RE:RE:RE:RE:RE:RE:RE:RE:RE:Atlas Salt Hey Crunchy get your facts right eh! This from NASA: Which is a bigger methane source: cow belching or cow farting Contrary to common belief, its cow belching due to enteric fermentation. However, a small percentage of methane is also produced in the cows large intestine and then expelled as farts. Settling ponds and lagoons for processing manure also produce copious amounts of this greenhouse gas.