Carbon farming: reducing methane emissions from cattle using feed additives

Feed additives or supplements offer one approach to reduce methane emissions from ruminant livestock. Livestock produce significant amounts of methane as part of their normal digestive processes. Some feed additives can inhibit the microorganisms that produce methane in the rumen and subsequently reduce methane emissions.

Why we should reduce livestock emissions

In Australia, direct livestock emissions account for about 70% of greenhouse gas emissions by the agricultural sector and 11% of total national greenhouse gas emissions. This makes Australia’s livestock the third largest source of greenhouse gas emissions after the energy and transport sectors. Livestock are the dominant source of methane (CH4) and nitrous oxide (N2O), accounting for 56% and 73%, respectively, of Australia’s emissions.

How methane is produced by ruminants

Ruminant livestock – cattle, sheep, buffalo, goats, deer and camels – have a fore-stomach (or rumen) containing microbes called methanogens, which are capable of digesting coarse plant material and which produce methane as a by-product of digestion (enteric fermentation): this methane is released to the atmosphere by the animal belching.

The amount of methane emitted by livestock is primarily driven by the number of animals, the type of digestive system they have and the type and amount of feed consumed. Ruminants are the principal source of livestock methane emissions because they produce the most methane per unit of feed consumed.