ABSTRACT

Additional benefits could be achieved in reducing methane emissions if breeding values for methane emissions could be developed. However, building a sufficiently large dataset for genetic parameter estimation has been challenging, as phenotype data is scarce. New methods of detecting methane emissions are being developed, including gas sensors and radioactive tracers (SF6), which will enable enough phenotypes to be collected to estimate genetic parameters. For example, using a portable air sampler and analyser unit to measure methane emissions on 3121 cows from 20 herds, Lassen and Løvendahl (2016) estimated that the heritability of methane emissions varied between 0.16 (s.e. 0.04) and 0.21 (s.e. 0.06) for various methane emission traits. Including methane emissions in the selection objective may further reduce greenhouse gas emissions at a small economic cost.