Fecha de publicación: -- Fuente: "milk OR dairy products" J Dairy Res. 2026 Nov 9:1-19. doi: 10.1017/S0022029926102519. Online ahead of print.ABSTRACTDairy cattle significantly contribute to global greenhouse gas emissions, particularly methane. Genetic selection represents a permanent and cumulative strategy to mitigate emissions and improve dairy sustainability. This study aimed to synthesise genetic parameters of methane emission traits, evaluate their relationships with economically important traits and assess their potential inclusion in dairy cattle breeding programmes. A systematic review of 50 studies, selected from 895 screened records, was conducted to evaluate methane-related traits in dairy cattle. Traits examined included methane production (MeP), methane yield (MeY), methane intensity (MeI), methane concentration (MeC), residual methane, genetically standardised methane and the CH₄/CO₂ ratio. Heritability estimates for MeP (g/d) ranged from 0.11 to 0.49 in first lactation and 0.14 to 0.36 in second lactation. MeY (g CH₄/kg DMI) ranged from 0.21 to 0.42, and MeI (g CH₄/kg milk) showed similar heritability (∼0.21). Heritability of MeC varied with measurement method (0.11-0.32). Residual methane traits exhibited low to moderate heritability (0.10-0.21) but high genetic correlations across lactations (>0.92). MeP and MeI can be incorporated into breeding goals with limited evidence of adverse effects. Selection for reduced residual feed intake may decrease methane emissions but requires careful management to avoid negative energy balance. Ratio traits such as MeY present challenges for selection, whereas reductions in MeI are often driven by increased milk yield. Residual methane traits, adjusted for milk yield and body weight, represent a more robust alternative but require large datasets. MeC is a promising indicator due to its suitability for automated measurement, although it is sensitive to management conditions. Incorporating methane traits into selection indices can accelerate emissions reduction, particularly when supported by economic incentives. Trait prioritisation varies across countries depending on data availability and implementation constraints, with residual methane and MeC emerging as key candidates.PMID:43001420 | DOI:10.1017/S0022029926102519