A cow sticks its tongue out while being fed at a feedlot in Santa Lucia, some 200 km (124 miles) northeast of Buenos Aires, in this November 13, 2008 file photo. Argentine scientists have found a way ... more 
A cow sticks its tongue out while being fed at a feedlot in Santa Lucia, some 200 km (124 miles) northeast of Buenos Aires, in this November 13, 2008 file photo. Argentine scientists have found a way to transform the gas created by the bovine digestive system into fuel, an innovation that could curb greenhouse gases that cause global warming. Using a system of valves and pumps, the experimental technique developed by Argentina's National Institute of Agricultural Technology (INTA) channels the digestive gases from bovine stomach cavities through a tube and into a tank. Each head of cattle emits between 250 and 300 litres of pure methane a day, enough energy to keep a refrigerator running for 24 hours. REUTERS/Marcos Brindicci/Files (ARGENTINA - Tags: ANIMALS ENERGY ENVIRONMENT SCIENCE TECHNOLOGY) less 
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Reuters | Photo By MARCOS BRINDICCI / REUTERS
Mon, Oct 21, 2013 1:55 AM EDT