30 May 2011

Methane emissions measured in northern Australia

12:48 pm on 30 May 2011

CSIRO researchers in Australia have used laser technology to discover how much methane gas cows in northern Australia expel each day.

The study involved laser beams, a methane chamber and hundreds of cows.

The ABC reports the scientists found cattle in the north emit 30% less methane than previously thought, which is good news for producers.

Cattle in northern Australia eat tropical grasses. Researchers say these grasses are highly nutritional and may be easier to digest.

Researcher Ed Charmley, who has been measuring flatulence emitted by the Brahman breed for over four years, says the concept is quite simple.

''We put a cow or a steer in a large air-tight container that has a known amount of air coming in one end and we collect the air coming out the other side of the container,'' he said.

''The difference in the concentration of methane tells us how much is being produced by that animal.

''The methane chamber gives us very accurate data but in a very highly controlled condition, where the animal's behaviour is changed.''

But the ABC reports the research changed as the cattle were too tense in the small chamber.

Laser beams and wireless sensors were then installed in a paddock, to measure how much methane was coming from the beasts.

Dr Charmley says the new design does not give the same level of precision.

''We have a group of animals out grazing and we shoot a laser beam across the animal and every time the laser beam hits a methane molecule it registers a hit,'' he said.

''In simple terms we look at the concentration of the methane and convert that into an emission from the herd.''

The study found that emissions worked out to be about 200 grams of methane per day, equivalent to nearly 1.2 tonnes of carbon dioxide per animal each year.

Southern study needed

The ABC reports the agricultural industry is blamed for about 16% of the Australia's annual carbon emissions.

Meat & Livestock Australia says studies now need to be done in southern regions to see if it is particular grasses or inaccurate measuring methods that explain the difference.