Scientists tackle cattle methane by targeting microbes in a cow’s stomach

When Leluo Guan peers inside a cow’s stomach, she sees more than microbes – she sees an opportunity to cut methane emissions from cattle and improve profits for beef and dairy farmers.

Cattle are central to food systems around the globe. In Canada, the beef and dairy industries contribute more than $50 billion to the country’s annual GDP, and support thousands of jobs from coast to coast. But cattle also account for more than half of Canada’s agricultural methane emissions – a greenhouse gas 28 times more potent than carbon dioxide in the near-term.

For farmers navigating high feed costs, droughts and trade pressures, methane is both a climate challenge and an economic problem.

“In a cow’s stomach, microbes turn feed into energy for growth and milk production, but they also produce methane as a byproduct,” said Guan, a professor in the University of British Columbia’s Faculty of Land and Food Systems. “That methane represents wasted feed energy.”

With feed accounting for 50 to 70 per cent of a farm’s operating costs, even small gains in feed efficiency could deliver substantial savings – while also cutting emissions. Demand for climate-friendly foods is also rising, creating a competitive advantage for producers who cut emissions.

That’s why Guan is leading a $7.9-million, federally-funded initiative to develop affordable, practical tools to reduce methane emissions and boost feed efficiency in cattle. Anchored at UBC, the project brings together researchers from the universities of Alberta, Guelph, Manitoba and Saskatchewan, Agriculture and Agri-Foods Canada and industry partners Semex and Lactanet.

“We’re creating innovative biotech tools to fine-tune the microbes in a cow’s stomach so less methane is produced and more energy is available for animal growth,” said Guan. “That’s a win for farmers, consumers and the climate.”

The cow burp problem

Guan would like to clear the air: it’s cow burps that are the problem, not emissions from the rear-end. A 100-cow dairy farm emits roughly 11,500 kilograms of methane each winter; that’s about the same as 74 gasoline cars. Scaled across Canada’s 11 million cattle, the environmental and economic impact is substantial.

While feed additives have been explored as mitigation tools, none have proven consistently effective, affordable and practical outside controlled feedlots. In Canada, where cattle often graze on pasture or winter forage, solutions must be flexible and low-touch.

“Farmers want to be part of the climate solution,” said Guan. “But they need tools that are affordable, easy to use and supportive of animal health and productivity.”

That need has shaped a team whose expertise spans genomics, animal breeding, productivity and welfare, data science and economics, including UBC researchers Drs. Marina von Keyserlingk, O.C., Daniel Weary and Ronaldo Cerri, along with UBC postdoctoral fellows and graduate students.

Their goal is to tweak the microbial ecosystem inside a cow’s stomach so more energy from feed is available for growth and milk production, and less is wasted as methane. Their focus is the rumen, the first chamber of a cow’s stomach, where 95 per cent of methane is produced.

To better understand that complex microbial system, the team has created Canada’s first national rumen microbiome database with samples from more than 10,000 cattle nationwide. Using that data, they are building predictive models to examine how microbes and cattle genetics interact to influence methane production and feed efficiency.

From lab to pasture

That science underpins a suite of complementary tools the team is creating, designed to work together on a farm.

One approached uses RNA inference and antisense molecules that act like “dimmer switches” and reduce the activity of genes methane-producing microbes rely on.

A second approach uses custom microbial blends – think of them like probiotics for cows – that promote more efficient digestion.

A third approach uses phages – naturally occurring viruses that selectively target methane-forming microbes without disrupting the broader rumen ecosystem.

Some cows also naturally produce less methane, so the team is identifying the genetic traits linked to those lower levels. Guan’s previous work shows these rumen microbe traits are partially heritable, which could help breeders build lower-emitting herds.

To make methane reduction practical on farms, the team is also testing low-cost tools like methane “sniffers” that measure gas in a cow’s breath, while developing simple rapid saliva tests to identify high- and low-emitting animals.

The team aims to finalize early formulations by the end of 2026, and begin real-world trials in 2027 at UBC’s Dairy Education and Research Centre in Agassiz, B.C. —a working dairy farm with nearly 500 cows and the infrastructure needed to study emissions, nutrition, genetics and animal behaviour.

“These tools give farmers a comprehensive strategy – combining the right genetics, microbiome interventions and management practices – to cut methane emissions by up to 30 per cent in dairy cows and 40 per cent in beef cattle, supporting Canada’s goal of a net-zero economy by 2050,” said Guan.

Positioning Canadian agriculture for the future

Guan is also collaborating with international partners, including the European Union’s Horizon HoloRuminant initiative and the U.S.-led Greener Cattle Initiative, supporting global efforts to build climate-smart livestock systems.

Cutting methane is one of the fastest ways to slow warming in the near term. As carbon markets evolve, farmers who reduce emissions could gain access to new revenue streams, strengthening Canada’s position in global food markets.

“Reducing methane isn’t just a climate commitment,” said Guan. “It’s an economic opportunity. When we help cattle use their feed more efficiently, farmers save money – and the whole sector becomes stronger.”