Enteric methane - facts and solutions
At present, methane emissions from Irish dairy cows are predicted using international default emission factors. Here, Hazel Costigan and Ben Lahart explain how research in Teagasc Moorepark has found this figure to be substantially lower in grazing dairy cows.
These differences are primarily due to high quality grass, particularly in the spring period. This highlights the role of improved grassland management in reducing methane output.
Research also demonstrates that while genetically elite dairy cows for the economic breeding index (EBI) do not have a higher overall methane output, the greater milk solids output in the elite translates to less methane being produced per unit of milk solids.
Individual animal variation for methane is also apparent in grazing dairy cows, meaning it may be possible to genetically select for low methane emitting cows in the future.
Research with feed additives has demonstrated reductions of 22% to 25% when fed to animals within indoor systems, in which additives are mixed into a total mixed ration and, as such, present in the rumen throughout the day. At pasture, the most practical way of feeding additives is through supplemental feeding in the milking parlour twice daily, which may limit additive efficacy.
Research in Teagasc Moorepark has found that cows supplemented with additives produced significantly less methane for 2.5 hours after feeding. After this period, their methane emissions reverted back to normal. This shows that feed additives can reduce methane in grazing dairy cows. However, slow-release technologies are required to keep the additives working for longer. This study also highlighted the challenges in terms of additive delivery to grazing dairy cows, and is committed to finding practical solutions.
Moorepark Dairy Open Day
More information on this research will be presented at the upcoming Moorepark Dairy Open Day, which takes place on Tuesday, July 4th. The theme of this year’s event is ‘Securing a Sustainable Future’, with current (such as the above) and future technologies being presented on the day.
Along with a focus on grassland management – including precision nitrogen (N) management, the benefits of white clover and reducing farm gate N surplus – an emphasis will be placed on breeding and reproduction. EBI developments to improve sustainability, beef breeding indexes and the benefits and opportunities of sexed semen will be outlined.
Also read: Moorepark '23: Meeting challenges to secure a sustainable future
Also read: Laurence Shalloo on the challenges and opportunities facing the dairy industry
Also read: Higher milk solids yields from grass-white clover swards at Moorepark
Also read: Multispecies swards and methane emissions on Curtin's Farm
This article was adapted from the May/June issue of Today's Farm.
Photo caption: Hazel Costigan pictured in Teagasc Moorepark