The most farting producing animals are termites. Next in line are the camels, than the Zebras, the sheep, the cows, the elephants, the dog (Labradors/Retrievers), the humans + Cowpea*.
*Cowpea is one of the most ancient crops known to man. Its origin and subsequent domestication is associated with pearl millet and sorghum in Africa. It is now a broadly adapted and highly variable crop, cultivated around the world primarily for seed, but also as a vegetable (for leafy greens, green pods, fresh shelled green peas, and shelled dried peas), a cover crop and for fodder.