Cows fed small amount of seaweed burp 86 per cent less methane in trial: A trial where cattle were fed a small portion of seaweed in their diet has reduced their methane emissions by up to 86 per cent. But some scientists warn we need to be careful not to create "another cane toad".

Feeding cattle a small amount of a seaweed species found in Australia has been shown to reduce their methane emissions by up to 86 per cent.

Supplementing either 0.25 per cent or 0.5 per cent of a cow's daily feed with Asparagopsis taxiformis — a red seaweed native to Australian coastal waters — resulted in an average drop in methane production of over 50 per cent & 74 per cent respectively over a 147-day period, according to a study published today in the journal PLOS.

Methane is a potent greenhouse gas that has a warming potential around 25 times that of CO2 over a 100-year period.

Enteric methane emissions — emissions produced in the rumen of livestock — are responsible for as much as 14.5 per cent of the annual greenhouse gases produced by human activity.

The potential to cut emissions from cattle so dramatically could significantly reduce the impact the beef industry has on climate change, according to study lead author & animal science researcher Ermias Kebreab from the University of California.

"There needs to be a few more studies, but we see this as having a huge potential to reduce methane emissions," Professor Kebreab said.

"The cattle that were supplemented with seaweed actually had a better feed conversion efficiency — they gained more weight for the same amount of feed — compared with those that were not supplemented.

"We would say this is a win-win scenario."

Primitive microbes called archaea use the carbon dioxide & hydrogen produced by digestion of food in a cow's gut to produce their own energy.

In doing so, they create methane as a by-product, which is mostly burped out the cow's mouth & not farted out, as...