Comparison of sulfur hexafluoride tracer technique, rumen simulation technique and in vitro gas production techniques for methane production from ruminant feeds

Studies carried out to compare sulfur hexafluoride tracer technique (SF6), rumen simulation technique (RUSITEC) with in vitro gas production technique (IVGPT) for estimation of methane (CH4) production from ruminant feeds. Five diets viz., alfalfa hay (D1), corn silage and soybean meal (SBM) (91:9, D2), Italian ryegrass hay and SBM (92:8, D3), rice straw and SBM (91:9, D4) and Sudan grass hay and SBM (92:8, D5) were evaluated for methane output by all the three techniques. RUSITEC has underestimated the methane output from all the diets compared with that of SF6, whereas the methane output estimated by IVGPT was very close to that of SF6. Therefore IVGPT seems to be a suitable tool for establishing a database on the methanogenic potential of ruminant diets.