Seaweed Could Help Farmers Tame Methane Emissions From Cow Burps

Cows don’t usually eat seaweed. But researchers at UC Davis want to change that in an effort to get the animals to burp smaller amounts of greenhouse gases.

Most cows on the campus dairy are fed the usual mixture of ingredients like alfalfa and corn. But twice a day a special set of a dozen cows are given the same feed, just mixed with a small dose of crushed seaweed and molasses to sweeten the salty mix.

The researchers ordered the seaweed from Australia. It comes in clumps and they crush it up and add a small amount to the cow's feed. Ezra David Romero / Capital Public Radio

“They are belching less,” says UC Davis animal science professor Ermias Kebreab. “What we see so far is a dramatic reduction. In fact, I asked my graduate student make sure these numbers are real.”

Kebreab says they’re burping about 30 percent less methane. He says 95 percent of the methane cows emit are from burps, the rest are flatulence.The reduction could be a big deal for California dairy farmers and other producers that are required to cut methane emissions by 40 percent by 2030.

“This is the beginning of a very exciting process that I hope will end up creating a new type of industry to supply seaweed in a form in which dairy cattle can take,” adds Kebreab.

They’re getting these results by measuring the cow’s breath.

Four times a day an open-air contraption drops “cow cookies” for them to eat. As the cows snack, the machine measures just how much methane they breathe out.

“We’re feeding doses between half a percent and 1 percent and it's proving to be as effective as the 2 to 5 percent in lab,” said Breanna Roque the PhD student running the daily operation. “That’s really exciting to see the seaweed actually working more effectively within the animal then in the controlled lab environment.”

She says even though the project is only a month and a half in the results are showing huge promise. The team will publish preliminary findings in June.