The first large-scale measurement and characterisation of methane emissions in Irish beef cattle conclusively shows that some beef cattle can produce up to 30% less methane emissions, on average, for the same level of productivity.
Progress has been made towards identifying and breeding these low methane-emitting beef cattle, which will improve the environmental sustainability of the national beef cattle herd, according to Irish researchers.
The study, one of the largest conducted on this subject globally, is led by Teagasc in collaboration with colleagues at University College Dublin (UCD) and the Irish Cattle Breeding Federation (ICBF).
Methane output and feed intake
To date, the genetic selection of low methane-emitting ruminant livestock has been limited by the relationship of methane output and feed intake, says Teagasc.
Teagasc Walsh scholar PhD student Paul Smith explained: “In general, on the same plane of nutrition, animals that consume more feed tend to produce more methane on a daily basis.
“This relationship has so far made it difficult to breed low methane-emitting animals without negatively impacting feed intake, which is a key driver of animal productivity, particularly in forage-based production systems.”
However, working collaboratively through the project ‘RumenPredict’, Teagasc’s professor Sinéad Waters, professor David Kenny, Paul Smith and Stuart Kirwan, along with UCD’s Dr Alan Kelly and the ICBF’s Dr Stephen Conroy, have made a breakthrough in quantifying beef cattle emissions.
The researchers have recently developed an approach which is capable of disentangling the relationship of feed intake with methane output.
The group can now show the benefits of utilising a new concept termed residual methane emissions (RME) to select low methane-emitting animals without impacting animal productivity.
This study is the first large-scale measurement of methane emissions in Irish beef cattle and one of the largest conducted worldwide.
Residual methane emissions can be defined as the difference between an animal’s actual and expected methane output, based on the quantity of feed that it consumes on a daily basis and its bodyweight.
Describing the study, Paul Smith explained how the group calculated RME values for 282 beef cattle undergoing feed efficiency and methane measurements at the ICBF progeny test centre in Tully, Co Kildare.
After ranking animals as high, medium and low on the basis of RME, low-RME animals produced 30% less methane, but maintained the same level of feed intake, feed efficiency, growth and carcase output as their high-ranking RME herd mates.
Discussing the significance of the findings, Teagasc researcher professor Waters said: “Considering the recent greenhouse gas emissions targets set out in the Government’s climate action plan and particularly our requirement to reduce biogenic methane, the RumenPredict project demonstrates the future potential to breed beef cattle with lower methane emissions.”
He said the new technology has now been deployed across Teagasc, UCD and ICBF research facilities, enhancing the national capacity to accurately measure methane emissions.
Teagasc head of animal and bioscience research professor David Kenny said that it will be critically important for the continued economic and environmental sustainability of Ireland’s multi-billion euro beef industry that we continue to apply state-of-the-art science to identify and breed from the most productive, yet low methane-emitting cattle.
Commenting on the future direction of the research, ICBF’s Dr Andrew Cromie said: “The next step will be to broaden the investigation into the relationship between RME and other important traits at a genomic level with a view to harnessing this information within our national beef cattle genetic selection indices.”