Cow Dung is a term use for the feces of the bovine species. The species includes the cow, buffalo, ox and bullock. Cow dung is basically the digested residue of herbivorous matter which is acted upon by symbiotic bacteria residing within the animal's rumen. The resultant faecal matter is rich in minerals. Colour ranges from greenish to blackish. In due course, the resulting matter turns yellow due to chemical changes caused by sunlight.