Why feeding seaweed to cows is good for the planet

Diane Godley 22 June 2022

A new kind of cattle feed could cut methane emissions drastically and make cattle farming more sustainable in the process

Some 15 years ago, in the picturesque Canadian province of Prince Edward Island, an organic farmer from the aptly named area of Seacow Pond split his dairy cows across two paddocks, one of which had beach frontage.

Over time, Joe Dorgan noticed that his cows by the ocean were in better shape than their fellow bovines. They were producing more milk, had fewer udder infections (so, health costs decreased by one-third), and were highly reproductive. They seemed to be all-around happier animals.

The only difference he could see between the two herds was that the more content ones had access to the beach and were eating seaweed.

On a hunch, Dorgan dragged seaweed across the road for his land-locked cattle to see if it would make a difference. Before long, those bovines were catching up with their seaside chums.

So he sold his farm to start a new enterprise, North Atlantic Organics, selling organic sea plant products to local farmers.

He knew he was on to something big. But he had no idea that what he had noticed about his cows’ new diet was about to give the world a potentially significant weapon in the fight against climate change.

Cutting greenhouse gases

In time, Dorgan learned that although he could feed his own cattle seaweed and even give it away, he needed approval from the Canadian Food Inspection Agency before he could sell it commercially.

To get the agency’s go-ahead, he required data, so he approached two agriculture scientists at Dalhousie University in the neighbouring province of Nova Scotia. Their focus was on animal nutrition and alternative feed additives to enhance productivity and environmental sustainability.

"One cow can emit the same amount of greenhouse gas as one car"

One of the scientists, Rob Kinley, was also researching ways to reduce greenhouse emissions in livestock by tinkering with their diet.

For cattle to digest grass, they need microbes in their guts to help break down the cellulose. And it is these microbes that release copious amounts of global-warming methane.

On average, one cow can emit the same amount of greenhouse gas as one car. Approximately 15 per cent of global greenhouse gases are made up of methane from livestock.

With Dorgan’s seaweed mix in hand, Kinley started measuring emissions from the cows. What he discovered was an 18 per cent reduction in methane emissions compared with non-seaweed-eating cattle.

It was a lightbulb moment, and a global search for an even more efficient seaweed began.

A little seaweed goes a long way

A cow in CSIRO's  research centre enjoys her seaweed-supplemented feedCourtesy of CSRO. A cow in CSIRO's research centre enjoys her seaweed-supplemented feed

By 2013, Kinley was en route to Australia via the Netherlands, where he was working with probiotics and feed inoculations.

In Australia, he contacted colleagues at the Commonwealth Scientific and Industrial Research Organisation (CSIRO) and James Cook University who specialised in seaweed and livestock, and they began screening seaweeds off the coast of Queensland state.

But they weren’t just randomly choosing the seaweeds.

“We knew what the chemistry of the seaweeds needed to be, and we knew what potential impact certain things could do in the rumen [stomach] of cattle, so we selected the seaweed based on their bioactive contents and chemistries,” says Kinley.

Taking their top seaweed candidates, they started reducing the amounts in the cattle feed until it got to about five per cent. “We virtually lost the effect of nearly all of them, except for one,” says Kinley.

It was the red seaweed, Asparagopsis taxiformis. Results were so dramatic that Kinley thought the lab equipment was faulty. However, retesting confirmed that supplementation as low as just 0.5 per cent of the total feed mix yielded roughly 80 per cent less methane.

"If just ten per cent of the world’s farmers used seaweed, it would have the equivalent effect of taking 100 million cars off the road"

With escalating global greenhouse gas emissions and increased pressure to manage climate change, Kinley powered on to try to achieve even better results.

By the time he and his co-authors published the feedlot study “Mitigating the Carbon Footprint and Improving Productivity of Ruminant Livestock Agriculture Using a Red Seaweed” in the Journal of Cleaner Production in 2020, they had the seaweed supplementation down to 0.2 per cent and were eliminating 98 per cent of methane.

With those kinds of numbers, if just ten per cent of the world’s farmers used the seaweed ingredient it would have the equivalent effect of taking approximately 100 million cars off the road.

That would give governments that are inflexible on climate policy no reason to leave agriculture out of their 2050 zero-emissions targets.

Methane emissions stay in the atmosphere for around nine years,
a shorter period than carbon dioxide (CO2), but it has a global-warming potential 86 times greater when averaged over 20 years.

Removing the methane that cattle produce means the animals can become carbon negative—contributing to an overall reduction in greenhouse gases.

Another positive result? Milk or meat output is higher, because when the methane that cattle emit is reduced or eliminated, they are able to increase the fatty acids produced in their bodies.

As a result, beef cattle could grow faster, says Kinley. They could produce the same amount of meat with much less feed, or, the ultimate goal, produce more meat with less feed.

The growing aquaculture industry

The potential for the seaweed supplement to reduce the world’s greenhouse gas output is massive, and the hope is that cattle will be consuming FutureFeed—the commercial product developed by CSIRO, Meat and Livestock Australia, and James Cook University—by the end of 2022.

But first, large amounts of cultivated seaweed are needed—a new industry and a secondary benefit of the “super weed.”

When FutureFeed was awarded the Food Planet prize from a pool of more than 600 entries in late 2020, judges noted the product’s other positive impacts, stating: “The technology could have indirect benefits including filtering detrimental nutrients in ocean water and creating alternative incomes in developing countries where fisheries are in decline.”

"The technology could filter detrimental nutrients in ocean water"

FutureFeed is already working with several industry growers, including First Nations groups in Queensland, to propagate the seaweed on a large scale. But startups are surfacing all over the planet, including in the United States, here in the United Kingdom, and Sweden.

Others are dipping their toes in the water, says Kinley, and with many aquaculture businesses such as oyster and mussel farms decimated by disease, some are looking to make the switch to growing seaweed since they already have the infrastructure in place.

Initially, FutureFeed will only be able to reach beef and dairy cattle in feedlots (as opposed to grazing cattle). When you take into consideration that dairy cows eat around three times as much as beef cattle, “That’s a lot of emissions,” says Kinley.

The supplement could start rolling out in Australia, Europe, and the United States by the end of this year.

And because the micronutrients in the seaweed would replace some of the expensive additives traditionally put into the feed to provide a balanced diet, costs should be reduced. According to Kinley, with efficiencies in processing, the price will drop as time goes by.

More seaweed means less CO2

Red seaweed growing in tank copright CSIROCourtesy of CSIRO. Seaweed is also good at filtering CO2, so more aquaculture could help stabilise our oceans' acidity

As the Food Planet judges pointed out, another environmental benefit of growing seaweed is that it cleans ocean water.

Seaweed, like all photosynthetic plants, gobbles up CO2, which is responsible for the proliferation of ocean acidity that softens calcium-based shells and corals.

The gas is found in runoff from agricultural lands and can cause algal blooms that can be toxic to humans, livestock, and fish. Therefore, seaweed grown on a large scale will act as a biofilter and turn pollution into clean ocean water.

According to a 2016 study published in Nature Geoscience, seaweeds could sequester an estimated 173 million tonnes of carbon each year, which is approximately equal to the annual emissions of the state of New York.

Of seaweed’s potential, says Kinley, “there’s a long chain of wins with this.”

Read more: Swimwear made from ocean plastics – What you need to know

Read more: Could you live a carbon neutral life?

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