Moo-vement in the Field: Strategies for Reducing Methane Emissions from Cattle

Key Takeaways: 

• Cattle and other ruminant livestock are significant sources of methane, a potent greenhouse gas; making them a high-impact target for short-term climate mitigation.
• Reducing cattle-based methane emissions can be achieved through animal feed modification, improved manure management, and silvopasture practices.
• The Global Methane Pledge is a key component of the broader strategy for agricultural methane reduction, creating an international force committed to a 30% reduction in global methane emissions by 2030.

When thinking about tackling greenhouse gases, look to your dinner plate. Cattle, pigs, chickens, and other livestock are all sources of methane, a greenhouse gas 80 times more potent than carbon dioxide over a 20-year period and 27–30 times more potent over 100 years.

Cattle in particular produce significant amounts of methane because they are ruminant animals. The stomachs of ruminant animals contain a compartment called the rumen, which ferments partially-digested food to make it digestible. This fermentation produces enteric methane, which cattle emit when they burp.

Agriculture accounts for 40% of all manmade methane emissions, most of which are attributed to livestock. And according to the Environmental Protection Agency’s 1990-2023 Inventory of U.S. Greenhouse Gas Emissions and Sinks report, cattle produced 96% of all enteric fermentation methane in the United States in 2023. Globally, enteric methane from livestock accounts for about 60% of agricultural methane emissions and 25% of all human-caused methane emissions. In terms of the greatest single sources of methane emissions, livestock are second only to natural gas and petroleum systems (see the graphic below).

U.S. Methane Emissions by Source. Credit: U.S. EPA. Note: LULUCF stands for "Land Use, Land-Use Change, and Forestry."

These emissions have real, felt consequences for the United States. Although methane’s atmospheric lifespan is shorter than carbon dioxide's (7 to 12 years versus hundreds of years), its greater warming potential leads to more immediate environmental repercussions. As a major greenhouse gas, methane fuels increasing global temperatures, more intense extreme weather, and more frequent droughts worldwide. Methane can also trigger the formation of tropospheric ozone (a major component of smog), which can cause or worsen health conditions such as asthma, bronchitis, and emphysema. However, methane’s shorter life span and greater potency offer opportunities to slow the rate of climate change in the short term if its emissions are reduced. 

 

U.S. Action on Methane

Before the passage of the One Big Beautiful Bill Act (OBBBA) (P.L.119-21), the United States provided $1.36 billion in grants to reduce domestic methane emissions from the oil and gas sector through monitoring, detection, measurement, and quantification activities eligible under the Methane Emissions Reduction Program (MERP). After the OBBA’s passage, some of MERP’s funding was limited or repealed. In the absence of U.S. leadership, other countries have stepped up. The European Union, for example, announced plans to reduce its methane emissions in the energy sector.

Reducing Methane Through Cattle Diet Alterations

Methane emissions from cattle can be tackled by going straight to the source—altering cattle diets with feed additives that inhibit methane or modify rumen fermentation. Methane inhibitors, like 3-nitrooxypropanol (3-NOP) and bromoform (found in red seaweed), reduce methane by changing the chemical structure of the key drivers of methane formation during the cattle digestion process. Seaweed is the most effective methane inhibitor, reducing emissions by more than 90 percent, followed by fatty acids and 3-NOP. Rumen fermentation modifiers, like ionophores, tannins, and essential oils, cause changes in the rumen environment, which improve the productivity, health, and digestive efficiency of the animal. 

While bromoform-rich red seaweed is more effective in reducing emissions than 3-NOP, 3-NOP is more widely tested and approved, having received official approval in more than 65 countries. But the cost of adding 3-NOP to cattle feed is about $100–150 per animal per year, hindering large-scale use. Financial support mechanisms can help balance these costs. For example, several farms in the United States are using carbon credit programs to adopt 3-NOP. These farms track and report the emission reductions they achieve through 3-NOP use, creating carbon credits that are purchased by companies that need to offset their own emissions. 

Red seaweed is being further explored as a possible feed additive, but synthetic bromoform has proved to be more effective, and will likely be more affordable. Red seaweed additive costs an annual $300–500 per animal, which is significantly more expensive than 3-NOP and very likely more costly than synthetic bromoform. However, synthetic bromoform use poses several challenges, including health risks if cattle are misdosed, harm to the ozone layer if the compound is released, and health risks to the people handling the compound. If used carefully, however, bromoform provides a compelling opportunity for methane reduction. Bromoform has not yet been widely approved for use in its natural or synthetic state, though trials are underway. One such trial—the longest and largest for seaweed additives for dairy cattle to date—found that seaweed reduced enteric methane emissions by an average of 52% and up to 90%. After this successful trial, the California Department of Food and Agriculture authorized the commercial use of a seaweed-based supplement, Brominata, as a cattle feed additive in 2022. 

 

Reducing Methane through Manure Management

Although the majority of livestock methane emissions come from enteric fermentation, or cattle burps, 9.2% come from livestock manure. If left alone to decompose in place, manure releases high levels of methane into the atmosphere. These emissions may be reduced or even eliminated through anaerobic digestion, daily spread, or pasture-based management.

 

Anaerobic Digesters 

Anaerobic digesters use microorganisms to break down manure and other organic materials in a zero-oxygen container, capture and optimize methane released from manure breakdown by producing biogas. The process also creates digestate, which can be used (if properly treated) as animal bedding or fertilizer. On the other hand, anaerobic digesters require regular maintenance and management, have high upfront costs, and the process involves strict permitting requirements. 

 

Daily Spread

Daily spread involves spreading manure across cropland on a daily basis. Manure contains methane-producing microbes that thrive in low-oxygen environments. Spreading the manure outside in an oxygen-rich environment (as opposed to letting it pile up in a barn) renders the microbes inactive, facilitating low methane-emission decomposition. Daily spread is best suited for smaller farms in warmer climates, where manure can be distributed all year round. 

Inputs and outputs of anaerobic digestion process. Source: U.S. EPA

Pasture-Based Management

Pasture-based management keeps cattle in fenced pastures, rotating them consistently between different grazing areas to spread their manure evenly. This practice is also very effective at reducing manure-based methane emissions, but it works best in areas where the cattle can be kept outside year-round with adequate feed. Limitations include inclement weather, increased labor and planning, and difficulties in protecting the quality of water bodies in grazing areas. 

 

EESI Resources on Methane Emissions

For more information on methane emissions, check out these EESI resources: Article: Addressing Methane Emissions Is Critical for Fighting Climate Crisis Article: Out-of-This-World Methane Detection: Using Satellites to Track Super Emitters

Mitigation through Silvopastoral Systems

Silvopasture refers to the practice of grazing livestock alongside trees. It has been used around the world for millennia, and provides benefits such as carbon dioxide sequestration, increased biodiversity, improved soil health, erosion mitigation, and a wider variety of food for livestock. 

In addition to its environmental benefits, silvopasture offers a slew of economic benefits, including diversified economic opportunities in both the agricultural and timber markets and increased shelter and protection for livestock (shade from the trees reduces livestock heat stress while also improving pasture quality). Farmers also benefit from greater economic security, since the livestock provide a short-term revenue stream while timber provides a longer-term revenue source. This makes silvopasture a good opportunity for small-scale farmers.

 

Cattle-Produced Methane Reduction on the Global Stage

At the 2021 United Nations climate summit (COP26), President Biden and European Commission President Ursula von der Leyen introduced the Global Methane Pledge, which called on countries to take voluntary actions to reduce global methane emissions by at least 30% from 2020 levels by 2030. Methane emissions were also a focal point of the 2025 UN climate summit (COP30) in Belém, Brazil. As Brazil is the third-largest cattle producer in the world, agricultural methane emissions are a high-priority topic for the COP30 Presidency. Outside of official negotiations on the Global Methane Pledge at COP30, non-party organizations also held methane-related presentations, including one about the path to lowering livestock emissions. The Global Methane Pledge now has 159 participating countries, plus the European Commission.

Author: Olivia Benedict