Seaweed could make cows burp less methane and cut their carbon hoofprint

From MIT Technology Review


Sustainable Energy

Seaweed could make cows burp less methane and cut their carbon hoofprint

A diet supplemented with red algae could lessen the huge amounts of greenhouse gases emitted by cows and sheep, if we can just figure out how to grow enough.

by James Temple   November 23, 2018

In a wooden barn on the edge of campus at the University of California, Davis, cattle line up at their assigned feed slots to snatch mouthfuls of alfalfa hay.

This past spring, several of these Holstein dairy cows participated in a study to test a promising path to reducing methane emissions from livestock, a huge source of the greenhouse gases driving climate change. By adding a small amount of seaweed to the animals’ feed, researchers found, they could cut the cows’ methane production by nearly 60%.

Each year, livestock production pumps out greenhouse gases with the equivalent warming effect of more than 7 gigatons of carbon dioxide, roughly the same global impact as the transportation industry. Nearly 40% of that is produced during digestion: cattle, goats, and sheep belch and pass methane, a highly potent, albeit relatively short-lived, greenhouse gas.

If the reductions achieved in the UC Davis study could be applied across the worldwide livestock industry, it would eliminate nearly 2 gigatons of those emissions annually—about a quarter of United States’ total climate pollution each year.

Ermias Kebreab, an animal science professor at UC Davis who leads the work, is preparing to undertake a more ambitious study in the months ahead, evaluating whether smaller amounts of a more potent form of seaweed can cut methane emissions even further. Meanwhile, some businesses have begun to explore what could be the harder challenge: growing it on a massive scale.

“Very, very high reductions”

The problem is the digestive process of cattle and other ruminants, known as enteric fermentation. Microbes in their digestive tracts break down and extract energy from the carbohydrates in fibrous grasses. But the same process also generates hydrogen, which a separate set of microorganisms feed on, producing methane.

About 95% of the gas escapes through the mouth and nostrils, while the rest exits in the other direction.

Researchers have explored a number of potential paths to lowering livestock emissions, including selective breeding (some animals are less gaseous than others), vaccines, microbiome transfers, various dietary supplements, and more efficient feeds—all with varying results, says Dan Blaustein-Rejto, senior agriculture analyst with the Breakthrough Institute, a research center focusing on technological solutions to environmental problems.

But there’s growing momentum behind the seaweed approach, thanks to almost shockingly effective results in initial scientific studies. In 2014, Australian researchers found that low doses of a red algae known as Asparagopsis taxiformis virtually eliminated methane production in lab experiments. Field trials with live sheep cut emissions as much as 80%, while the UC Davis experiment, the first on live cattle, showed a 58% reduction on average when a related seaweed made up 1% of their diet.

More milk and meat

Kebreab grew up in Eritrea, an East African country on the coast of the Red Sea that struggles with recurrent droughts and famines. The continual shortage of milk or meat inspired him to study livestock, in the hope of finding sustainable ways to produce more of both.

UC Davis professor Ermias Kebreab hand-feeds a cow on campus. Jame Temple


Kebreab first began researching the methane problem more than a decade ago. But the recent work on seaweed was prompted, in part, by California’s passage of a law in 2016 that called for reducing the state’s methane emissions by 40%. That’s placed real pressure on businesses to find effective and affordable ways of doing so, particularly among the Central Valley’s cattle and dairy farmers. The statute focuses primarily on the related but smaller problem of reducing methane from livestock manure—for which there are some available means to make and measure progress. But cutting emissions from cow burps would also count toward meeting that mandate.

“As soon as SB-1383 came online, the interest level increased hugely—and it’s concentrated in California,” Kebreab says.

One negative side effect in the initial UC Davis study is that the cattle did decrease the amount they were consuming each day. That’s a big deal, since the more the cows eat, the more milk or meat they produce. Kebreab suspects the issue was simply taste: seaweed is very salty. The researchers ultimately mixed it with molasses to help the medicine go down.

But crucially, in the initial study, they used a form of seaweed that’s not as potent as the red algae employed in the initial Australian lab experiments. Kebreab intends to use that strain in the follow-up trial, and he believes it could cut more emissions even at a lower dose.

In the months ahead, Kebreab will oversee a six-month experiment with 24 beef cattle. He plans to closely evaluate whether the effect on methane persists at the same level over a longer time period, as well as whether the supplement affects health, weight, and the quality of the meat.

Theoretically, as long as cattle don’t notice the taste (or get used to it), the seaweed should help them put on weight. Blocking methane production should mean that more of the consumed carbohydrates get directed to the task of building tissue. If so, farmers could see an economic return on the up-front cost of this supplement—though it may or may not be the most cost-effective option for packing on weight.

But there’s another concern: how to get the 200 kilograms of red seaweed they need for the study. It has yet to be produced on a commercial scale, and doing so could prove tricky.

Getting to scale

Australis Aquaculture, a producer of ocean-farmed Asian sea bass based in Greenfield, Massachusetts, is attempting to find a way through a research project in Vietnam, dubbed Greener Grazing.

The red algae grows naturally in the wild, but it will take a heavy human hand to produce it at the speed and scale necessary to serve even a fraction of the global livestock industry. And so far, the seaweed has resisted attempts to get it to reproduce, says Josh Goldman, the company’s founder.

Huynh Thi Khanh at work in Greener Grazing’s seed bank. Greener Grazing


Greener Grazing and its collaborators are pursuing several paths to solve the problem. If they crack it, the company will move to the next step of attempting to grow seaweed off the coast of Vietnam. The plants would be placed within the type of plastic tube netting used to grow oysters, and suspended a few feet underwater—just deep enough to be protected from waves, but close enough to the sun for photosynthesis to drive growth.

Meanwhile, DSM, the giant Dutch conglomerate, is working on a synthetic additive for the cows. A paper its researchers coauthored found that a methane inhibitor known as 3-nitrooxypropanol, or 3NOP, cut emissions by 30% in lactating Holsteins. The study noted that milk production wasn’t affected during the 12-week experiment, and as a bonus, the “spared methane energy” helped generate tissue, resulting in higher body weights.

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November 28, 2018 8:43 pm

Darn, there goes my career as a bovine flatulence monitor.

November 28, 2018 8:49 pm

Cows should be left alone to burp in peace and should not be pestered by CAGW fanatics. Cows do not have or seek that exciting a life that they need constant molestation from morons.

Robert of Texas
November 28, 2018 8:51 pm

Just plug the cows into hoses and collect the faltulence… I can see a new generation of Flatulence-Friendly Vehicles pulling up to be re-gassed. Start this new technology in California of course. Here in Texas, we beleive that cows have a gawd given right to pass gas naturally.

Kevin McNeill
November 28, 2018 9:04 pm

I believe ti’s mostly bull shit or there abouts

michael hart
November 28, 2018 10:35 pm

“…several of these Holstein dairy cows participated in a study to test a promising path to reducing methane emissions from livestock, a huge source of the greenhouse gases driving climate change….”

Repeating myself from somewhere else recently…
I regard the methane and cows story as possibly the most ridiculous assertion from the global-warmers. And that is going some. The basic biochemistry of anaerobic fermentation/decomposition of cellulosic materials produces methane. To claim that a handful of (human maintained) ruminants near the top of the food chain emit comparable amounts of methane as the base of the photosynthetic food chain, is to invert a pyramid and balance it on its point.
It just doesn’t stand up. At all. Ever.

The only reasonable explanation for the persistence of this myth is probably the influence of vegetarians and vegans within the crazy community.

November 29, 2018 12:36 am

Methane ruminant prodution being reduced by feed tactics does have potential to be beneficial fo the animals growth. A basic dynamic should be understood beyond the fact that ruminants’ microbial consortia are what convert their feed into volatile fatty acids (& protein) for the animal to exist/grow non.

In the rumen synthesis by microbes of the volatile fatty acid acetate roduces 2 CO2 moles + 4 H2 moles per 1 glucose mole fermented. Then 4 H2 moles in the methane generating reaction aling with 1 CO2 mole forms a methane CH4 mole. In other words 1 glucose mole fermented to acetate for the animal also spins off 1 methan CH4 + 1 CO2 mole.

As for the volatile fatty acid butyrate, for every 1 glucose mole fermented to it (butyrate) there is 0.5 methane CH4 mole + 1.5 CO2 mole also formed. The volatile fatty acid propionate being made is through a different paradigm however.

Rumen propionate formatio does not lead to any CO2 increase & uses H2 in such a way that it
reduces amount of methane CH4 made. In simple terms, when the rumen makes more propionate then more of the energy derived from fermented feed carbohydrate is getting to the animal to use.

This is the scientific basis for attempts to reduce ruminant methane CH4 production that has been co-opted by climate change modellers. Ideally many WUWT readers can see this as of commercial interest.

Now, attempts to force feed proponate to ruminants have revealed there are nuanced issues of the ruminant micro-organisms’ interplay; since excess popionate in feed reduces the animals’ intake affecting growth rate & any milk will have lower % fat.

Original post infered their metane reducing seaweed supplement was rejected by cows for it’s taste. Quite possibly it is related to the seaweeds impact on rate (transitory ratio) of pyruvate formation.

The other methane reducer mentioned (there are others trialed sucessfully) is a molecule (3-nitro-oxy-propanol) that out competes (binds) to a key enzyme that gets methane
production underway. This leaves a lot less of H2 from carbohydrate fermntation by rumen microbes combining with rumen CO2 to form CH4 methane; thus the role of H2 plays out better
for propionate formation.

So, why does cited seaweed cut rumen methane but reduce feed & yet molcule 3-nitro-oxy-propanol in feed result in weight gain? If my supposition is correct that both divert H2 to knock down CH4 methane formation then I presume their actions differ in how their impact affect levels of H2 & microbial interplay (ex: more free H2 favors more Prevotella).

November 29, 2018 1:37 am

What about wild cattle? What about other bovines?
Does this mean any wild animal that farts will have to be shot, to save the planet?

November 29, 2018 3:47 am

“Seaweed could make cows burp less methane and cut their carbon hoofprint.”

Shouldn’t that be methane hoofprint?

The entire idea is barking mad.

Alan Tomalty
November 29, 2018 6:26 am

Did anybody ask the cows whether they like the taste of seaweed?

November 29, 2018 8:27 am

How do they measure cattle flatuence/burping?

Judy Cross
November 29, 2018 12:35 pm

Cows love seaweed. I kept cattle on a island where the cows would go down to the beach to eat it. It produced fat glossy cows. I though it was just the iodine they were after, although they always had an iodized salt block available..

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