Non-Nutritive Feed Additives: Methane Inhibitors
alternative practice names:
3-NOP
Non-nutritive feed additives are included in the cow’s diet in very small quantities to reduce enteric methane production but not to provide nutrients. Methane inhibitors are a type of feed additive that directly inhibit rumen methanogenic archaea from making methane.
3-Nitroxypropanol (3-NOP/Bovaer®) is the only compound approved for enteric methane mitigation in the U.S. 3-NOP is a synthetic compound that specifically inhibits the enzyme methyl-coenzyme M reductase, which is essential for methane production in the rumen. By blocking this enzyme, 3-NOP reduces the formation of methane. 3-NOP is added to feed in small doses, making it relatively feasible to implement. However, the cost for producers remains a significant challenge.
Other methane inhibitors include halogenated compounds (e.g., chloroform and bromoform); seaweeds, including bromoform-containing species (e.g., Brominata); and nitrates. However, these compounds are not approved in the U.S. for the intended use of enteric methane mitigation.
When used, in what regions in the U.S. is the practice found:
Northwest, West, Upper Midwest, Southwest, Northeast, Southeast
FARM SIZE
When used, typically found on farms of the following sizes:
All Sizes

Practice Benefits
Limited impact on animal performance: Methane production is a normal part of microbial fermentation in the rumen, helping to remove excess hydrogen. Contrary to theories, there is no evidence that inhibiting methane improves animal performance; in fact, it tends to reduce feed intake and milk production. The challenge lies in finding doses that reduce methane without negatively impacting productivity. 3-NOP has been developed based on research to achieve methane mitigation in dairy cattle without reducing performance, but no evidence supports productivity improvements from methane inhibition at this time.

Implementation Insights
Site-specific or Farm-specific requirements

In most cases, there are no specific site or farm requirements.
Required Capital Expenditures (CapEx)

No capital expenses are required.
Required Operational Expenditures (OpEx)

Methane inhibitors: The cost of 3-NOP can be a significant expense for farmers. While financial incentives and carbon credits may help offset the cost, farmers often need to front the expense and wait for reimbursement or financial returns through carbon credit programs or government incentives.
Precision in application: The use of 3-NOP requires accurate dosing and precise application to ensure effective methane reduction without compromising animal performance. This demands ongoing monitoring and careful management to adjust dosages as needed, adding complexity to routine operations.
Implementation Considerations

Sourcing: 3-NOP is in high demand and available only in certain milksheds or regions where companies have negotiated access.
Navigating carbon markets: Farmers will need to navigate new carbon credit markets and incentive structures to justify their costs and secure funding to support use. Record keeping is crucial, as farms must accurately track methane inhibitor usage and other relevant data to ensure compliance with carbon credit systems and facilitate third-party verification of emissions reductions.
Dietary fiber: 3-NOP's effectiveness in reducing methane emissions is diminished in diets with higher dietary fiber (NDF) levels. Adjustments to the feed composition may be necessary to increase the effectiveness of methane mitigation.
Management and training: Successful implementation of methane inhibitors often requires additional training for farm staff to understand the benefits and proper usage of these products. This can add a layer of complexity to the operation, particularly in larger farms where multiple employees are involved in feed management.
Financial Considerations and Revenue Streams
PROFIT POTENTIAL
While the methane inhibitor itself has upfront costs, the financial impact is partially offset by potential returns from carbon credit markets and government incentives, with an estimated annual return of around $20 per lactating cow (Watson, 2024).
CARBON MARKETS
This practice is commonly credited in carbon markets. The practice can generate both offset and inset credits.
Notes:
Projects are required to have at least 2-3 years of herd records prior to the start of a project. Methane reductions are calculated using researched emissions factors or direct monitoring of methane emissions on site.
Producers need to integrate a new feed ingredient that has proven to result in reduced methane emissions. Eligible feed ingredients cannot already be commonly integrated into feed rations.
This practice is usually credited over 7-10 year creditting periods, but there is generally no risk of "reversing" emissions (see Verra and Gold Standard methodologies).
Depending on the efficacy of available methane inhibitors, the expected credit volume is typically between 0.92-1.48 tons per head per year (Kebreab et al., 2023).
Additional Resources
Evaluation Tool: Evaluation Tool for Enteric Methane Mitigation (Dairy Management Inc.)
Presentation: Feed Additive Evaluation Guidance for Enteric Methane Mitigation (Dairy Management Inc)

Environmental Impacts
REDUCES FARM GREENHOUSE GAS FOOTPRINT
Studies have demonstrated that 3-NOP can reduce methane emissions by up to 30% without adversely affecting animal health or productivity. It is considered one of the most effective and promising enteric methane inhibitors available.
REFerences

Alignment with FARM Program
FARM Environmental Stewardship (ES) V2-V3 Alignment
FARM ES Version 3 allows users to specify the use of certain methane-reducing feed additives: 3-NOP.
Contents
We're always eager to update the website with the latest research, implementation insights, financial case studies, and emerging practices. Use the link above to share your insights.
We're always eager to update the website with the latest research, implementation insights, financial case studies, and emerging practices. Use the link above to share your insights.
Non-nutritive feed additives are included in the cow’s diet in very small quantities to reduce enteric methane production but not to provide nutrients. Methane inhibitors are a type of feed additive that directly inhibit rumen methanogenic archaea from making methane.
3-Nitroxypropanol (3-NOP/Bovaer®) is the only compound approved for enteric methane mitigation in the U.S. 3-NOP is a synthetic compound that specifically inhibits the enzyme methyl-coenzyme M reductase, which is essential for methane production in the rumen. By blocking this enzyme, 3-NOP reduces the formation of methane. 3-NOP is added to feed in small doses, making it relatively feasible to implement. However, the cost for producers remains a significant challenge.
Other methane inhibitors include halogenated compounds (e.g., chloroform and bromoform); seaweeds, including bromoform-containing species (e.g., Brominata); and nitrates. However, these compounds are not approved in the U.S. for the intended use of enteric methane mitigation.
Practices and technologies
Non-Nutritive Feed Additives: Methane Inhibitors
alternative practice name:
3-NOP