Well, different vets have different approaches to this, but from experience, if you’re not testing, you don’t know what’s up and you don’t know what you’re treating.
My horse is coming 24. Since about the age of 13, I suspected Cushings or another metabolic issue. Hairy, air fern, fat pockets, cresty, delayed healing, prone to soft tissue problems, etc. I had him on the diet and exercise regimen of a Cushings horse and had bloodwork for thyroid, Cushings, insulin, leptin, and the other normal suspects run annually. He tested within normal range for everything until the age of 15, at which point his leptin levels were just above normal. On the basis of his previous bloodwork this was an evident spike and we started treating that. Leptin went down, overall body condition improved. At 18 his ACTH tested just a point or two outside normal range for the time of year, but, again, it showed a change from the previous 5 years of results and justified starting treatment. And finally 2 months ago his thyroid levels showed up out of whack and finally justified treating that. If I’d put him on Pergolide at 15 it wouldn’t have helped his leptin. If I’d put him on Thyro-L at 18 it wouldn’t have helped his Cushings. The fact that I had annual results from year to year helped to identify the clinical significance of relatively small changes and come up with a treatment plan that supported what was going on inside his body.
I’m not suggesting that you don’t know your horse. You know your horse well enough to know something’s not right and to have a good sense of what it might be. But you don’t know for certain the problem you’re trying to solve, which does mean you’re doing a bit of throwing stuff at the wall to see what sticks and introducing prescription medications that have potentially adverse side effects.
