response to heat stress.

본 연구는 한우가격에 미치는 도체형질의 기여도 변화추세에 대해 조사하기 위해 실시하였다. 연구에 이용된 재료는 한우 거세우 35,247두의 도축자료를 이용하여, 자료의 구조분석과 일반성적, 분산분석 및 유의성검정, 가격에 대한 도체형질의 기여도분석을 실시하였다. 효과검정을 위해 등지방두께, 배최 장근단면적, 도체중, 근내지방도, 경락가격, 전체가격 등 6개의 형질을 이용하였고, 분석한 도축년도의 효과검정에서 조사된 모든 형질이 고도의 유의적인 차이(p<0.01)를 나타내었다. 한우가격에 미치는 도 체형질의 기여도 분석을 위해 다중회귀분석을 실시하여 각 독립변수의 준부분상관자승값(squared semi-partial correlation)을 이용하였다. 경락가격의 R2 값(결정계수)은 0.5422로 나타났고 전체가격 의 R2 값은 0.7141로 나타났다. 경락가격에 대한 준부분상관자승값 결과는 등지방두께가 0.0235, 배최 장근단면적이 0.0072, 도체중이 0.0001, 근내지방도가 0.3821로 나타났고, 전체가격에 대한 준부분상 관자승값은 등지방두께가 0.0161, 배최장근단면적이 0.0047, 도체중이 0.1691, 근내지방도가 0.2341로 나타났다. 가격에 미치는 도체형질의 기여도 변화추세는 2011년 이후 육질의 기여도가 꾸준하게 떨어지 는 추세를 보이고 있었고, 육량형질의 기여도는 높아지는 추세를 나타내고 있었다. 근내지방도의 가격 기여도가 낮아지는 것은 가격의 변화, 1등급 이상 출현율 상승, 도축물량증가로 인해 변별력이 떨어진 이유라고 보여지며 이러한 결과는 장기적인 관점을 가지고 지켜볼 필요가 있으며, 한우 산업이 경쟁력 을 갖기 위해서는 추가적인 연구가 진행되어야 할 것으로 사료된다.

본 연구는 한우의 전장유전체 내에 존재하는 단일염기 다형성(SNP)에 대해 DNA chip 분석을 통해 각 개체의 유 전자형을 파악하고, SNP 표지인자간 연관불평형의 크기를 알아보기 위해 실시하였다. 강원도에서 사육되고 있던 한 우 거세우 139두의 조직을 채취하여 DNA를 추출하였으 며, Bovine SNP50K BeadChip 분석을 이용하여 분석에 사 용 가능한 최종 35,769개의 SNP 표지인자를 얻어 연관성 분석을 실시하였다. 분석에 이용된 SNP 표지인자의 총 길 이는 2499.26Mb이었고, 전장 유전체에서 평균 대립유전자 빈도(MAF)는 0.273이었으며, SNP 표지인자간의 평균 거 리는 0.060과 0.082 사이에 분포하였다. 강원지역 내 한우 거세우를 이용하여 확인한 본 실험 결과는 기존의 전국의 한우를 대상으로 한 연구결과와 유사한 패턴을 보였다. 50Kb 이하로 인접한 거리를 갖는 SNP 표지인자들의 연관 불평형 값(r2)이 0.2 초과인 인자가 34%로 나타났다. 또한 SNP 표지인자간 거리가 멀수록 측정값이 떨어지는 지수형 식의 그래프를 보였다. 염색체별로 구분한 40kb 이하로 인 접한 SNP표지인자의 연관불평형 값(r2)은 0.2 이하로 나타 난 것이 총 7개(13, 15, 19, 23, 25, 28, 29번 염색체)였다. 종 합하여 볼 때, 본 연구 결과는 강원한우의 유전적 개량을 이 용한 기초자료로서 활용될 수 있을 것이며, 유전적 개량을 이용한 육종시스템에 도움을 줄 수 있을 것으로 기대된다.

본 연구는 산국 생균제가 비육후기 거세한우의 성장율과 육질에 미치는 효과를 조사하기 실시하였다. 거세한우 15두(565±17kg)를 시험구별 개시체중이 유사하도록 산국 생균제 무첨가구(CON), 농후사료의 0.2% 첨가구(LCB) 및 0.4% 첨가구(HCB)에 각 5두씩을 배치하고 150일간 사양시험을 실시하였다. 농후사료와 조사료를 8:2의 비율로 설정하고 생체중의 약 2.5%를 오전(8시)과 오후(5시)로 나누어 급여하였다. 미네랄 블록과 음수는 자유로이 섭취할 수 있도록 하였다. 사양시험 종료 후에는 모든 공시동물은 도축하여 도체특성을 조사하고 등심육을 채취하여 육질분석에 이용하였다. 개시체중과 종료체중은 처리구간 차이가 없었으나, 일당증체량, 사료섭취량 및 사료효율은 산국 생균제를 급여한 모든 시험구에서 대조구에 비해 개선되었다(p<0.05). 분 중 황화수소와 암모니아 가스는 시험구간 차이가 없었다. 신선육 관능평가에서 등심육의 육색은 산국 생균제를 급여한 시험구가 개선되었으나(p<0.05), 등심육의 물리화학적 특성과 기타 신선육 관능평가는 시험구간 차이가 없었다. 등심육의 지방산 조성은 산국 생균제를 급여한 시험구에서 C14:0과 C18:0 함량이 증가하였으며(p<0.05), HCB 시험구에서 C18:2n-6와 polyunsaturated fatty acid 함량은 HCB 시험구에서 가장 높게 나타났다(p<0.05). 따라서 비육후기 거세한우에 산국 생균제를 0.4% 수준으로 급여하는 것은 사료효율 개선, 육색 및 등심육 지방산 품질개선에 유리할 것으로 사료된다.

The objective of this study was to investigate meat quality and nutritional composition of 10 cuts (loin, striploin, chuck roll, chuck tender, short plate, brisket, bottom round, top sirloin, eye of round, and top round) from quality grade 1 beef from 11 Hanwoo steers at Hanwoo Experimental Station of National Institute of Animal Science. The protein contents were higher in top round (Udoon) and eye of round (Hongduke) and lower in loin (Dngsim) and short plate (Abjin) when compared to the other cuts (p<0.05). Whereas the intramuscular fat contents were highest in loin (12.51%), those were lowest in top round (4.14%) (p<0.05). The calories were higher in loin and short plate and lower in top round, chuck tender (Guri), top sirloin (Bosup), eye of round, chuck roll (Moksim), and bottom round (Sulgit) (p<0.05). The cooking loss (%) was 24.38% in loin and it was lower than the other cuts (p<0.05). The bottom round had higher water holding capacity (WHC) and chuck tender had lower WHC than those in the other cuts (p<0.05). In meat color, L* values were higher in loin and lower in top round than the other cuts (p<0.05). Total saturated fatty acid contents were higher in loin and lower in bottom round than the other cuts (p<0.05). In amino acid compositions, top round had significantly higher than those in the other cuts (p<0.05). The iron contents were higher in chuck tender and chuck roll contained higher iron contents than those of the other cuts (p<0.05). In conclusion, the meat quality and nutritional properties were significantly different among 10 cuts in the same quality grade of Hanwoo beef. Therefore, the provision of the meat quality and nutritional information of 10 cuts to consumers could be important for utilization and balanced consumption of different cuts.

본 연구는 부산물 혼합 silage 사료 급여가 한우 비육전기 거세우의 채식 및 반추행동에 미치는 영향을 규명하기 위하여 실시하였다. 시험에 사용한 공시한우는 21개월령 총 12두를 3처리로 배치하였으며, 이 때 처리구는 관행구 (C구: 농후사료+ 볏짚 자유채식)와 부산물 혼합 silage 구를 2처리 (T1: 농후사료+부산물 혼합 silage 제한급여 (1 kg) + 볏짚 자유채식, T2: 농후사료+부산물 혼합 silage 자유채식)로 하여 48시간

This study was to invesigate the effect of dietary supplemention of Pozzolan, Chromium-methionine chelate and rhus verniciflua stokes additive feed on growth performance and ultrasound live body characteristics in finishing Hanwoo steer. The animal used in the experiment were a total of 17 heads and weighted 577.09±35.90㎏. The experimental diets were basal hi-lok branded only concentrat and rice straw and 4% Rhus, 0.4% Cramin and 2% Pozzolan, which additice in basal diet. Individually average daily gain was tended to decreased with treated group. Ultrasound back fat thickness and marbling score were not significantly different(p<0.05)between teratment, however Pozzolan additive treat was showed tend to increased. Longissimus muscle area was showed tended to decreased in the Pozzolan treatment.

The present study hypothesized that ratio between carcass traits components could be applied for the understanding of yield index in Hanwoo steer. A thousand data was generated based on average carcass weight (CW), loin area (LA) and backfat thickness (BT) of Hanwoo steer in December 2018 for analysis 1. Then yield index (YI) was calculated using newly established yield index equation. The correlation between yield index and each carcass traits was visualized. In the interaction between carcass traits components (LA, CW, BT) and YI, only the interactions including BT showed a regular pattern to YI. Then changes of YI according to ratio of carcass traits components were investigated. The observed interactions between LABT and CWBT were similar with Monod equation model. The changes of YI to LABT and CWBT were fitted to Monod equation, and yield constants (K1 for LABT; K2, CWBT) of each equation were calculated as 0.47 and 2.20, respectively. Carcass traits from 5 commercial Hanwoo steer farm were then employed in the second analysis. Yield constants of each farm were estimated. In estimation, R2 value for K1 (LABT) showed greater than the K2 (CWBT). Finally, each farm was plotted based on their K1 and K2 values and it was found that greater yield index of Hanwoo steer was found as increased K1 and K2. As conclusion, the present study suggested the possibility of K1 and K2 values for understanding of yield grade equation and their application in the evaluation of new model for yield grade estimation and feeding strategy.

In this study, the effect of probiotic supplementation on growth performance, blood metabolites, and meat quality of Hanwoo steer was investigated. A total of 32 Hanwoo steers (15-17 months, average body weight 462±37.9 kg) were randomly allotted to 4 dietary treatments (0, 0.5, 1.0, and 1.5% mixed probiotics), with four Hanwoo steers per pen (two replicates per treatments), and reared for 12 months. There were no differences among treatments in growth performance of Hanwoo steer (P>0.05); however, feed intake decreased linearly with increasing levels of mixed probiotics. Growth hormone and Blood Urea Nitrogen (BUN) levels responded linearly with increasing levels of dietary mixed probiotics (P<0.05), but not insulin and blood glucose did not. In particular, total cholesterol was significantly lower for the 1% mixed probiotic treatment in comparison with that of the other treatments (P<0.05). The pH, Thiobarbituric Acid Reactive Substances (TBARS), cooking loss, and meat color were influenced by increasing levels of mixed probiotics (P<0.05), but the carcass characteristics and shear force were not. Regarding sensory evaluation, the addition of mixed probiotics resulted in significant difference in meat color, tenderness, aroma, off-flavor, juiciness, and marbling score, but not in overall acceptability. In addition, fatty acid profiles indicated no differences between control and mixed probiotic treatments. In conclusion, mixed probiotic treatment at 1% levels can enhance consumer preferences possibly by reducing cholesterol and TBARS.

This study was conducted to compare among bull, steer and heifer on growth performance, blood composition and carcass traits according to fattening phase in Hanwoo. 12 month of aged 4 bulls (339.8±18.5 kg), 4 steers (309.8±13.2 kg), and 3 heifers (290.0±16.7 kg) were allocated in the stalls with individual feeding system during 20 months. Average daily gain was not different among the treatment groups during early fattening phase, but higher in the bulls and lower in the heifers after mid-fattening phase (p<0.05). The difference of body size by animal groups appeared from 24 month of age, and wither height and body length of Hanwoo heifer were the smallest (p<0.05) among treatment group. But wither height was not difference among treatment groups at 32 month of age. At 12 month of age, concentrations of serum cholesterol, triglyceride, glucose and total protein were higher in the heifers compared to other groups, and serum GPT (Glutamic pyruvic transaminase) was the highest (p<0.05) in the bulls, and serum GOT (Glutamic oxaloacetic transaminase) was the highest (p<0.05) at late fattening phase in the bulls. Meat yield index was similar between the bulls and the heifers, and the lowest (p<0.05) in the steers. Marbling score was significantly higher (p<0.05) in the steers and the heifers than in the bulls, and meat quality was the best in the steers among treatment groups. The results of this experiment might be used as a basal data on difference between gender in revision of Korean feeding standard for Hanwoo.