Feeding cows seaweed could save the planet by cutting their greenhouse gas emissions by more than 80 per cent, scientists found - writes Tom Campbell.

Methane is one of the most potent greenhouse gases, trapping 25 times more heat than carbon dioxide.

Every time a cow burps or passes wind, a small amount of methane is released into the atmosphere.

Combined, cattle are responsible for around half of the greenhouse gas emissions produced by livestock, experts said.

Now a type of algae, known as Asparagopsis taxiformis, could be used to tackle this problem after it was found to curb the amount of methane cows’ produce by neutralising enzymes in their digestive system.

While this heightened methane production from cattle has prompted calls to stop the eating of meat, only a small portion of the earth’s surface is suitable for crops.

Now, researchers at the University of California, Davis have come up with a solution, which means people won’t have to give up on burgers.

Study author professor, Ermias Kebreab, said: “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.

“This could help farmers sustainably produce the beef and dairy products we need to feed the world.”

The researchers added “scant amounts” of seaweed to the diet of 21 beef cows over the course of five months.

Four times a day, the cows were fed a snack from an open air contraption, which measured the methane in their breath.

Cows that consumed doses of about three ounces (80 grams) of seaweed gained as much weight as their herd mates but produced 82 per cent less methane, the researchers found.

Professor Kebreab said: “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."

In 2018, the researchers were able to reduce methane emissions from dairy cows by over 50 per cent by adding seaweed to their diet for just two weeks.

How it works is the seaweed inhibits an enzyme in the cow’s digestive system which normally helps produce methane.

A taste-test panel found meat and milk from seaweed fed cows to be just as tasty as those on classic diets.

Adding seaweed to cows troughs could pave the way towards producing meat without damaging the planet.

Scientists are already studying ways of farming the type of seaweed used by the researchers, as there is not enough of it in the wild.

Next the researchers will look at how farmers can feed cattle seaweed supplements on an open range.

Co-author Dr Breanna Roque said: “There is more work to be done, but we are very encouraged by these results.

“We now have a clear answer to the question of whether seaweed supplements can sustainably reduce livestock methane emissions and its long term effectiveness."