http://blogs.guardian.co.uk/environment/2008/07/bovine_burps.html
Can bovine burp research slow global warming?
Methane, produced by cows, is a more potent global warming gas than carbon dioxide. Photograph: Reuters
Scientists trying to find a solution to reducing the levels of methane in the Earth's atmosphere are using a handful of lucky Argentinian cows in a novel experiment involving bovine burps.
In a country famed for its cattle herds, scientists have strapped plastic tanks to the backs of cows in order to collect their belches and study their methane levels.
The scientists, from the National Institute of Agricultural Technology, say that as much as 30% of Argentina's greenhouse gas emissions could come from cows, and hope this study will find a way to cut down on emissions by changing the diet and lifestyle of the animals.
The grass that cows eat is hard to digest and broken down by bacteria in the animal's four stomachs. In the absence of oxygen, the bacteria turn it into methane. Contrary to common belief, most gas emerges from the front, not rear, ends of the cows.
Farmed ruminant animals are thought to be responsible for up to a quarter of "man-made" methane emissions, which researchers say is 23 times more potent than carbon dioxide when it comes to trapping heat in the atmosphere.
Scientists are working to develop new diets for cows that could make it easier for them to digest food, moving them away from grains to plants like alfalfa and clover.
A study last year found that the average dairy cow in the UK belches out about 100 to 200 litres of methane each day. Given that Argentina is one of the world's biggest beef producers, with some 55 million heads of cattle grazing on the famed Pampas grasslands, that adds up to a significant number.
"When we got the first results, we were surprised. Thirty percent of Argentina's [total greenhouse] emissions could be generated by cows," said Guillermo Berra, a researcher working on the project.
Berra said the researchers "never thought" that a cow weighing 550kg (1,210lb) could produce 800 to 1,000 litres (28 to 35 cubic feet) of emissions each day.
At least 10 cows are being studied, Berra said, including some in a corral whose burps are collected in yellow balloons hanging from the roof.
"We have done a preliminary study and have found that by using tannins, you can reduce methane emissions by 25%," said Silvia Valtorta of the National Council of Scientific and Technical Investigations.
