Well this is very interesting.
My Arab will be 25 April 1st. I rescued him as a starving horse poster child with an injured vertebra when he was 7 and frankly I wasn't sure he'd make it a few years much less 18 years.
I said that to say I have always blamed his issues on the fact that he was starved so bad but, maybe I shouldn't.
The vet was just out to draw blood on him and my 23 yo TWH who is insulin resistant.
The vet palpated my Arab and found him to be "slighltly sensitive" over his right kidney. When the blood results came back, his liver and kidney enzymes were in perfect order.
The vet then said he wasn't sure why Streeter would be sensitive but it could be his life long issues with the injured vertebra. That didn't make sense because the little fella has been seeing a chiro/acupuncturist, as-needed, since I've owned him.
I have worried about cancer, especially since I lost an Arab/Saddlebred to cancer when the horse was 29.
Streeter, my current Arab, developed ulcer issues about six years ago and without fail I have to put him on Ranitidine, long about December. Liquid Omeprazole works fantastic but I have to pay $150 for a 30 day supply and I just can't afford that with all the expense I put into my other horse that is IR.
I recently added timothy/alfalfa cubes to his diet. I soak them into mush that is just ugly but he loves the stuff. I measure one dry pound twice daily and soak it in hot water for half hour before I give it to him.
It "seems" to have enabled me to take him off the Ranitidine of which he was getting (20) 150 mg people tabs daily with the vets approval.
Life is a contradiction in my pasture because this fella needs the green grass to come on but two of my other horses are insulin resistant and can't have much grass. The fourth horse is the only one that's normal, unless I drag his mental state into the pot
I am curious what blood line the OP's Arab is? Streeter was sired by Backstreet and has several crosses to both Raffles and Raseyn.
Your plight sounds so similar that I have to wonder about the gene pool.
Streeter has always been very low on muscle yet he is a hardy fella at 13.3H. He has healthy, oversized, size 1 hooves that I wish were on my Walking Horses.
His eyes are bright and he remains ever-the-trickster and 2nd in command in my herd of four. His little elder self still does not have a problem bossing two of the big Walking Horses around.
The vet is telling me not to worry as long as he is eating, drinking and recycling in the same manner he always has.
Easy for him to say, so I am interested in whatever thoughts, comments are posted on this thread. EDITED TO ADD:
None of my horses have been fed grain since the 23 yo became insulin resistant nearly four years ago. Everyone gets pelleted rice bran, Omega-3 Horseshine, EquiPride vit/min supplement with a pre-probiotic in it.
The Arab also has four molars missing so gets coastal bermuda in his stall and picks the "flufflies" from the mixed grass hay that I throw out in the morning; although he prefers to search grass of which there isn't much this time of year.