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Feeding cows small amounts of seaweed could reduce their methane emission by more than 80 per cent © Breanna Roque/UC Davis

Feeding cows seaweed could reduce their methane emissions by more than 80 per cent

Published: 17th March, 2021 at 18:00
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The effect can be achieved using just small amounts of seaweed and makes no difference to the flavour of the resulting meat.

Everyday, a single cow can burp out hundreds of litres of methane – a potent greenhouse gas. As there are more than one billion head of cattle in the world, this means cows kept for dairy or meat are making a significant contribution to climate change.


For this reason, many experts say we should all be reducing our meat consumption. Now, researchers at the University of California, Davis have discovered an alternative that could mean meat lovers can still enjoy their beloved burgers.

They found that mixing in small amount of the seaweed Asparagopsis taxiformis can reduce the methane in bovine belches by 82 per cent by inhibiting enzymes in the cows’ digestive systems.

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"We now have sound evidence that seaweed in cattle diet is effective at reducing greenhouse gases and that the efficacy does not diminish over time," said UC Davis’ Prof Ermias Kebreab, Sesnon Endowed Chair of the Department of Animal Science and director of the World Food Center.

“Only a tiny fraction of the Earth is fit for crop production. Much more land is suitable only for grazing, so livestock plays a vital role in feeding the 10 billion people who will soon inhabit the planet. Since much of livestock's methane emissions come from the animal itself, nutrition plays a big role in finding solutions.”

The team added about 80 grams of the seaweed to the daily diets of 21 beef cattle over the course of five months. They found that these animals gained the same amount of weight as their herd mates but burped out far less methane.


Results from a taste-test panel found no differences in the flavour of the beef from seaweed-fed steers compared with a control group of animals fed on standard feed.

Reader Q&A: What are cows communicating when they moo?

Asked by: Dileep Bagnall, Lancashire

Old MacDonald had a farm with an ‘oink oink’ here and a ‘moo moo’ there, but we’d be foolish to think that these vocalisations have no significance. Cows are smart, social animals. They have a rich repertoire of communication that includes moos, grunts, bellows and even non-verbal signals such as tail position.

In 2014, researchers at the University of Nottingham and Queen Mary University of London decided to delve a little deeper by recording 10 months’ worth of moos and then using computer analysis to look for patterns. Just as our voices differ, the researchers found that each mother and calf have their own individual call. This is thought to help them identify each other in a herd.

The researchers could also tell a calf’s age by the sound of its call. Meanwhile, mother cows produce two different maternal calls: a low-pitched moo when they are close to their calves, and a louder, higher-pitched moo when they are separated from their calves, or just before nursing. Calves, in return, make a different call when they are separated from their mother and/or want to suckle.

Of course, this is just the tip of the iceberg. Ask any farmer and they will tell you that cows ‘talk’, not just to each other, but also to those who care for them. Cows moo when they are hungry or stressed. They moo as a warning and they moo in anticipation, if, for example, the farmer is approaching with a big bale of delicious hay.

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Jason Goodyer
Jason GoodyerCommissioning editor, BBC Science Focus

Jason is the commissioning editor for BBC Science Focus. He holds an MSc in physics and was named Section Editor of the Year by the British Society of Magazine Editors in 2019. He has been reporting on science and technology for more than a decade. During this time, he's walked the tunnels of the Large Hadron Collider, watched Stephen Hawking deliver his Reith Lecture on Black Holes and reported on everything from simulation universes to dancing cockatoos. He looks after the magazine’s and website’s news sections and makes regular appearances on the Science Focus Podcast.


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