Role of Tannins in Reducing Methane Emissions from Ruminant Livestock: A Case Study

Abstract This study provides a practical description of secondary metabolites present in plants, with particular attention to the use of tannins in ruminant feed to reduce enteric methane (CH 4 ) production. It presents the mechanism of action of tannins in the ruminant organism upon ingestion and the pathways they may follow to reduce enteric CH 4 levels in ruminants. A study is presented that evaluates the in vitro diet inclusion of Tagetes erecta , given its high tannin content, and its effect on CH 4 production in ruminants. The in vitro study found that tannins can reduce CH 4 production by up to 39% with the addition of T. erecta . Therefore, tannins offer a viable resource for reducing CH 4 production in livestock systems. However, their application should be evaluated on a case-by-case basis, considering that their effectiveness depends not only on the dose incorporated into the diet but also on their influence on production parameters such as digestibility and feed intake. Information © The Authors 2026