Sustainable Livestock Transformation in Low- and Middle-Income Countries: An Umbrella Review Protocol

Livestock systems in low- and middle-income countries (LMICs) are central to food security, nutrition, livelihoods, and environmental sustainability, yet the evidence base on their multiple roles remains fragmented across disciplines and outcome areas. This umbrella review protocol outlines a systematic evidence-mapping approach to identify and characterize existing review-level evidence on the relationship between livestock systems and four broad outcomes in LMICs: food security, nutrition, and healthy diets; livelihoods and inclusive economic growth; One Health; and sustainable natural resource use, climate action, and biodiversity. The review will draw on systematic reviews, meta-analyses, scoping reviews, systematic maps, and evidence and gap maps published from 2006 onwards in English, French, and Spanish. Searches will be conducted across major bibliographic databases, web-based search engines, organizational repositories, and review registries. Eligible evidence will be screened in stages, critically appraised using the Collaboration for Environmental Evidence Synthesis Assessment Tool (CEESAT), and coded using a predefined schema covering livestock species, production systems, value chain stages, geographies, and outcomes. Rather than aggregating effect sizes, the review will provide a configurative map of where synthesized evidence is concentrated, where important gaps remain, and which themes are most relevant for future livestock research, policy, and investment in LMICs.