UNH researcher says seaweed may reduce methane from cow belches

Valley News Staff Writer
Published: 12/6/2021 9:35:39 PM
Modified: 12/6/2021 9:35:11 PM

Researchers across the Northeast are investigating whether feeding cows locally sourced seaweed can improve the quality of their milk while also reducing their methane emissions.

And it might also be good for their health.

André Brito, a professor at the University of New Hampshire, has been taking samples of the “rumen” in cows’ stomachs, measuring them into temperature-controlled test tubes, and dosing them with seaweed. By roughly simulating the bovine digestive system in a test tube, Brito and his colleagues can identify which seaweeds are worth feeding to cows — a much more expensive endeavor.

“Cows evolved with microbes that produce methane. Our intent here is not to obliterate methane, but to reduce it by 30% or 40%,” he said. “Methane stays in the atmosphere for about 10 years. That presents a short timeframe, and attracts much more warming than CO2 — it is almost 30 times more effective at trapping heat. If we’re able to come up with a 30% to 40% reduction in methane, that could have a cooling effect.”

The EPA in 2019 estimated that agriculture was responsible for 10% of the United States’ greenhouse gas emissions, while transportation, industry and electricity release 77% of America’s emissions. Livestock, including cows’ belches, account for about a quarter of that 10%.

Brito listed off studies that pointed to how seaweed could limit the methane that cows belch into the atmosphere. Researchers working with test tubes had achieved an almost 100% drop in methane emissions. But he emphasized that a test tube is only an approximation of a cow’s stomach. Still, other researchers achieved 80% reductions in beef cows and 40% in dairy cows.

“Seaweed has chemical compounds that slow or kill microbes (in the cows’ stomach) that produce methane. That’s why the methane drops,” he said. Seaweed would only be a small part of the cows’ diet or “total mixed ration” — at most 6%, he added.

But most other researchers on the seaweed/methane beat worked with Australian seaweed gathered from a warm ocean half the world away, and shipping feed so many thousand miles would undercut emission benefits, he explained.

“Can we do it with seaweed that is grown locally, that would be accessible and could also be farmed in aquaculture systems?” he asked, with a note of excitement. “To scale this up” from experiments to commercial dairy production, “you need to find a way to make seaweed at a large scale to feed a lot of animals” — and partnering with the regional aquaculture industry could be the answer.

For a feed to be “viable,” it has to be local, said Margaret Gladstone of Newmont Farm, a Fairlee dairy with nearly 1,500 cows. Although Gladstone had not heard of feeding cows seaweed, her farm already considers its environmental impact. It is 50% solar-powered and they move quickly to harrow manure into the soil before the nitrogen has a chance to burn off.

A nutritionist from Newmont Farm’s grain company helps them individualize their cows’ total mixed ration. Most recently, they have added whey, a byproduct from cheeses and yogurts. Gladstone said that the farm “relies” on the nutritionist’s advice to make sure that their cows are as healthy as can be.

“You’ve got to feed these girls good diets,” she said.

Kelp, a type of brown seaweed, is already a popular feed with many organic farmers in the Northeast because of its health benefits, Brito said. For some yet-to-be-deciphered reason, it reduces the levels of cortisol — a stress hormone — in cows and the quality of the milk improves.

The U.S. Department of Agriculture is fueling much of the multi-institutional research on seaweed and methane. Brito is collaborating with Maine-based Bigelow Laboratory for Ocean Sciences. There, researchers are working closely with seaweed growers and leading further studies with the support of a five-year $10 million USDA grant. UNH will conduct research with $700,000 of the grant.

Sabrina Greenwood, a specialist in ruminant nutrition at the University of Vermont, is the lead investigator on a second project Brito is part of; the USDA selected it for a $2.9 million grant. UNH’s portion is $800,000.

Meanwhile, Alix Contosta, a UNH ecologist, is investigating how feeding cows seaweed will affect the larger ecosystem. She pointed to a number of outstanding questions: How does that influence the soil — the nutrient cycling, the chemical composition of the manure, the plant growth? If cows stop burping methane, would it become more prevalent in their flatulence and remove any net benefit?

But looking at the big picture starts small: Contosta and her team spent the summer making micro-ecosystems in jars that they filled with dirt from local farms and manure from seaweed-fed cows. Next, they will take the experiment into the “real world,” which involves following cows, gathering their manure, and tilling it into cordoned-off plots.

Seaweed is not the only way to green cows’ digestive tracts. Brito noted that Royal DSM, a Dutch company, is marketing “Bovaer,” a feed additive that includes 3-nitrooxypropanol, or 3-NOP, a compound it developed that it says can reduce cows’ methane output by 30% for dairy cows and 90% for beef cows. Brazil recently approved the product, while it remains under review by the Food and Drug Administration.

Claire Potter is a Report for America corps member. She can be reached at cpotter@vnews.com or 603-727- 3242.

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