Antimethanogenic Feed Additives

Antimethanogenic Additives

Over half of dairy emissions come from enteric methane.
Special feed additives suppress this gas, without affecting milk yield or animal health.

See impact

The Climate Issue

Cows produce methane as part of their natural digestion. When they eat, microbes in the rumen break down fibrous feed. One of the by-products is methane – expelled mostly through burping.

On pasture-based farms, this enteric methane makes up over 55 % of total greenhouse gas emissions. It doesn’t hurt the cow, but it’s a major climate issue. Methane is 28 times more powerful than CO₂ and acts quickly in the atmosphere.

Unlike other sources, enteric methane is hard to capture or offset. Without action in the diet, these emissions remain high even on efficient farms.

The Solution: Feed Additives

Feed additives offer a new way to tackle enteric methane at source. These natural or synthetic compounds work inside the rumen, where they inhibit methanogenic microbes or alter fermentation.

Additives like 3-NOP (Bovaer®), algal-based products (Algolin®), or essential oil blends (SilvAir®) can cut methane by 20–40 % without affecting milk production. They allow cows to digest more efficiently, keeping energy for growth rather than waste gases.

Even at small doses, these additives have strong effects. Trials show methane drops immediately, with no negative impact on health or fertility.

Talk to our team

Key Benefits when using Feed Additives

Cut Emissions

Additives directly inhibit methane production in the cow’s rumen, reducing one of the hardest-to-abate farm emissions by up to 40 %.

Feed Efficiency

By shifting how cows digest fibre, some additives improve feed conversion – meaning more milk from the same feed or less feed for the same yield.

No Yield Loss

Properly tested additives do not reduce milk output or solids. They can be safely included in meal or TMR, even under high-performance systems.

Impact of using Feed Additives

Feed additives are one of the most promising new mitigation tools for livestock systems. When combined with other strategies, they significantly reduce emissions without lowering productivity.

Studies across EU pasture systems show that methane-reducing feed additives can:

Cut enteric methane by 20–40 %
Lower total farm emissions by 10–15 %
Improve feed efficiency by 2–3 % in some cases
Support compliance with future climate rules

Below, we show the impact of adopting additives across three common dairy scenarios.

Scenario	Additive Cost per Cow	Net Cost / 100 Cows	GHG Emissions	% GHG Reduction
0% Implementation	-	-	0.960 kg CO₂-eq/kg milk	0% kg CO₂-eq/kg milk
50% Implementation	€75	€3,750	0.889 kg CO₂-eq/kg milk	7.4% kg CO₂-eq/kg milk
100% Implementation	€75	€7,500	0.820 kg CO₂-eq/kg milk	14.6% kg CO₂-eq/kg milk

Jump to research

Considerations

Additive Type & Supply

Additives like 3-NOP (Bovaer®), Algolin®, and SilvAir® are among the most trialled, but supply chains are still maturing. Cost, consistency, and ease of sourcing must be assessed before on-farm use.

Feeding System

Additives work best in Total Mixed Ration (TMR) or compound meal systems. In pasture-based systems, impact is lower due to variable intake, and daily feeding routines may need adjustment.

Regulations

Most additives require regulatory approval and declarations for traceability and carbon crediting. Always use certified products and keep records to meet EU or national compliance.

Implementation

Start small and scale up. With the right product and feeding plan, you can reduce methane significantly with no disruption to yields or animal health. Here’s how to begin.

Choose the right additive. Work with your nutritionist or supplier to select a methane-reducing additive tested for your herd type and system.
Update your ration. Incorporate the additive into your existing meal or TMR. Ensure cows get a consistent daily dose for maximum effect.
Monitor performance. Track milk yield, solids, and cow health to confirm no side effects. Adjust dosage based on results and supplier guidelines.

Behind the Research

ODOS Tech was founded by Cian White and Alejandro Vergara, two sustainability specialists with deep expertise in agricultural climate action.

Cian, a researcher at Trinity College Dublin with a background in environmental science, works on restoring nature to increase biodiversity on farms by using satellite images to track trees, hedgerows, and other habitats. Alejandro, a PhD researcher at University College Dublin, helps farmers measure their carbon emissions footprint and implement mitigation strategies to reduce their impact.

Together, they helped lead the carbon and nature-based work for the Farm Zero C project at Shinagh Farm, one of Europe’s first net-zero dairy pilots. At ODOS, they build smart, science-based tools to help agri-food businesses protect the environment and restore nature.

Research

Teagasc Feed Trials

Irish and EU trials show that feed additives like 3-NOP can cut methane by 30 % or more, even in pasture-based diets. Milk yield remains stable, with minor feed efficiency gains in some herds.

Farm Zero C Pilot

At Shinagh Farm, trials with enteric inhibitors showed immediate methane reductions. The additives were well tolerated and caused no drop in production across the study period.

IPCC Recommendations

The IPCC lists enteric methane inhibitors as a key strategy for climate-smart livestock. While still emerging, these tools are likely to play a central role in future farm compliance and emissions planning.