Albumin is a protein that is free-floating in blood plasma. While it is present any time there is a bleeding injury, albumin may also release itself through smaller injuries that only seep plasma. This manner is consistent with hindgut's  “leaky gut” syndrome. Additionally, albumin digests with the aid of bile and proteolytic enzymes in the small intestine. As a result, albumin present in a horse’s feces is thought to primarily originate from the hindgut.