In vitro rumen methane output of forb species sampled in spring and summer

Abstract

The chemical composition, in vitro rumen fermentation variables and methane (CH4) output of a range of common forb species sampled in spring and summer, and grass silage (14 treatments in total), were determined in this study. Dried, milled herbage samples were incubated in an in vitro rumen batch culture with rumen microbial inoculum (rumen fluid) and buffered mineral solution (artificial saliva) at 39 °C for 24 hours. All herbage chemical composition and in vitro rumen fermentation variables were affected (p<0.001) by treatment. Rumex obtusifolius (in spring and summer), Urtica dioica (summer) and Senecio jacobaea (summer) had lower (p<0.05) CH4 outputs relative to feed dry matter incubated compared with grass silage, reflecting their lower extent of in vitro rumen fermentation.