Science: Seaweed cuts cow methane emissions by over 30%

One way that scientists have been trying to fight climate change is by finding ways to limit methane gas emissions in cattle — in other words, by making cows burp less. Making a totally belch-less bovine is impossible, but dietary changes can limit the gas emitted.

Seaweed and algae have long been proposed as ingredients that could be introduced to cattle feed to reduce methane, thanks to a compound found in some seaweed that disrupts enzymes used by microbes to produce the greenhouse gas.

Now, a recent study from the University of California, Davis has found that just a bit of seaweed can reduce cow methane emissions by “well over 30%.

“Results are not final, but so far we are seeing substantial emission reductions,” said study lead Ermias Kebreab. “This could help California’s dairy farmers meet new methane-emission standards and sustainably produce the dairy products we need to feed the world.”

The researchers brought 12 Holstein cows into their special seaweed diet program. Though the idea of using seaweed has been around for a while, for years it had only been tested in synthesized cow stomachs. This study is the first to use live animals.

With the seaweed diet, about half a pound of a seaweed/molasses mixture was introduced to the feed supply, so about 1% of the roughly 50 pounds of feed that a cow consumes daily. Kebreab says increasing this mixture to 2% could cut methane emissions further. He and his team reassure farmers that they’ve observed no drop in milk yields of the animals they’ve fed the diet.

“You’re not changing the main diet of the animal,” he said. “It’s just a matter of mixing the additive to their diet and providing the seaweed.”

More research is planned to determine how the seaweed additives might affect cattle long-term. The next trial will focus on steers.

“We have much more research to do to determine if seaweed supplements could provide a viable, long-term solution,” Kebreab said. “But we are very encouraged by these early results.”

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