Reducing methane emissions 'essential' in meeting agriculture’s target

Methane accounts for the majority of Irish agriculture’s greenhouse gas emissions.

It takes up approximately 63% of those emissions, so if we are to reduce total agricultural emissions by 25% by 2030, then reducing methane emissions will be essential in meeting these targets, according to Teagasc researcher Ben Lahart.

He was speaking at the Teagasc 'Farming for a better climate' conference on Tuesday in Tullamore.

At present, Ben explained that figures show that 6.3% of grass being digested by dairy cows is being released as methane – approximately 355g of methane/cow/day.

However, compiling Irish research findings, Ben explained that the figure is more likely 5.8% of grass being digested is being released as methane - 325g of methane/cow/day.

This means that Irish methane emissions are most likely lower than we currently think.

How to reduce methane emissions in grass-based systems?

Feed additives are becoming a well-known method of reducing methane. However, feed additives work most effectively for indoor diets.

They can result in a 5% to 6% reduction in emissions.

Ireland is focused on grass-based production systems and grassland management is essential to reduce methane emissions.

Ben explained that grazing the correct covers is essential. For example, methane emissions are low from spring grassland and begin to increase in May and June and reach a plateau for the remainder of the grazing season.

As a result, utilising spring grass can reduce emissions. Ben commented that supplementing grazing with grass silage in the spring will increase methane emissions.

He explained that grazing correct covers can make production more efficient. So, while methane emissions go up, the amount of methane produced per unit of milk solids can be reduced.

Bovaer

Ben was also asked to comment on Bovaer, a methane-reducing feed additive which is being reported to cause issues with cows in Denmark, where it has been compulsory in cows’ diets since 1 October.

He said that Teagasc has carried out six different trials on Bovaer and “never had any issues with it at all”. He said: “The research is clear in that regard.”

EBI and multispecies swards

Ben also noted that some multispecies swards can reduce methane emissions.

Research also shows that high-EBI herds produce less greenhouse gas emissions per unit of milk solids. He said high-EBI cows last longer in the herd, as they are more productive and there are fewer replacements.