Integrating Enteric Methane into Cattle Breeding Objectives for Climate-Smart Livestock Production

Enteric methane (CH4) emissions from dairy and beef cattle are a major source of agricultural greenhouse gases, creating a need for mitigation strategies that are effective, permanent, and economically sustainable. This review evaluates the current status of methane traits in cattle breeding programs and examines opportunities and challenges associated with incorporating methane into national breeding objectives. Published evidence on methane phenotyping technologies, quantitative genetics, genomic prediction, economic valuation, and international breeding initiatives was synthesized. In addition, mechanistic forecasting and Monte Carlo simulation models were used to assess the potential long-term contribution of methane-inclusive breeding programs to greenhouse gas mitigation under different genetic gain and adoption scenarios through 2050. Available evidence indicates that methane emissions are moderately heritable and amenable to genetic selection, yet methane remains absent from most commercial multi-trait selection indices. Simulation analyses suggest that incorporating methane-specific traits into breeding objectives could generate cumulative and permanent reductions in greenhouse gas emissions while increasing economic value under evolving carbon-pricing frameworks. Successful implementation will require expanded phenotyping, standardized genomic evaluations, appropriate index construction, and international collaboration. Integrating methane traits into national breeding objectives represents a practical and scalable strategy that complements nutritional, managerial, and technological mitigation approaches while supporting climate-smart, sustainable, and resilient cattle production.