Research holds key to reducing cattle greenhouse gas emissions

VISITORS to the Teagasc research facility in north Cork might be forgiven for thinking they had stumbled onto the set of a low budget B-movie — maybe called something like Moooon Landing: Bovines With Backpacks.

This Teagasc project may look a bit odd to the passer-by, but it could yet prove invaluable in helping Ireland deliver on its commitments to reduce greenhouse gas (GHG) emissions, with a target of 20% below 1990 levels by the year 2020.

Teagasc’s findings suggest that cattle grazing on low maturity grass produce less methane. The study could help Ireland’s drive for increased milk production, while also helping to decrease GHG emissions, two major challenges for the Irish dairy industry.

Matthew Deighton of Teagasc’s Animal and Grassland Research and Innovation Centre, Moorepark, said: “Managing pasture swards to maintain low herbage mass and high leaf to stem ratio may represent a simple, yet important, tool in optimising the GHG efficiency of milk production.

“Low maturity grass fed to cows resulted in 9.4% less methane gas than a sward grazed at a high maturity. This resulted in a 13.9% reduction in the methane intensity of milk solids production due to a faster grazing rotation.”

In an article for TResearch, Teagasc’s science magazine, researchers outline how the adoption of currently available best management practices, such as earlier calving, reduced replacement rate; higher stocking rate and longer grazing season, provide scope for Irish milk producers to contribute to achieving target reductions in greenhouse gases without necessarily having to limit the overall output of milk solids.

Research designed to reduce the methane emission intensity of milk production has been under way at the Teagasc centre at Moorepark since 2008.

The aim is to investigate practical mitigation options for Irish dairy farmers to drive industry efficiencies. An increased focus on reducing emissions per unit product will result in the maximum reduction in global emissions.

The Teagasc Roadmap for Dairying defined performance improvements in manufacturing milk herds and targets an industry GHG efficiency of 13.53 kg CO2 equivalents per kg milk solids produced by 2018. This compares with a current average of 16.06kg.

A study to compare the relative efficiency of three different breeds, in terms of GHG efficiency, is currently under way.