Cow breathalyzers help scientists measure methane emissions

Jan. 10 (UPI) -- Researchers in Texas have developed new technology for measuring the amount of methane emitted into the atmosphere by cattle.

Though news headlines often focus on the release of methane from the bovine's backside, the majority of methane emitted by cattle -- 95 percent -- is released via a belch.

To more accurately measure the amounts of methane released by bovine burps, scientists with the USDA-ARS Conservation and Production Research Laboratory in Bushland, Texas, developed new technology called GreenFeed -- a breathalyzer for cows.

"Cattle are trained to put their head into an open hood (with food), and while they're there munching on the little treat the device is sampling their breath," Richard Todd, a research soil scientist at USDA, said in a news release. "Then we can calculate the methane emissions while they're inside."

The GreenFeed measurements alone weren't sufficient to accurately estimate the amount of methane emitted by individual cows, so researchers supplemented the data with mathematical models accounting for each cow's food intake and other influencing factors.

Scientists also designed models to analyze laser-tracked emissions rising from cattle herds. The algorithms effectively accounted for the influence of weather, wind direction and the positioning of individual cows, revealing a more accurate estimate of how much methane is emitted by each cow.

The data showed a cow's methane production is largely determined by how much and what the cow eats. As such, bovine emissions fluctuate throughout the different grassland seasons.

Researchers determined that cows fed corn produced only a third the amount of methane emitted by grass-fed cows.

"That's definitely a happy accident," Todd said. "I do not think that they remotely considering methane emissions. Corn's cheap, it's easy, and it's quick to feed them in feedlots."

But grasslands host bacteria that efficiently consume methane, making grassland environs a methane sink. Microbes in grassland soils likely offset some of the methane emitted by grass-fed cows.

Though bovine methane emissions pale in comparison to industrial CO2 emissions, a growing body of research suggests scientists are significantly underestimating natural sources of methane, including ice sheets and volcanic glaciers.

The problem of methane emissions isn't without solutions. Last year, scientists showed bovine methane emissions could be reduced by adding seaweed to cattle feed.