Enteric methane emissions from dairy cows fed different proportions of highly digestible grass silage.

摘要

Enteric methane (CH₄) emissions were measured from six lactating dairy cows using the sulfur hexafluoride tracer technique. Three diets with different proportions of highly digestible grass silage/concentrates were fed: 500/500, 700/300, or 900/100 g kg-1 dry matter (DM). The average daily CH₄ emissions were 282, 300, and 321 g animal-1, respectively and the methane conversion factor (Y_m) from gross energy (GE) ranged from 0.051 to 0.056. However, the statistical power of the study was weak and the differences between diets were not significant (p=0.149 and p=0.293, respectively). A linear regression analysis showed a trend (p=0.08) toward higher enteric CH₄ emissions with higher proportion of high quality grass silage in the diet. A definite conclusion is not possible and further studies are needed as a base for concrete advice on how to mitigate enteric CH₄ emissions from high yielding dairy cows in Scandinavia.