Cows burp. Methane comes out. But feeding them seaweed drastically reduces the gas.

San Francisco Chronicle

Beef and dairy production are considered important drivers of climate change, contributing roughly 5% of U.S. greenhouse gas emissions, mostly in the form of methane released by cattle and other ruminant animals. But adding just a small amount of seaweed to cattle feed can reduce the output of methane in their burps by 82%, a UC Davis study published Wednesday concludes.

“We have a billion cattle in the world, and if even a few of them get it, it will make a big difference,” said Ermias Kebreab, co-author of the study and an animal science professor at UC Davis. Kebreab and graduate student Breanna Roque added a dried and powdered seaweed supplement to beef cattle’s feed over five months. The seaweed inhibits an enzyme in the cow’s digestive system that contributes to methane production in the form of burps.

Kebreab published a similar study using dairy cattle in 2019 that showed a 50% reduction in methane in cow burps, while the new one showed a larger impact and demonstrated that it can be sustained over a cow’s lifetime, he said. Neither the cattle’s beef nor milk took on the flavor of seaweed in either study.

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