Measurement of methane emissions from cattle using chambers and micrometeorological techniques

Agriculture in Canada contributes 8.3% of all greenhouse gas (GHG) emissions found within Canada. Methane (CH₄) emissions are a major source of these agriculture GHG emissions most of which are a result of enteric fermentation by cattle. Our study looked at three approaches to measuring enteric CH₄ emission. The first approach used four large flow-through steady-state chambers where each chamber housed two steers. These chambers proved sensitive enough to identify dietary additives that potentially reduce CH₄ emissions. For example, the use of sunflower oil was shown to reduce CH₄ emission of cattle on a high forage diet by 22% relative to the control. Overall, CH₄ emissions varied from 129 to 181 g steer^-1 d^-1. The second approach was to measure CH₄ emissions from two isolated pens of cattle using open-path lasers along the downwind perimeter and the integrated horizontal flux technique. The final approach was to measure CH₄ emissions from whole livestock facilities using a dispersion model technique. In all three studies, animal production data were collected to coincide with CH₄ emissions.