Cattle produce several liters of the greenhouse gas methane every day, and they're not known for their ability to control their burps and farts.  When you consider that there's upwards of 1.5 billion of these animals on earth, those emissions really add up.  Researchers looking to cut down on methane emissions from cows have found a promising method in adding seaweed to cattle feed.

CSIRO researchers in northern Queensland found that adding a small amount of dried seaweed to a cow's diet can reduce the amount of methane a cow produces by up to 99 per cent.

"We started with 20 species and we very quickly narrowed that down to one really stand out species of red seaweed," said Aquaculture Professor Rocky De Nys of James Cook University in Townsville, to the ABC.  It's called called asparagopsis taxiformis, and they collect it off the coast of  Queensland.  

"We have results already with whole sheep; we know that if asparagopsis is fed to sheep at 2 per cent of their diet, they produce between 50 and 70 percent less methane over a 72-day period continuously, so there is already a well-established precedent," said Professor De Nys.  Tests with cattle are underway at the CSIRO Lansdown facility near Townsville, and they'll run through the middle of next year.  "We will feed animals and measure more carefully how the seaweed affects both the production of methane and any increase in weight gain in those animals," he said.

This might represent a new business opportunity in Australia.  Wild harvesting the red seaweed isn't a very sustainable idea, but growing it is a distinct possibility.  Southeast Asia already has a booming seaweed farming industry.  Maybe Australia should do it as well.

A 2006 United Nations Food and Agricultural Organization report said the world's livestock sector - most of which are cows - "generates more greenhouse gas emissions as measured in CO2 equivalent (18 percent) than transport."