Estimation of Methane Production in Ruminants

Abstract

The relationship between dry matter intake (DMI) and methane (CH4) production was investigated using results obtained from 190 energy balance trials with dairy cattle, beef cattle, sheep and goats to predict total methane emission from livestock in Japan. The results were as follows : 1) CH4 production per unit of feed intake decreased as feeding level increased although the absolute amount of CH4 production increased. 2) Therefore, the relationship between CH4 production (Y, l/day) and DMI (X, kg/day) can be expressed as a quadratic form. The equation best fitted to the data for all aminals was Y=-17.766+42.793X-0.849X2 (r=0.966). 3) From the estimation equation, average dry matter intake and cattle populations, annual CH4 production was estimated to be 0.182 teragrams (Tg) from dairy cattle and 0.150Tg from beef cattle. Total CH4 emission from ruminant livestock in Japan was estimated to be 0.332 Tg/year, and total CH4 emission from all livestock including ruminants, pigs and horses was 0.345 Tg/year in Japan. This only accounts for around 0.5% of total CH4 emissions from animals all over the world.