Methane is emitted by animals as a product of enteric fermentation. When food gets digested, microorganisms in animal’s stomach feed on food, helping it to break down, with one of the results of this process being methane. The livestock sector is globally responsible for about 30% of total annual methane emissions, only preceded by fossil fuels. Two-thirds of livestock emissions are attributed to cattle.
From the enteric fermentation, the most methane is produced by cows, buffaloes sheep and goat. Pigs emit low levels of methane connected to enteric fermentation, and poultry does not emit it. However, manure storage serves as a methane source as well, and here, pigs and poultry lead the emissions. Total emissions however are still led by cattle.