The present experiment was designed to investigate the effects of extruded linseed supplementation on methane production in Holstein steers. Four Holstein steers fitted with permanent cannulas were assigned to two dietary treatments in a duplicated 2 × 2 Latin square design: a control diet consisting of tall fescue straw (65%) and concentrate (35%), and a treatment diet supplemented with 3.8% extruded linseed by replacing a part of ingredients in the concentrate of the control diet. The concentrates of the control and the treatment diet were isoenergetic and isonitrogenous. Extruded linseed supplementation did not affect dry matter intake but significantly (P<0.05) increased the intake of lipid. Rumen pH was significantly (P<0.05) lower for control than for treatment. Although there was no significant difference between treatments, the concentration of total VFA in control was 21% higher than in treatment. The concentrations of acetic acid, propionic acid and butyric acid were not different between treatments. Extruded linseed supplementation significantly (P<0.05) reduced methane output(g/d) and emission factor. Methane conversion rate was lower for treatment than for control but no significant difference was found. The results of the present study showed that extruded linseed supplementation in the diet of Holstein steers could reduce methane output.

• 우양원(서울대학교 국제농업기술대학원) | Yang Won Woo (Graduate School of International Agricultural Technology, Seoul National University, Pyeongchang 25354, Korea.)
• 이창현(건국대학교 동물자원과학과) | Chang Hyun Lee (Department of Animal Science and Technology, Konkuk University, Seoul 05029, Republic of Korea.)
• BharanidharanRajaraman(서울대학교 그린바이오과학기술연구원) | Bharanidharan Rajaraman (Institute of Green Bio Science & Technology, Seoul National University, Pyeongchang 25354, Korea.)
• 여준모(국립한국농수산대학 대가축학과) | Joon Mo Yeo (Dept. of Beef & Dairy Science, Korea National College of Agriculture & Fisheries. Jeonju 57874, Korea.)
• 이원영(국립한국농수산대학 대가축학과) | Won Young Lee (Dept. of Beef & Dairy Science, Korea National College of Agriculture & Fisheries. Jeonju 57874, Korea.)
• 김도형(경북도립대학교 축산과) | Do Hyung Kim (Department of Animal Science, Gyeongbuk Provincial College, Yecheon 36830, Korea.)
• 장선식(국립축산과학원 한우연구소) | Jang Seon (Hanwoo Research institute, National Institute of Animal Science, Pyeongchang 25340, Korea.)
• 김경훈(서울대학교 국제농업기술대학원) | Kyoung Hoon Kim (Graduate School of International Agricultural Technology, Seoul National University, Pyeongchang 25354, Korea.) Corresponding author