Feed Additives to Reduce Enteric Fermentation Methane Emissions

Since the start of 2021, the demand for voluntary carbon offsets has increased dramatically with signs of more growth ahead. Supply will need to keep up with demand, which will likely require new carbon offset sectors to be developed. A promising sector to watch is the use of cattle feed additives to reduce methane emissions from enteric fermentation. Enteric fermentation occurs during digestion in ruminant animals. Methane emissions in the United States are estimated at 216 MMTCO2e per year, of which 67% can be attributed to enteric fermentation. Reducing these emissions could be crucial to lowering agriculture’s greenhouse gas impact.

Feed additives can inhibit microorganisms that produce methane in the rumen of cattle. The additives can be natural feed supplements like garlic, or plants like kelp. A few controlled studies have been conducted to determine the reductions associated with feed additives. Sunflower or canola oils can reduce methane emissions by 9-27%. But studies have shown seaweed can reduce methane enteric fermentation emissions by 90%. Beyond reducing methane emissions, seaweed farming increases carbon sequestration in oceans and reduces ocean acidification.

The Gold Standard and VERRA both have approved methodologies for the use of feed additives. So far, there has been low adoption of this technique in the United States. The California Air Resource Board’s Carbon Offset Task Force identified the use of feed additives as a potential sector for the compliance market in future years. They note studies need to be replicated and most feed additives need to be FDA approved. Currently the use of feed additives in the market has not shown to be economically beneficial for dairy or beef operations. Carbon offset funding could provide the economic incentive for adoption of the practice. Overall, the evolution of this sector should be closely watched as a viable way to support dairy and cattle operations while providing significant atmospheric benefit.

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