Methane Research Programme

The NZAGRC methane programme is jointly planned and funded in partnership with the PGgRc and aligns with existing MPI programmes funded through SLMACC and New Zealand funding in support of the Global Research Alliance on agricultural greenhouse gases. It aims to reduce emissions by directly targeting the methane producing methanogens through the discovery of small molecule inhibitors and vaccines and indirectly through feeding and changes in animal phenotype. 


  • Breeding: Research to understand the genetics of host control of ruminant methane emissions, which aims to develop genetic and genomic selection technologies to reduce methane yield and intensity in sheep. The current stage of the programme involves the development and dissemination of practical tools for selection for lowered emissions. A major part of maximising impact and uptake is to explore relative economic value from increased production and potential increased feed utilisation associated with lowered methane
  • Vaccine (jointly supported by PGgRc): A prototype vaccine (which after further development is aimed at producing a vaccine targeted at reducing methane emissions in cattle and sheep by 20%) is being formulated with the help of a commercial partner
  • Inhibitors (previously jointly funded but now fully funded by PGgRc): Research to develop cost-effective inhibitors that reduce methane emissions by at least 20% in sheep and cattle—without reducing productivity—is now being developed, with a view to bring the technology to market
  • Modelling: A tool to help scientists in the NZAGRC/PGgRc programme to develop hypotheses and predict responses in methane formation is in its final stages
Current progress and research stories

The current objectives within the NZAGRC methane programme have made significant progress this year, with the sheep breeding programme getting closer to delivering breeding values to the national flock.

Recognition for world-renowned animal geneticist

A major force behind many ground breaking advances in animal genetics is being recognised with a Science NZ Lifetime Achievement award this month.

John McEwan, a principal scientist at AgResearch Invermay, has devoted his career to genomic research with the aim of improving the genetic merit of livestock—particularly sheep—in New Zealand and around the world. Up until recently he was also co-leading the low methane emitting sheep breeding programme, jointly funded by the New Zealand Agricultural Greenhouse Gas Research Centre (NZAGRC) and the Pastoral Greenhouse Gas Research Consortium (PGgRc). 

The youngest son of Southland Romney stud breeders, John decided to pursue a career in science instead of following in the family farming footsteps, and studied chemistry and biochemistry at Otago University. 

He describes the early part of his career as “chasing sheep around paddocks to estimate their breeding value”, and for a year was a secondary school teacher in Invercargill. For the past 20 years John’s work has been more laboratory-based, focusing on genetics. 

In 1999 John was one of a number of people who helped establish Sheep Improvement Limited (SIL; now part of Beef+Lamb NZ Genetics). He designed its computational framework and with Sheryl Anne Newman wrote much of the genetic evaluation code that helped the organisation get off the ground. 

“I’d say SIL brought some significant financial benefits to the sheep farming industry,” says John. “There’s pretty good evidence that the changes that were implemented as a result have made a major impact on the animals that we now have in New Zealand.” 

Some of his other achievements include managing New Zealand’s contribution to sequencing the cattle genome, and being part of a similar international effort to map the sheep genome. John and other AgResearch staff were co-authors on a series of 3 papers published in the prestigious international journal, Science, about this work. 

The sequencing of sheep and subsequent work helped identify more than 30 million DNA variants and has led to some very valuable spin-offs for New Zealand agriculture, including the development of a number of commercial tests that are now available to the sheep industry. 

“We were able to create low, medium and high density ovine SNP (single nucleotide polymorphism) chips, which have allowed us to quickly and cheaply screen sheep for useful genes,” explains John. 

SNP chips have helped transform the future selection and breeding of sheep. “This technology is useful for identifying hard-to-measure traits that aren’t normally recorded until later in the animal’s life, such as longevity, disease resistance, meat quality and reproduction.” The low and medium density SNP chips are predicted to generate around $200 million for the New Zealand sheep farming industry over the next decade. 

Similar genomic tools, but using DNA sequencing, developed more recently by the group are now commercially available for breeders and researchers in over 50 species and are being used in a range of other production industries including deer, goat and salmon as well as ryegrass and clover seed production. 

John’s expertise on genomic selection also proved very useful for the NZAGRC-PGgRc low methane sheep breeding programme. His research involves determining whether the amount of methane emitted by individual animals can be changed through selective breeding, and what impact that would have on other productive traits. 

“It had been known for some time that some individual animals produced more or less methane than others, so the first question was, can we breed for this? And the other was, how did they produce more or less methane?” says John. “We were able to establish that low methane production is a heritable and repeatable trait, and that the low emitting sheep have similar or higher productivity, have rumens that are around 20 percent smaller, have different rumen microbial communities and have different volatile fatty acid (VFA) concentrations in the rumen.” 

John is currently investigating ways to make the rumen microbial sequencing process cheaper.

“Historically it would probably cost a couple of hundred dollars per animal, which is never going to be practical, so over the past six months our group has been coming up with ways to modify our low cost genotyping by sequencing process so that it can be used on the bacteria in rumen,” explains John. “It’s looking pretty promising—it’ll hopefully help us get a better handle on exactly how the animals produce less methane, which will make the selection process a lot easier than putting animals in a plastic box to measure their emissions.” 

John says he feels very lucky that just about everything he’s worked on in his career has ended up being implemented in industry. 

“You start to get a feel for what works and what doesn’t work. You might have a fancy, glitzy idea but you’ve actually got to convince people that it works. It might be something that’s good for the industry as a whole but farmers have got to be convinced of the benefits—they’ve got to know that they’ll get paid for it. Seeing money in their pockets is a great motivator, so that is our challenge as scientists—especially for solutions to low methane emissions.” 

He says the reality of working in breeding is that it’s quite slow. 

“You’ve got to be pretty cautious and pretty sure that you’re going in the right direction, because you don’t want to be 10 or 15 years down the track and realise it hasn’t worked out how you wanted it to.” 

The award, which will be presented to John at a ceremony on November 9 at Te Papa in Wellington, is part of a Science NZ celebration marking 25 years of Crown Research Institutes (CRIs) in New Zealand. He’ll be one of three award recipients from AgResearch, and says it’s an honour. 

“It’s pretty nice to get that recognition. I look at it as acknowledgement of the whole team of people behind this work, and the impact it’s had on industry,” he says. “The award’s probably just got my name on it because I’ve been around longer than everybody else!”

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