With a few exceptions, most animals pass gas, but the frequency and content of that gas widely vary among different species.
Most farts contain hydrogen, carbon dioxide, nitrogen and sulfurous gases (with the latter responsible for much of the smell), but scientists are primarily concerned about another common component, methane, since it is a potent greenhouse gas. Methane has the capacity when in the atmosphere of raising earth's temperature through absorption of long wave radiation.
According to a paper published in the latest issue of the Journal of Experimental Biology, nearly 30 percent of Earth's methane emissions originate from ruminant livestock. Ruminants are mammals that are able to acquire nutrients from plants by fermenting them in a specialized stomach prior to digestion, principally through microbial actions. This process results in a lot of excess gas.
"It's hard to forget the sheer amount of methane that ruminants produce," Iain Brassington, a bioethicist at the University of Manchester, said.
According to the EPA, cows are among the top methane makers. The rumen of a cow (an organ where the microbial fermentation occurs) can hold 40 to 60 gallons of material and an estimated 150 billion microorganisms per teaspoon. Such concentrated fermentation means that cows break wind often, releasing an estimated 551 to over 1,100 pounds of methane per day.
Gassy Cows Emit More Methane than Oil Industry