Refining direct fed microbials (DFM) and silage inoculants for reduction of methane emissions from ruminants

This proposal is focused on implementing the use of lactic acid bacteria (LAB) as an approach to reduce methane emissions from ruminant livestock. The goal will be to refine current on-farm LAB technologies such as direct-fed microbial supplements and/or silage inoculants, currently used to increase production and improve health of animals, with a methane-reducing benefit. Selected METHLAB strains will be tested in ruminants (cows and sheep) to confirm efficacy of methane reductions in vivo. LAB offer a safe, practical and natural way to influence the rumen microbial community for methane mitigation, creating a more sustainable, emission-efficient food production system. LAB are natural inhabitants of the gastrointestinal tract of ruminants but are also well established as industrial micro-organisms, economically produced in large quantities for incorporation into feed products, making them ideally suited as a microbial technology. The partners in this proposal are from Global Research Alliance (GRA) member countries that share the goal of reducing methane emission intensity across ruminant classes in a manner that maintains agricultural production and sustains environmental integrity. METHLAB brings together a global network of multidisciplinary researchers to enhance impact and advance the knowledge transfer of LAB on-farm technologies to address the reduction of enteric methane emissions in ruminant (specifically cattle and sheep) production systems. Using superior microbial inoculants (which we will identify in the project), we aim to improve the quality of ruminant feeds which will lead to a reduction in methane and enhanced livestock production. METHLAB will thus lead to environmental and societal benefits with the potential to deliver green jobs and increase competitiveness in the agri-food sector.

Teagasc, Ireland
Prof. Catherine Stanton

Project partners
University College Cork, Ireland
Institut National de Recherche en Agronomie (INRA), France
Animal Nutrition Group, Wageningen University, The Netherlands
AgResearch Limited, New Zealand
SACCO S.R.L, Italy

Total requested funding
1,036,000 €

Project duration
36 months

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The MethLAB consortium met face to face on 17-18th of April 2019, in Chicago, when we discussed in detail the MethLAB project results and future planning with all partners. Following an intensive screening programme between the AgResearch (New Zealand) and Teagasc/UCC (Ireland) laboratories, excellent progress has been made on the identification of lactic acid bacteria (LAB) for use as silage inoculants for inhibition of methane production in ruminants. Some of these strains include cultures from our commercial Italian partner Sacco who are experts in the commercial production of lactic cultures for a variety of applications. In addition, a number of strains that showed potential as methane reducers were also found to display bacteriocin production at Teagasc/UCC. Some of the active LAB strains were tested as silage inoculants in vitro (INRAE, France and WUR, NL). This led to identification of strains that ranked best in terms of reduced loss in DM and digestibility and these were selected for animal feeding trials following silage production in The Netherlands, Ireland and New Zealand, in cattle and sheep during 2020. To date, the sheep feeding trials have already been conducted in New Zealand (completed mid-March, 2020) with data analysis yet to be completed, and there was no reduction in methane emissions attributable to the METHLAB-inoculated silage feeding in that trial. AgResearch laboratories were temporarily closed on the 24th March due to the Covid-19 Alert Level 4 restrictions in New Zealand. Now under Alert Level 3, analyses are being conducted on sheep rumen and faecal samples collected for microbial community profiles and metabolites and it is anticipated to be able to complete sample analysis by the 30th of June, followed by a draft manuscript on the sheep trial results. In The Netherlands, researchers at WUR prepared silage inoculated with selected LAB for the in vivo total Carbon and Nitrogen balance trial, which is currently running with eight dairy cows in a replicated Latin square design in climate-controlled respiration chambers and will be completed in June 2020. Chemical analyses will start as soon as Coronavirus lock-down restrictions are lifted. This had operational consequences for the lab that was fully closed for 1 month and is now working an estimated 30% of its capacity. It is hoped that after June 1st, some of these restrictions may be lifted. Silage production in Ireland using the METHLAB strains is due to start late May/ early June 2020 in Teagasc and the animal trial is planned to proceed in August 2020 using 30 Holstein dairy cows divided into two groups then fed the treatment and control silage. Analysis of rumen and faecal samples will be conducted along with the assessment of animal production and methane outputs.

Funding ends for AgResearch on 30/06/2020 and for European METHLAB partners on 31/10/2020. The final meeting was planned in Cork, Ireland in June 2020, but was cancelled due to the Coronavirus pandemic, and an online video link to conduct this meeting remotely will be held instead.


MethLAB partners from both New Zealand and Ireland contributed toward the publication of a critical literature review in Frontiers in Microbiology (October 2019): Doyle N, Mbandlwa P, Kelly WJ, Attwood G, Li Y, Ross RP, Stanton C, Leahy S. (2019). Use of Lactic Acid Bacteria to Reduce Methane Production in Ruminants, a Critical Review. Front Microbiol. 2019 Oct 1;10:2207. doi: 10.3389/fmicb.2019.02207. eCollection 2019. Review.PMID:31632365. This paper outlines the current literature, as well as a comprehensive analysis of the potential use and mechanisms of LAB as methane reduction strategies.

Stanton C, Leahy S, Kelly B, Ross RP, Attwood G. (2020). Manipulating the rumen microbiome to address challenges facing Australasian dairy farming. Animal Production Science,

AT WUR, part of the data involving the in vitro screening trial which identified the most promising LABs as silage inoculants was published at the Congress on gastrointestinal function, Chicago, USA, 15-17 April 2019. A manuscript is under preparation to be submitted in July for a special issue on "Potential Roles of Forage Silage in Sustainable Agricultural Production" in Agronomy, special editor Vincent Niderkorn (INRAE).

There have been invitations to contribute toward two book chapters which are due to be published in 2021: Both of these publications are led by Catherine Stanton and aim to highlight both the importance of reducing enteric methane emissions globally, and the method by which this may be achieved, namely through the introduction of bacteriocin producing cultures:

·         Bacteriocins: Novel applications in food, and human and animal health: Elsevier publishing.

·         The use of feed supplements to reduce livestock greenhouse gas emissions: direct-fed    microbials: Burleigh Dodds Science Publishing.

The consortium has also been involved in presenting the work of the MethLAB project at several conferences. These include; “International Conference on Agricultural GHG Emissions and Food Security Connecting Research to Policy and Practice”, Berlin, Germany (August 2018); “Australasian Dairy Science Symposium”, Palmerstown North, New Zealand (November, 2018); “Congress of Gastrointestinal Function”, Chicago, USA (April, 2019); and “Teagasc SRUC Conference, Rural Futures II”, Dublin, Ireland (January 2020).