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Could feeding seaweed to cows help reduce greenhouse gas emissions?

UNH scientists are studying the impacts of feeding seaweed to dairy cows.
Courtesy of the University of New Hampshire
UNH scientists are studying the impacts of feeding seaweed to dairy cows.

Using two grants from the USDA, scientists from the University of New Hampshire will study how including seaweed in the diet of dairy cows could reduce methane emissions.

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“If we can find ways to reduce the amount of methane coming out of cows, we can really contribute to solutions to combat climate change,” said Alix Contosta, a researcher on the project.

Cows produce methane as a part of their natural digestion process, as the microorganisms in their stomach produce the gas. They mostly emit methane through their burps.

“The stomach of a cow is basically a huge fermentation vat,” said André Brito, who leads the study with Contosta.

The U.N. Environment Programme has said reducing methane emissions is an effective way to slow climate change. Meanwhile, agriculture accounts forabout 10% of greenhouse gas emissions in the United States, according to the EPA.

Methane is a powerful greenhouse gas, but it stays in the atmosphere for a shorter period of time than other gases, like carbon dioxide. A reduction in methane could help rapidly reduce the rate of climate change in the short term.

UNH will work on the two projects to study dairy cows in collaboration with other institutions like the University of Vermont and Colby College.

One will focus on organic dairy farms, where feeding cows kelp meal is already a common practice, according to UNH. Scientists will study different species of seaweed that cows could consume.

The other will investigate conventional dairy farms, and the way algae-based feed might impact the quality of milk and the sustainability of the industry.

One of the ways to reduce methane is to reduce the microbial population that produces methane in the cow’s stomach. And some seaweed has chemicals with antimicrobial properties, which could reduce the population of microorganisms that produce methane, Brito says.

Previous research on seaweed for cows has shown promising results from Australian red seaweed, said Brito. But UNH researchers are using seaweed from the Gulf of Maine, which could provide a more sustainable solution for dairy farmers in New England.

To find out what the impact of seaweed is on the gas that cows produce, scientists will use special equipment to collect the cows’ burps and measure the quantity of methane in them.

The team will also study how seaweed could impact the animals’ health and milk quality, and how it could change the nutrient profiles of their manure, which might impact soil health.

“We’re trying to understand — is there a net benefit?” said Alix Contosta. “Really trying to follow the story as it moves from the seaweed into the cow, through the cow, out the back end, onto the field, and so on.”

Researchers will also look into the industry, taking into account the production and distribution of seaweed, and looking at how greenhouse gas emissions might look not only at the level of a cow, but at the level of the whole system.

But has anyone asked what the cows think?

“They don’t mind the seaweed,” Brito said.

Mara Hoplamazian reports on climate change, energy, and the environment for NHPR.
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