In The Country: Reducing Methane Emissions with Seaweed

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Dairy farms and other livestock operations are major sources of methane, a potent greenhouse gas produced when cattle burp, pass gas or make manure. This is why California is requiring farmers to reduce methane emissions by 40% by 2030.

As a means to help reduce methane’s impact on the environment, students and researchers at the University of California-Davis (UC-Davis) are feeding seaweed to dairy cattle to see if this unique diet could help reduce methane emissions.

“Reducing methane ultimately means reducing greenhouse gases and reducing the impacts of climate change,” says Ermia Kebreab, UC-Davis dairy scientist. “It affects everybody across the globe.”

Before the seaweed is fed to the cattle, it is first tested in a lab where emissions are measured in fermenters that simulate cow stomachs. “We can test the effect of different feed additives on gut microbiology,” says Matthias Hess, UC-Davis microbiologist, who uses these ‘robot rumen’ machines to measure methane content.

Mixing the seaweed with molasses, the cattle are fedthe additive at the rate of either 0.5 or 1.0% of their dry matter intake. Using feeding machines to measure the methane content of the cow’s breath, researchers record individual methane emissions for each animal.

“So far it is very encouraging,” Kebreab says.” We’ve seen over 30% of reduction in methane emissions.”

At the University of Wisconsin, researchers are studying how cows breathe along with what and how much they eat effects their emissions.

“Really what drives the emissions from the cow is how much the cow eats,” says Michel Wattiaux, University of Wisconsin-Madison dairy scientist. “The more the cow eats, the more she needs to process that feed and the more methane she is going to produce.”

While the results of this study are promising, they are not final. However, they do indicate that just a touch of the ocean algae added to cattle feed could dramatically cut greenhouse gas emissions from California’s 1.8 million dairy cows.

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