California scientists hope feeding cows seaweed will make them less gassy — which could be great news for the environment

Key Points
  • Researchers in California are testing whether seaweed in cow diets can reduce climate pollutants.
  • The state's livestock sector — mostly the dairy sector — is responsible for an estimated 55 percent of methane emissions in the state.
  • Methane is created in cattle production when cows burp, pass gas and poop.
  • Preliminary findings show a touch of seaweed added to the cattle's diet may reduce cow gassiness by "well over 30 percent."
Dairy cow inside research barn at University of California at Davis, where they are studying ways to reduce methane emissions from gassy cows.
Gregory Urquiaga | UC Davis

California is pushing for a reduction in greenhouse gases generated from cows, and adding seaweed to the cattle's feed shows promise in reducing potent methane emissions by more than 30 percent, researchers said this week.

Based on preliminary results, the seaweed could help dairy operations cut the level of methane emissions to meet California's new standards. The state's livestock sector — mostly the dairy sector — is responsible for an estimated 55 percent of methane emissions in the state, according to a report from the California Air Resources Board.

Methane is created in cattle production when cows pass gas, belch and defecate. While methane can be short-lived as a climate pollutant, it is considered at least 25 times more potent as a heat-trapping gas than carbon dioxide.

"From the cows, half of the methane emissions is from the belching of the animal and the other half is from the manure," said Ermias Kebreab, one of the researchers behind cows consuming seaweed and an animal science professor at the University of California-Davis. "You can use additives such as seaweed to try to reduce the methane that's belched out of the animal."

Kebreab and his team are demonstrating the seaweed project this week and plan to publish preliminary findings in late June and begin further tests with additional cattle later this summer.

According to Kebreab, the project is supported by several nonprofits, including Elm Innovations, an organization associated with Stanford University. Another contributor is the 11th Hour Project — a program of the Schmidt Family Foundation, a private foundation created by former Google CEO Eric Schmidt.

"This is really the first trial on dairy cattle that's been done ever in the world," Kebreab said. "From what I've seen so far, it seems to work quite well. But there's a lot of stuff we need to do before this can be a viable solution."

A significant cut in gas, and the milk still flows

Based on preliminary findings, Kebreab said a touch of seaweed added to the cattle's diet appears to reduce dairy cows' gassiness by "well over 30 percent."

Kebreab said the methane emissions could be lowered even more by increasing the seaweed concentration used from about 1 percent to 2 percent of the cow's diet.

The researcher said cows usually consume about 50 pounds of feed per day, and the seaweed mixture represents only around half a pound of the animal's diet. There's been no drop in milk yields on the cows using the seaweed additive.

Ermias Kebreab, University of California at Davis animal science professor, who is studying ways to reduce methane emissions from gassy cows.
Gregory Urquiaga | UC Davis

"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."

New standards to meet

The use of seaweed could help California dairy farmers as they face new standards to cut methane emissions.

In 2016, California set targets for cutting methane emissions as part of an effort to reduce statewide emissions of short-lived climate pollutants across industries, including the dairy sector. The goal is to cut the level of methane emissions 40 percent below 2013 levels by 2030, and the state believes 75 percent of that reduction should come from the dairy sector.

Dairy farmers fought against the tougher rules and argued at the time it would increase costs of doing business. The legislation was signed into law at a time when more dairy farmers were exiting the business or moving to other states.

"There are environmental costs of operating here and extremely high land costs, and feeds need to be brought in," said Ray Souza, a longtime dairy farmer in Turlock, California, who left the business in 2016 and now rents his dairy facility. "It just makes it more difficult for California to compete with the Midwest today."

California, the leading dairy state, is home to about 1.8 million milk cows and accounts for nearly 20 percent of the nation's milk production. The state also has more than 5 million beef cattle.

"California is a huge producer of dairy, and so when you just add up all the methane emissions that you have there and the amount of production that's happening, you can see how it can be a really significant contributor to those overall climate pollutants," said Marcia DeLonge, a senior scientist in the Food and Environment Program at the Union of Concerned Scientists, a Washington-based advocacy and research group.

The state had 1,390 licensed dairies last year, down 30 dairies from the year-ago period. It has lost 173 dairies since 2012, according to the California Department of Food and Agriculture.

Some of the dairy operations that left California have located in states such as South Dakota, Iowa, Idaho and Nebraska. Those states do not have the stringent air and water quality rules found in California, including the requirement to cut greenhouse gas levels from livestock manure.

"California has a specific mandate to reduce methane emissions," Kebreab said. "So if we prove this works and becomes cost effective, then you could probably just use this additive to meet that mandate. You don't have to do anything else."

Other ways to cut livestock methane

Another way the state is fighting global warming is encouraging the use of so-called dairy digesters, which essentially trap methane gas as it forms and channel it into use as a fuel source. The state set up a polluter fee fund from its cap-and-trade program that provided financial aid for dairy operators to buy the technology that can trap the methane gas and produce electricity.

A single adult dairy cow can release 70 to 120 kilograms of methane emissions each year. That's equivalent to the carbon footprint of a car driving about 7,800 miles.

"People are interested in finding solutions with livestock since we produce so much and they have a big footprint," DeLonge said. "So any small change that you can make can make a really big difference in the climate impact that we see in these areas."

However, using the seaweed unleashes an active ingredient that blocks microbes living in the cow's stomach from creating methane. The microbes help the animal break down grass and other plant food through fermentation.

Close-up of seaweed feed mixture used in University of California at Davis research that seeks to reduce greenhouse gas emissions from dairy cows.
Gregory Urquiaga | UC Davis

A garlic extract fed to cows also has been researched as a way to alter methane-producing microbes in cattle. There's also been more focus recently on cow genetics as a way to reduce methane emissions.

A dozen cows are part of the seaweed research at UC-Davis, and they are separated into three groups: two groups fed various doses of the dried seaweed and one group given a regular diet free of the additive. Researchers are using an open-air contraption to measure the methane in the cow's breath as they eat.

Researchers also plan to see whether the taste of milk is different using the seaweed additive.

The cost of the seaweed is considered high at the moment because it needs to be harvested and transported, although Kebreab said the idea is to grow it commercially. He said there's been some interest in growing it in waters off Southern California.

"Up to now there hasn't been any market for it, so there was no reason to grow this," he said. "If we prove that this actually works, and works as intended, and there are no harmful effects to the animal, then there will be demand for it, and therefore there will be more research and work that would try to bring the cost down."