Hello, my name is***** and I have over 20 years of experience as a veterinarian. I am sorry to hear about your fellow's chronic loose stools, ravenous appetite, and panting.
Hyperactivity is pretty common with high strung shepherds, and may improve with maturity. His personality may be at least in part influencing his loose stools, and adrenaline can lead to hypermotility of the gastrointestinal tract.
Panting can be secondary to nervousness and anxiety, or may be a response to abdominal pain and intestinal cramping, which I would expect with loose stools.
This must be frustrating for both of you.
Is he feeling well otherwise?
Is he gaining weight and growing appropriately, or does he seem much too thin even with eating more than most dogs his age and size?
Do his stools ever look greasy?
I understand that he has had stool samples checked for parasites.
What testing was done to look for EPI? How long has it been since his testing? Sometimes trypsin will rise and fall early on in the disease process, so we can get normal results if he happened to have his testing done at the time when it happened to be in the normal range.
Has he had any other testing done?
I would recommend a stool culture as well as thorough testing for parasites and likely the use of a broad spectrum wormer to start.
Then because he's a shepherd and their prediposition to some particular gastrointestinal problems I would check a complete blood count and biochemistry profile as well as a blood test for pancreatic function called a TLI. This measures the amount of pancreatic digestive enzymes. If not high enough it is a common reason for chronic or intermittent diarrhea. Even it was normal previously if it has been a while since his test and his stools have worsened, especially if he is very thin, it is worth repeating.
Shepherds are also prone to small intestinal bacterial overgrowth so a course of antibiotics for 10 days may be very helpful. I would also recommend probiotics, either Fortiflora, Benebac or Proviable.
Is there ever blood or mucous in his stools?
It is possible that he has food allergies/sensitivities or inflammatory bowel disease.
Checking blood levels of cobamalin and folate can help identify small bowel disease.
If his biochemistry profile and TLI are normal and he doesn't improve with a good worming medication (like Panacur or Fenbendazole) then I would try dietary manipulation.
I would recommend a true hypoallergenic
diet such as Purina Veterinary Diets HA or Hills z/d. He will need to eat this only (no treats
or flavored medication/rawhides/bones
) for at least 8 to 12 weeks to see a full effect.
He may have inflammatory bowel disease, that is definitely worsened by stress, and should respond to dietary manipulation, although sometimes we need to add immunosuppressive drugs too. This is diagnosed with biopsies of the intestinal tract, so if food manipulation isn't enough then the next step would be biopsies.
Best of luck with your fellow, please let me know if you have any further questions.