Some dairy cows produce 15% fewer methane emissions, but just as much milk

Embargoed until: Publicly released:

Cows produce methane emissions as a by-product of their digestion – and this methane is the largest contributor from the agricultural sector to greenhouse gases in both Ireland and New Zealand. Irish and Kiwi researchers ranked 45 Irish dairy cows by their residual methane emission (RME). This trait measures the difference between a cow’s expected and actual methane output. The cows in the low RME group produced 15% less methane than the high RME group, while maintaining milk production and feed conversion efficiency. The authors say that reducing methane emissions from dairy cows has the potential to play a large role in achieving the emission reduction targets set nationally and internationally, and further analysis is needed to find out why cows have different RMEs.

Journal/conference: New Zealand Journal of Agricultural Research

Link to research (DOI): 10.1080/00288233.2023.2277239

Organisation/s: Massey University, Teagasc, Animal and Grassland Research and Innovation Centre, Co., Cork, Ireland

Funder: The authors acknowledge the contribution of the farm staff at the Teagasc Moorepark research farm as well as a research grant from Science Foundation Ireland and the Department of Agriculture, Food and Marine on behalf of the Government of Ireland under the grant 16/RC/3835 (VistaMilk).

Media release

Comment from research lead author Katie Starsmore of Massey University, Teagasc and VistaMilk:

“Residual methane emissions is calculated by the difference between the expected and measured enteric methane produced per kg dry matter eaten.

“Residual methane has previously been identified as a trait that is not related to animal productivity traits such as milk production. The aim of this study was to investigate the ability of this trait to rank and select animals that are producing less methane per kg dry matter intake than expected and hence more efficient.

“The average dairy cow in this study was emitting 352g enteric methane per day and eating 16.6kg dry matter. Ranking animals based on their residual methane resulted in a reduction in daily methane output by 15% and no effect on productivity.

“Therefore, there are animals that are producing less methane than expected, while producing the same milk solids and weigh the same.”

SOURCE

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