FROM THE FARM REPORT: A 3D VIEW OF FEED ADDITIVES FOR ENTERIC METHANE MITIGATION

There have been increasing partnerships between different groups over the years to tackle the problem of greenhouse gas emissions (GHGs) from agricultural production and improve the environmental footprint of the agricultural sector. One of these coalitions is “The Global Research Alliance on Agricultural Greenhouse Gases” (GRA) launched in December 2009, with a current membership of 68 countries across the world including affiliates, with partners like the World bank, Consultative Group on International Agricultural Research (CGIAR), African Development Bank, European Commission, Food and Agriculture Organization (FAO), Global Methane Hub, World Farmers Organization (WFO), and other relevant organizations.

The GRA focuses on four broad research groups which are the Livestock, Paddy Rice, Croplands, and Integrative Research Groups, which helps to narrow down research efforts and scientific knowledge specific to reducing GHGs from the individual sub-sectors. The overall aim of the GRA is to combat climate change from an agricultural standpoint and increase agricultural production to meet the growing demand for quality food globally. As part of its arms, the GRA also has flagship projects which bring together experts in specific research areas pertinent to its collective goal. There are currently six flagship projects which are Agroecology & Agroforestry to Mitigate Climate Change, Economics of Cattle GHG Mitigation (EMiFa), Ensuring Long-Term Mitigation and Adaptation Co-Benefits, Feed Additives to Reduce Methane, RUMEN Gateway, Reducing N2O Emissions and Improving Accounting, and Satellite Monitoring to Improve Livestock Management.

The first output of the Feed Additives to Reduce Methane flagship project was published as a special issue in the Journal of Dairy Science in January 2025. This flagship project was developed by the Livestock Research Group and Feed and Nutrition Network, and it is titled Technical Guidelines to Develop Feed Additives to Reduce Enteric Methane. It brought together 60 leading researchers from 46 institutions across 23 countries. The special issue contains six articles that elaborately and wholistically discuss this subject. In introducing the articles, Dr Michael Kreuzer (professor emeritus at ETH Zurich, Lindau, Switzerland) said “The flagship's main goal is to accelerate the development and use of feed additives to assist in reducing global enteric methane emissions from ruminant livestock. Its purpose is also to provide the scientific community and livestock sector with technical guidelines on good practices for developing and testing feed additives.” The titles of the six articles are:

Feed additives for methane mitigation: A guideline to uncover the mode of action of antimethanogenic feed additives for ruminants.

Feed additives for methane mitigation: Assessment of feed additives as a strategy to mitigate enteric methane from ruminants—Accounting; How to quantify the mitigating potential of using antimethanogenic feed additives.

Feed additives for methane mitigation: Modeling the impact of feed additives on enteric methane emission of ruminants — Approaches and recommendations.

Feed additives for methane mitigation: Recommendations for identification and selection of bioactive compounds to develop antimethanogenic feed additives.

Feed additives for methane mitigation: Recommendations for testing enteric methane-mitigating feed additives in ruminant studies.

Feed additives for methane mitigation: Regulatory frameworks and scientific evidence requirements for the authorization of feed additives to mitigate ruminant methane emissions.

The authors highlighted the difference between the efficacy and effectiveness of antimethanogenic feed additives (AMFA). According to them, the former is based on results from controlled interventions while the latter relates to results from real-world conditions. Some key points and recommendations from the articles (in order of how they are listed above) are:

The effectiveness of an AMFA in in-vitro (laboratory) or in-vivo (live animal) studies should be confirmed, as well as its safety for animal production and health, before more resources are channeled to determine its mode of action.

Efficacy and effectiveness must be considered in accounting for the mitigation potential of an AMFA. A life cycle assessment is also important to determine the wholistic impact of an AMFA.

Models should be tailored to specific situations, for example, the outcome of adopting an AMFA would be different between a pasture system and an intensive system. Also, peer-reviewed sources are highly recommended as data sources for modeling.

In determining the right AMFA to adopt, it’s recommended to start with in-vitro systems that allow more products to be tested per time, and then the more promising ones (based on the in-vitro results) can be used in in-vivo testing.

Long-term studies are needed as we consider the effects of AMFA. When two or more AMFA are used in a study, the efficacy and mode of action of the individual AMFA should be determined. The gas measurement technique adopted should not adversely affect the normal behavior and productivity of the study animals. The constituents of an AMFA should be determined before animal studies to avoid any harmful impacts on the animals and humans.

The regulatory approval of AMFA is based on jurisdiction, but the major consideration across all jurisdictions is that the AMFA is effective in reducing enteric methane emissions without any detrimental effects, and this must be proven with scientific data. It is also recommended that farmers and other stakeholders should be informed of the pros, cons, as well as appropriate usage of approved AMFA.

As we continue to address the questions of efficacy, effectiveness, and sustainability of feed additives in rumen methane mitigation, these articles provide useful information for researchers, farmers, and the dairy industry at large to think through these issues more systematically.

— Gift Omoruyi

gomoruyi@whminer.com