ABSTRACT
Methane emissions by livestock facilitate enteric microbial function, but result in a loss of feed energy to the animal. Measurements of emissions, particularly from ruminants, over the last century by animal nutritionists have sought to characterize and lead to methods to minimize methane emissions. Data describing these emissions have taken on a new importance since the recognition of the significance of methane as a greenhouse gas (Figure 1) and its role in atmospheric chemistry, including likely effects on ozone concentrations (Wuebbles and Tamaresis, 1993).
