Thanks for great information, Baby'sMomma.
Our vet has not recommended blood workup or biposy's.
Diarrhea is his only symptom. Water I use is bottled water no refrigeration. While it's in bowls say during summer it will cool down little bit from a/c in the house but not to "chilled" temperature. I'm good on that point
Our vet is treating it as "inflammatory bowel disease" and not "irritable bowel disease. In reading up there is a difference, I have learned

Diet seems to be the key since all medications have been tried from previous vet and our new vet. He has no plans for further medications. If the venison doesnt work we go back to low residue. There is a good possibitly we are dealing with a food allergy.

Coccidia started this whole mess off.