Laser beams and breathalyzers: measuring cow burps for climate science

By using laser beams and breathalyzers to measure cow burps, Alberta scientists hope to cut down on the harmful emissions created by Canada's cattle industry.

A group of researchers at the University of Alberta has helped develop a novel method for measuring the methane emissions of cattle, which account for 55 per cent of the total greenhouse gases produced by beef production in the country.

"All ruminants, all beef and dairy cattle, and herbivores that graze lands, emit, due to the fermentation of grass and other feeds that go into one of their four stomachs," said John Basarab, a University of Alberta professor and research scientist with Alberta Agriculture and Forestry at the Lacombe research station.

Now that we can measure this, we can find animals that emit more or less methane. We can actually genetically select for them.- John Basarab, researcher

"They ferment the feeds, and one of the byproducts of fermentation is methane. And of course, methane is a greenhouse gas — a fairly potent greenhouse gas."

Typically, these emissions have been measured by bringing cows, one-by-one, into a test chamber. 

But researchers had longstanding concerns these tests did not accurately reflect the emissions of burping bovines that were actually out roaming around in a field, acting normally.

"That is very expensive and time consuming, and of course it disrupts the animal's behaviour, and it can only be done over a short period of time … they're very pricey, but they're costly and invasive," Basarab said. 

So the research team — made up of scientists from Alberta Agriculture, Agriculture and Agri-Food Canada and Livestock Gentec — decided to bring the lab to the pasture instead.

Beamed up bovines

The team set up a laser beam — a GreenFeed Emissions Monitoring System — both upwind and downwind of a research herd of nearly 40 cattle to measure methane and carbon dioxide in the atmosphere.

At the same time, a breathalyzer of sorts was set up in the field. The contraption is a massive fume hood on wheels, which has a chamber just large enough for a cow to to be able to comfortably stick its head inside.

And, the contraption lures the cows into the feeder with the promise of feed pellets.

"The animal sticks its head in there, because it's looking for a treat," said Basarab.

"They get a little cup of feed, about 35 grams, and the animal continues to gobble it up. If it stays in there for 10 more seconds, it gets another cup."

As the animals catch a meal, radio trackers placed on each animal trigger a fan, which sucks in samples of all the gassy air in the chamber.

The animal stays in in the feeder for three to five minutes, gobbling up food and looking for more. Three or four hours later, it can get another cup of pellets. A computer measures the cow's gassy outputs. 

"The air goes up into a little sampling device, back to a infrared detector that gives real-time measurements," Basarab said. 

"Before, we would have to collect this air in a cannister of some type, take it back to the lab, and maybe two weeks later we would get an answer. Now, this is all real time."

Study could help reduce methane emissions

By monitoring short visits to the feeder several times a day for 14 days, researchers were able to better understand not only individual cows but the methane output of the entire test herd.

So far, the high-tech measuring tools have revealed that breeding animals that are more food efficient — that eat less than what's expected for their size — may reduce methane emissions by 10 to 15 per cent over 15 to 25 years of selective breeding.

A year into the study, Basarab said thousands of test subjects will be required before the genetic profile of the right kind of cow can be pinned down, but he's pleased with the results so far.

"Now that we can measure this, we can find animals that emit more or less methane," said Basarab. "We can actually genetically select for them.

"These new methods are less expensive, less invasive, and I think they give us some pretty good measurements."