Methane production is given (A) per unit of dry matter intake (DMI), (B) as a proportion of gross energy intake (GEI) and (C) per unit of
digestible fibre intake (dNDFi)(at 75 % MER and when fed ad libitum) in comparison to ruminants (dark regression line; Franz et al., 2010) and non-ruminant mammalian herbivores (light regression line; Franz et al., 2011b).