Global research landscape and transfer-oriented synthesis of diet-based enteric methane mitigation in ruminants...

Enteric methane (CH₄) emissions from ruminants are a major contributor to agricultural greenhouse gases and represent both an environmental concern and an energy loss for the animal. Despite extensive research on dietary mitigation strategies, translating experimental findings into scalable, context-specific applications remains challenging. This study aimed to map the global research landscape on diet-based enteric methane mitigation and to develop an implementation-oriented framework that links intervention efficacy to transferability across diverse production systems.

A combined bibliometric and structured literature review approach was employed. A Scopus-indexed dataset (2005-2025) comprising 3,070 English-language documents from 456 sources was analyzed using the Bibliometrix package in R to evaluate publication trends, authorship patterns, country contributions, and collaboration networks. Concurrently, a structured narrative synthesis was conducted to classify dietary mitigation strategies into an implementation-relevant taxonomy and to identify constraints influencing cross-country transferability, including feeding systems, delivery mechanisms, and regulatory readiness.

The field exhibited rapid growth (18.38% annual growth rate), with nearly half of the publications produced since 2021. Research output involved 7,720 authors across 93 countries, reflecting strong collaboration (12.1 authors per paper; 37.72% international co-authorship) but significant concentration of influence among leading countries. The intervention landscape was organized into two principal categories: basal diet manipulation and feed additives/rumen modifiers. While numerous strategies demonstrated mitigation potential, their scalability depended largely on system compatibility, dose assurance, measurement, reporting, and verification (MRV) capacity, and regulatory frameworks rather than biological efficacy alone. Grazing-dominant and smallholder systems faced greater transfer constraints compared to confined feeding systems.

Diet-based methane mitigation research has evolved into a rapidly expanding, collaborative field; however, practical implementation remains limited by system-specific and institutional factors. Effective mitigation at scale requires context-adapted intervention portfolios aligned with local feeding systems, infrastructure, and regulatory environments. Integrating bibliometric insights with a transferability-focused framework provides a robust basis for prioritizing research and guiding policy and industry adoption without compromising ruminant productivity.