New research may have found a way to reduce methane emissions from cattle, according to an NPR report. Methane is an even more potent greenhouse gas than carbon dioxide, and about a quarter of methane emissions in the US come from livestock. Worldwide, industrial livestock agriculture is considered one of the driving forces behind climate change.

Now, an experiment at the University of California, Davis has shown that cows that consume seaweed as part of their feed release considerably smaller amounts of methane into the air. The researchers, led by animal science professor Ermias Kebreab, divided 12 research cows into three groups. One group was given a high dose of seaweed, around one percent of their feed. Another received half that, and the third group received none. The experiment was carried out three times, each over a period of two weeks.

They then use a breathalyzer-like machine to measure gases from the breath of the cows.

Kebreab explains that contrary to popular notions, most of the methane from cows is released through belches. “Over 95 percent, actually, is from the mouth, from the front end of the cow,” he says.

The gas is produced as cows digest their fibrous food, in the first part of their four-part stomach, in a “natural process of fermentation.”

Following up on findings by Australian researchers, the team believed that seaweed might inhibit the chemical reaction that produces the gas.

They found that the high doses of seaweed reduced methane production by more than half, a “dramatic reduction in methane emissions,” according to Kebreab, that was far more significant than expected.

They also found, however, that the cows ate smaller portions, and produced less milk, as a result. Kebreab explains:

“It’s basically the palatability issue. It’s something that they haven’t had before, and when you have it at 1 percent they smell it. It smells like the ocean, I guess. That’s why our next work is going to be how to deliver the seaweed so they don’t notice it.”

The findings were presented at the annual American Dairy Science Association meeting, in Knoxville, Tennessee.

Blind taste tests were conducted to ensure that milk from the cows did not take on a seafood taste from the seaweed. The 25 panelists reported no unexpected taste from the milk.

California has introduced plans to reduce methane emissions by 40 percent from 2013 levels, by 2030. The new findings could have a significant impact on the state’s ability to meet that goal.

In the meantime, further research will be needed into the health and productivity of cows that eat seaweed, and the research team is planning a longer-term experiment that will look at beef cows instead of dairy. According to Kebreab, it will investigate “the long-term effects of seaweed on the health of the animals and the productivity of the animals.”





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