Cows Plus Seaweed Take a Bite Out of Methane

Cows Fed Red Seaweed Produce 80% Less Methane!

Let’s talk cow burps. Not the most glamorous topic—but hang on, because this might be one of the weirdest, coolest, low-tech climate wins we’ve got.

Cows (and other cud-chewing ruminants) are responsible for a massive amount of methane emissions. And believe it or not, most of it comes out the front end. Yep—burping! And that methane? It’s a superpowered greenhouse gas, packing 80 times the heat-trapping punch of CO₂ in the short term.

So what’s the fix? A fancy machine? A futuristic pill? Nope. Red seaweed.Seriously.

Just a Spot of Seaweed

Turns out Asparagopsis taxiformis—a type of red seaweed that looks like underwater parsley—has a hidden talent: it messes with the enzymes in a cow’s stomach that create methane. Mix in just a sprinkle with a cow’s daily feed (less than 1%), and you can reduce methane emissions by up to 80%. That’s not a typo.

Seaweed? What Seaweed? Cows Don't Notice It!

• In trials, cows ate normally with seaweed in their feed—even at doses that slashed methane by over 80%.

• No changes in appetite, mood, or milk/meat quality.

• Some farmers say the cows are “happier,” but that’s anecdotal (and possibly because their guts are less gassy!).

Cows Might Even Digest More Efficiently.

• By reducing methane, cows are losing less energy during digestion (methane = wasted energy).

• That means more of what they eat gets used for growth and milk production—a win for the animal and the farmer.

But Wait... What About Not Eating Meat?

Okay, okay—we know this is already controversial territory. If you’ve generously given up meat for the planet, we salute you. That’s a deeply respectful goal, and it’s part of the solution.

But... we know humans. No matter how compelling the arguement, there’s a large population that eats meat. So, if we can reduce emissions that’s a win we’ll gladly take.

UC Davis: “Usurp the Burp!”- The Moo-ment That Changed the Methane Game

In Apri, 2015 Professor Ermias Kebreab and graduate student Breanna Roque at UC Davis became the first team to test Asparagopsis taxiformis (red seaweed) in real cows—a major leap after earlier lab-only studies. In one trial, adding just 1–2% seaweed to feed cut methane emissions by 50–82%, even across 21 weeks of daily feeding—with no drop-off in effect or cow health! 

They measured burps in real-time with fancy open-air machines that sniffed cow breath four times a day and found emissions plummeted—while cows kept gaining and growing normally.

Why was this research important:

If all beef and dairy cows in the U.S. were fed red seaweed (like Asparagopsis), methane emissions could be reduced by up to 2.98 million metric tons of methane per year

That’s the climate equivalent of taking:

• over 71 million gas-powered cars off the road for a year

• or shutting down dozens of coal-fired power plants

…just by tweaking what cows eat.

Seaweed Meets Sagebrush: Oregon State's Silver-Bullet Cows?

The research that Professor  Kebreab started continues. Researchers at Oregon State University are exploring other seaweeds. In a $1 million, five-year study, about 20 cows grazing on 100‑acre sagebrush pastures near Riley, Oregon are being given Pacific dulse seaweed, grown commercially along the Oregon Coast by Oregon Seaweed.

Pacific dulse seaweed is also a red seaweed. It is a type of marine macroalgae classified as belonging to the Rhodophyta division, which is the scientific term for red algae. Dulse is known for its reddish-purple color and is found along the rocky shores of both the Pacific and Atlantic coasts. What is the goal of the study? See if this ocean-grown supplement can cut methane emissions from burps—even when cows are roaming free, not just in feedlots. What if cows in eastern Oregon swapped ordinary grass for a seaweed-infused snack—and belched less methane into the atmosphere? Stay tuned!

Why it’s exciting:

• This is one of the first pasture-based seaweed trials (not just feedlot testing).

• Oregon has 1.2 million beef and dairy cows, making it ripe for climate impact if the experiment succeeds.

• Researchers will track methane and CO₂ levels right above the grazing land—and test whether soil carbon increases too. Plus, they’re using GPS collars, virtual fences, and flux towers like something out of a sci-fi meets science lab.

Blue Ocean Barns Brominata™: Moo-ving on Methane Now!

In the meantime, Blue Ocean Barns,based in Kona, Hawaii, is officially open for business for climate-conscious cattle farmers! Their seaweed supplement Brominata™—made from Asparagopsis taxiformis and proven to slash cow burp methane by around 80%—received a green light from the California Department of Food and Agriculture in 2022. That means it’s legally approved for sale and use in California dairy and beef operations, in both certified organic and non‑organic forms.

Funded with ~$20M in venture capital and fresh deals signed with mainland dairy producers and even Ben & Jerry’s, they're turning seaweed into one of Hawai‘i’s hottest climate solutions.

Symbrosia’s SeaGraze®: The Snack That Saves the Planet

Another Kona-based innovator, Symbrosia, grows SeaGraze®—a USDA Organic antimethanogenic supplement made from red seaweed. Their pilot trials with Parker Ranch cattle cut burp-related methane by about 77% over six months.Symbrosia’s cultivation happens onsite at NELHA (Natural Energy Lab of Hawai‘i Authority), where they plan to expand from a quarter-acre to 15 acres of seaweed farm—all while boosting livestock productivity and carbon neutrality goals.

The Wonder of Human Ingenuity

We tip our hats to the vegetarians and vegans leading the charge—your choices are powerful. At the same time, many people around the world still eat meat, and that’s not changing overnight. That’s where seaweed-fed cows come in: a surprising, science-backed way to shrink emissions.

If a sprinkle of seaweed can quiet the burps and keep everyone moo-ving forward, well—that’s a win that reminds us just how much wonder there is in human ingenuity.

*We’re a mission-driven nonprofit spotlighting climate solutions—we don’t sell products or take proceeds from the innovations we feature. Our goal is to foster dreamscrolling over doomscrolling, inspiring hope through human ingenuity.

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Climate of Wonder is a mission-driven nonprofit spotlighting climate solutions—we don’t sell products or take proceeds from the innovations we feature. Our goal is to foster dreamscrolling over doomscrolling, inspiring hope through human ingenuity.

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