I am going to disagree - regardless of breed, you should never see ribs. You should beable to feel them, but not see them.
Here is Nelson. In the middle of your Eventing season. No ribs.
Here is Nelson now. He lost over 100lbs at the previous barn we were at due to ignorant care. I wish I caught it earlier, but at the time I had obtained a new job where I was working 80 hours per pay period, and barely had time to get out to the barn. When I did get out there...I saw a horse loosing weight. When brought up with the BO, I got excuses and I gave explicit instructions, in belief that it would change, but it never did.
So I packed him up, and headed out. He has gained quite a bit, but he still has 100ishlbs to go.
You should NOT see ribs!
I have a lot of work to do to get that topline back, but it'll come. Right now, he's out on pasture 24/7, with access to a round bale at all times. And is being brought in 3x a day to be fed 4lbs per feeding, plus shaved beat pulp, cocosoya and his supplements.
All from smartpak
- SmartDigest Ultra
- Magnesium 3,000
- B-L Solution Pellets
- Vitamin E and Selenium
The SmartDigest is for his digestive tract, being 22 he needs it. And the rest is for his muscle development.
So, no ribs should show. Here is my best friends TB. They are doing Training Level this year and doing very well as a matter of fact. Do you see ribs? Nope. Because they shouldn't be there.
Here is my other best friend's 17 year old TB...no ribs....
Get him started on that TC Senior, plenty, plenty, plenty of hay, add some cocosoya and a digestive aid supplement. Go from there. If no weight is gained, then I would look into getting him scoped and assessed.
Start with 6lbs a day. 3lbs per feeding.