New research maps methane emissions from Canadian dairy farms

The cheese, yogurt and milk produced on Canadian dairy farms all share a common ingredient: methane, an extremely potent greenhouse gas that contributes to global warming. But understanding how much is emitted from dairy farms and how to reduce it has proved difficult for the industry. Now, new research aims to fill the gap and pave the way for reduction.

While some individual dairy producers work to measure methane with on-ground techniques like collecting air samples, “there is absolutely no reliable way of measuring methane in the dairy industry right now, there is nothing,” said research co-author Suresh Neethirajan.

Using satellite data from NASA and the European Space Agency, researchers from Dalhousie University analyzed methane emissions from over 575 dairy farms and 384 dairy processors between 2019 and 2023. The data comes as the industry is staring down its target of net-zero emissions by 2050, but struggles to measure its methane output. 

The first step to solving any problem is quantifying it. Until now, the dairy industry has had no reliable way to measure emissions from entire farms, explained Neethirajan. Along with satellite data, the researchers used advanced machine learning techniques (AI) to map out trends. 

They found that Ontario’s dairy industry, which has more than 3,000 farms, is the highest methane emitter. A dairy farm with 100 cows emits an average of about 11,500 kilograms of methane in winter alone, the equivalent emissions of about 74 gasoline cars being driven for a year. Methane emissions on dairy farms are higher in the winter because cows are inside more often. When cattle graze and exercise more, their digestive process shifts and emissions drop, explained Neethirajan.

“So, the satellite data really helps us to understand how individual farms are doing. The comparative analysis between the sizes of the farms, between the provinces, and the formula we have come up with,” could help the government develop strategies for reducing methane in the industry, said Neethirajan, who said satellite data could serve as a “watchdog” for methane reduction targets. The study also includes a benchmarking tool, which they hope will aid the government in mapping out methane emission targets leading up to 2050, allowing them to create “carbon tax incentives and other strategies for farmers,” he explained. 

Taking into account the over 9,000 dairy farms that exist across Canada, it is clear that “the impact is huge. We really have to bring down the emissions,” explained Neethirajan.

Cows are agriculture’s biggest methane culprit: the world’s 940 million cows emit nearly 10 per cent of all greenhouse gas emissions, mostly through belches and droppings. 

In Canada, 10 per cent of greenhouse gas emissions are from crop and livestock production.

Reducing methane is key to reaching climate targets because of the greenhouse gas’ potency – it’s responsible for approximately a quarter of global warming and is over 80 times more powerful than carbon dioxide for the first 20 years in the atmosphere. 

Reducing Methane in the Dairy Industry

Just as measuring methane in the dairy industry is difficult, so is reducing it, explains Leluo Guan, a Canada Research Chair currently conducting a five-year study on methane reduction in cattle out of the University of British Columbia. Guan and her collaborators (who include researchers from across Canada) are collecting samples from cattle to see the methane in specific beef and dairy cows. This will then inform the development of measures to reduce methane.

Different cows have different levels of methane in their guts, just as human genetics differ from person to person. There are efforts to selectively breed cattle that emit less methane. 

However, the methane-slashing method that has been around the longest is feed additives, explains Guan. Cows are fed “all sorts of feed additives” to try and reduce methane: oils, fats, and plant extracts. 

The two most effective additives are 3-Nitrooxypropanol (3NOP), a synthetic organic compound approved early this year as a feed additive in Canada, and seaweed, Guan said.

While seaweed has been shown to be effective at slashing methane from cattle in some cases, it’s not a silver bullet solution and more research is still needed, explained Guan.

Seaweed has toxic compounds, such as chloride, she noted, and the impact it has on dairy or meat coming from cattle that consume it is still not understood, she said.

“So there's no evidence yet that when cattle are fed seaweed, the products are safe,” said Guan.

The rumen microbiome of cattle is complex, but working toward solutions is essential, agree Guan and Neethirajan. Unlike swapping oil and gas for renewables, there are no emission-free cows to replace the gassy cattle that make up Canada’s dairy industry.

Countries are trying different methods to reduce methane emissions in cattle through climate policy. In Denmark, for example, the government has developed a flatulence tax. From 2030 forward, farmers will pay per tonne of methane emitted from their livestock, including cows, a price that will rise from 300 kroner per tonne to 750 kroner in 2035. 

Canada isn’t looking at that model, which Neethirajan said would surely receive “heavy pushback.” Still, he says the government needs to develop a benchmarking system to incentivize farmers to “adopt strategies and ways to bring down methane emissions.”