Selecting for more methane efficient sheep

A bioeconomic model was developed to predict outcomes of scenarios to select for methane efficiency in Merino sheep. The model determines economic values for trait improvement according to different breeding objectives. A selection index approach is used to predict response to selection, assuming knowledge or assumptions about genetic parameters, economic values of breeding objective traits and phenotypic measurement information used to select animals, including information from reference populations for genomic selection. Breeding objectives were based on profit per DSE, reduction in overall flock methane output and methane production per kg lamb produced (defined here as methane efficiency). Results showed that methane production to produce a certain amount of lambs is affected not only by methane production per head, but also by reproductive rate. Methane output per kg lamb produced can be decreased by 3.5% per annum, with the effect of improving production and reproduction efficiency being stronger than the effect of reducing methane production per head.