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Scientists Want to Feed Cows Seaweed to Stop Them Burping So Much Methane

The average cow belches between 80 and 120 kilos of methane every year. By feeding them seaweed, researchers think we could reduce Australia's greenhouse emissions by 10 percent.

by Gavin Butler
16 August 2019, 7:00am

Image via Pixabay (L) and Flickr user Ria Tan, CC licence 2.0 (R)

This article originally appeared on VICE Australia.

Every time a cow burps, the planet’s greenhouse gas emissions go up. Your average bovine probably emits somewhere between 80 and 120 kilos of methane per year, most of which is from belching. Take all the burps from Australia’s national herd of 26.6 million cows, then, and you’re looking at somewhere around 2.6 billion kilos of methane that the country’s cattle industry is pumping into the atmosphere every 12 months.

That’s a problem, obviously, and it’s one that a team of Australian researchers is trying to address by farming a type of native Queensland seaweed that makes cows burp way less.

Adding a small amount of the puffy pink Asparagopsis seaweed to a cow’s diet was found to reduce the amount of gas that animal produced by as much as 99 percent, according to a study by the CSIRO. Cows produce methane because of microbes in their guts that help them break down plants, generating the gas in the process. And certain chemicals in the Asparagopsis algae appeared to diminish these microbes, the ABC reports.

"When added to cow feed at less than two percent of the dry matter this particular seaweed completely knocks out methane," said Nicholas Paul, Associate Professor from the University of the Sunshine Coast. Nicholas reckons if the algae was mass-farmed on a large enough scale it could reduce Australia’s greenhouse gas emissions by 10 per cent. First, though, cultivators need to find a way of “scaling up” production.

"Up until now people have been collecting the seaweed from nature, so wild harvest,” he said. “We have the demand but we don't have the supply.”

That comes with its own set of challenges, such as figuring out which strains of the seaweed reproduce effectively and what the perfect conditions for growing the crops are—not just in the laboratory but in outdoor aquaculture tanks.

"We want, in the perfect world, the fastest growing species that we can find but also the one that produces most of the active ingredient," said Nicholas. His colleague, project scientist Ana Wegner, echoes that ambition.

"We know the chemical composition of Asparagopsis and we know the chemical compounds,” she said. “So now we want to maximise the concentration of that chemical so we can use less seaweed for the same effect."

Agriculture was responsible for about 16 percent of Australia’s greenhouse gas emissions in 2013, about 66 percent of which was methane from burping and farting livestock.

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