Shortlist of five holds key to reduced methane emissions from livestock

Research team members Ron Ronimus, Stefan Muetzel and Peter Janssen in front of the respiration chambers used to test methane-inhibiting compounds in sheep. Photo: Radio New Zealand/Veronika Meduna

AgResearch scientists have identified five different animal-safe compounds that can reduce methane emissions from sheep and cattle by 30 to 90%. Results from animal trials were presented at the 2015 New Zealand Agricultural Greenhouse Gas Mitigation Conference held in Palmerston North on 28 April.

Principal scientist Dr Peter Janssen, who co-ordinates the methane research programme, said the findings were the culmination of five years’ work, during which the team screened more than 100,000 compounds through computer-based searches and in laboratory experiments.

Developing inhibitors is one of four aims of the Pastoral Greenhouse Gas Research Consortium (PGgRc) and New Zealand Agricultural Greenhouse Gas Research Centre (NZAGRC) joint methane mitigation research programme. The programme also has aims of breeding low methane-emitting ruminants, identifying low greenhouse gas feeds, and developing a vaccine to reduce methane formation by the methanogens that live in the rumen of livestock.

The inhibitor work is led by AgResearch’s Dr Ron Ronimus. It is seeking new types of inhibitors of methane production that slow down or kill the methanogens, the microbes that generate the methane. Using the genetic information that became available when the first complete genome of a methanogen was published by the AgResearch team in 2010, they focussed on finding compounds that would inhibit methanogen function and leave the rest of the rumen system unaffected.

“The screening process identified five compounds that have now been tested successfully in sheep, showing a reduction in methane production over a two-day period from 30% to more than 90%.”

PGgRc Chairman and NZAGRC Steering Group member Dr Rick Pridmore says the successful test of methane inhibitors is news that New Zealand farmers can get excited about.

“The results are significant for two reasons. First, because they work on livestock consuming a grass-based diet and, second because the short-term trials showed such dramatic results.

“It must be stressed that these are early days. Further trials are needed to confirm that these compounds can reduce emissions in the long term, have no adverse effects on productivity and leave no residues in meat or milk.

“We are already looking to engage with a commercial partner and, all going well, we could possibly see a commercial product for use on-farm within five years.”

This significant research progress comes as a result of substantially increased government and farmer funding into agricultural greenhouse gas mitigation over the past five years. The research is funded by the jointly industry/government backed PGgRc and the wholly Government-funded NZAGRC. Collaboration between New Zealand and international scientists, made possible through New Zealand Government funding in support of the Global Research Alliance on agricultural greenhouse gases, was also critical for reaching this milestone.

The Ministry for Primary Industries’ International Policy Director and representative to the Global Research Alliance, Chris Carson, says “this is an exciting development and it is pleasing that funds made available by the New Zealand Government to support international cooperation in agricultural GHG research have played a role.”

The research team is now running trials to see if the inhibition effects last long-term and whether it will result in increased animal productivity as well.

“Methane produced by rumen methanogens represents about 9% of the dietary energy in the forage consumed by the animal,” says Peter.

“If some of that energy can be redirected to the animal, it may lead to an increase in the animal’s ability to produce meat, milk or wool. This would be a real win-win for farmers.”