| Abstract: | The current study is aimed at determining the effect of different grass silages on enteric methane production from dairy cows and to determine the effect of changing the forage/concentrate ratio on enteric methane production. In the current study, enteric methane was not measured from animals, rather it was estimated using existing equations from the literature. Rations were formulated using six grass forages as the core for the rations. An existing model (SAC FeedByte), which simulates the physical processes based on least cost diet formulation and linear programming modelling, was used to formulate the rations. Enteric methane (/cow/day) that would be produced had a cow been fed that ration was calculated using a set of two different equations. The proportion of concentrates relative to the silage had a significant (p < 0.001) effect on enteric methane production. The results showed that high-quality silage resulted in low enteric methane emissions/litre of milk. Also, a high proportion of concentrate in the ration resulted in low amount of enteric methane produced/kg of milk. Carbon footprinting of dairy production systems should, therefore, account for the variation in forage quality. |
