Effect of 3-Nitrooxypropanol (3-NOP) Supplementation on Enteric Methane Emissions from Dairy Cows in Africa: A Systematic Review and Meta-Analysis
Year: 2026
Type: study-registration
Abstract: Description Sub-Saharan Africa holds a significant portion of the global livestock population; yet ruminant production systems in the region face major challenges regarding greenhouse gas (GHG) efficiency. Ruminants produce enteric methane (CH4) as a natural byproduct of microbial fermentation in the rumen. In African dairy systems characterized predominantly by smallholder, pasture-based, or low quality forage feeding methane yield per unit of milk produced is among the highest globally due to poor diet quality, high neutral detergent fiber (NDF) levels, and low digestible energy. The feed additive 3-Nitrooxypropanol (3-NOP) acts by directly inhibiting methyl-coenzyme M reductase (MCR), the key enzyme catalyzing the terminal step of methanogenesis in rumen archaea. While global meta-analyses in North America and Europe demonstrate that 3-NOP reduces enteric methane emissions by 20% to 40% without compromising milk yields, empirical data synthesized specifically under African nutritional conditions, forage diets, breed genotypes (e.g., indigenous Bos indicus vs. crossbreds), and management systems remain sparse and highly variable. Purpose To systematically identify, critically appraise, and quantitatively synthesize global and regional research on 3-NOP supplementation to evaluate its potential, efficacy, and context-dependent limitations for enteric methane mitigation in African dairy production systems. Expected outcome ●Quantitative Mitigation Baseline: A clear, evidence-based quantification of the expected percentage reduction in enteric methane yield attainable under sub-tropical and tropical African feeding regimes. ●Identification of Trade-offs: Clarity on how 3-NOP impacts feed efficiency, ruminal hydrogen (H2) accumulation, and energy partition toward milk production vs. methane loss. ●Policy and Strategic Insights: A foundational reference document for national GHG inventories (Tier 2/Tier 3 IPCC calculations), regional climate action plans, and livestock development strategies in Africa.
Source: Open Science Framework
Language: English
Subfield: Animal Science and Zoology
Domain: Life Sciences
SDGs: Zero hunger, Climate action
Open Access status: green
OpenAlex ID: W7214001032