Abstract

Methane is the main greenhouse-gas produced by New Zealand agriculture (Ministry for the Environment 2011). The methane loss from ruminants generally ranges from 4.5% to 9% of gross energy intake (Hammond et al. 2009). This indicates there is scope for lowering methane production. Replacing pasture forage with maize silage could decrease methane emission by altering fermentation patterns and by reducing rumen pH or ruminal retention time with the addition of starch to the diet (Beauchemin et al. 2008). However, Waugh et al. (2005) found that methane yield (g/kg DM intake) increased when pasture forage was substituted with up to 35% maize silage in dairy cows fed at similar intakes. Other literature suggests that methane yield in cattle responds in a quadratic manner when pasture forage is substituted with maize silage or grain (Blaxter & Wainman 1964; Arndt et al. 2010; Hassanat et al. 2012). This effect is associated with pasture forage quality (Kirkpatrick et al. 1997).

A, Jonker, and D Pacheco

Proceedings of the New Zealand Society of Animal Production, Volume 73, Hamilton, 202-204, 2013