Hi Dr.O
When I say « the vets » I mean the university hospital vets (which is what I think you refer to as equine internist… sorry my english is not so good!). There is one team on the road for clients in a close range. It’s been a while that my local vet referred this case to them!
The test was ACTH but the filly has no symptoms whatsoever and we were not surprised by the negative result. The insulin test is baseline insulin and was 3,6.
At this point the equine specialist says that we could do eventually peritoneal fluid analysis or a laparoscopy to explore the fatty tissues, or a muscle biopsy. However they think these tests won’t reveal much in terms of knowing « why » she is like this or give any possibility of treatment. They also mentioned the paracenthesis would be difficult because there is so much fat everywhere the needle wouldn’t be long enough. So for now they said to keep up with the diet and try to do a little more exercice but they don’t think it will help much.
Since they have no clue what is going on, and especially that the filly is doing very well despite her weird shape (she has good energy, interacts normally, no pain anywhere on the body, good coat and hooves etc) it doesn’t match any known disease. As for the thyroid test I asked and they said the result interprétation is not reliable?