The study aimed to investigate the impact of varying levels of neutral detergent-soluble fiber (NDSF) in Hanwoo growing cattle diets on rumen fermentation and methane (CH4) emissions. An in vitro rumen fermentation experiment utilized feeds with different NDSF levels, incorporating ingredients such as corn grain, soybean meal, soybean hulls, palm kernel meal, beet pulp and timothy hay. The NDSF contents in the diets were 9.02% (T1), 10.09% (T2), 12.42% (T3) and 14.63% (T4). In vitro dry matter digestibility (IVDMD) at 48 h was 7.4% higher for T4 compared to T1 (p<0.05). Total gas production at 48 h was 6.6% higher for T4 than T1 (p<0.05). CH4 production significantly decreased at 9 h and 12 h for T1 and T2 (p<0.05). At 48 h, CH4 production was 5.6% higher for T4 compared to T1 and 6.7% higher compared to T2 (p<0.05). At 12 h ans 24 h, the ammonia nitrogen concentration of T4 was approximately 33.1% and 40.4% lower, respectively, compared to T1 (p<0.05). The acetate to propionate ratio at 48 h was approximately 18.8% higher for T4 than T1 (p<0.05). From 9 h to 48 h, the proportions of butyrate and valerate were significantly higher for T4 (p<0.05). At 48 h, the dominant phylum in T4's rumen microbial community was Candidatus Thermoplasmatota Methanomassiliicoccus, an Archaea. Therefore, this study confirmed that increasing the NDSF content in growing Hanwoo cattle diets up to 12.42% increases IVDMD without increasing CH4 emissions, which is expected to positively impact Hanwoo productivity.

Ⅰ. 서론
Ⅱ. 재료 및 방법
    1. 공시 동물의 반추위 내용물 채취
    2. 실험사료 및 in vitro 반추위 배양실험
    3. 시료의 채취 및 분석 방법
Ⅲ. 결과 및 고찰
Ⅳ. 요약
Ⅴ. 참고문헌

• 정수연(한경국립대학교 동물생명융합학부 대학원생) | Soo Yeon Jung (Graduate student, School of Animal Life Convergence Science, Hankyong National University, Anseong 17579, Korea)
• 배귀석(한경국립대학교 바이오가스연구센터 전임연구교수) | Gui Seck Bae (Research professor, Biogas Research Center, Hankyong National University, Anseong 17579, Korea)
• 김상윤(한경국립대학교 동물생명융합학부 대학원생) | Sang Yoon Kim (Graduate student, School of Animal Life Convergence Science, Hankyong National University, Anseong 17579, Korea)
• Narantuya Batburged(한경국립대학교 동물생명융합학부 대학원생)
• 이혜안(한경국립대학교 동물생명융합학부 대학원생) | Hye An Lee (Graduate student, School of Animal Life Convergence Science, Hankyong National University, Anseong 17579, Korea)
• 강인기(한경국립대학교 동물생명융합학부 대학원생) | In Ki Kang (Graduate student, School of Animal Life Convergence Science, Hankyong National University, Anseong 17579, Korea)
• 최다현(한경국립대학교 동물생명융합학부 대학원생) | Da Hyun Choi (Graduate student, School of Animal Life Convergence Science, Hankyong National University, Anseong 17579, Korea)
• 김창현(한경국립대학교 동물생명융합학부 교수) | Chang Hyun Kim (Professor, School of Animal Life Convergence Science, Hankyong National University, Anseong 17579, Korea) Corresponding author