Join Date: Jun 2012
Location: Boulder, colorado
Honestly, without the consulting a vet anything anyone suggests is likely to be a shot in the dark. The best thing to do for underweight horses is just free choice feed. Pumping horses full of high cal stuff usually comes with a lot of sugar too.
I wouldn't waste a ton of money on supplements that promise everything and the kitchen sink it's 9/10 times just flash in the pan.
I'm very sure that a competent vet would be able to tell you how well your horse has faired given his poor previous situation. I would say it really depends on how long/when he was starved, and if his dam was starving when he was being developed... I know you said it was a long time but, I would say the most important time for the foal is when it's developing in the dam and if she's being at least fed you have a much better chance in these situation. That's not to say she could be emaciated and foal a perfectly healthy foal but, the odds are just against it more, IMO.
I believe a long time ago I read a peer reviewed article on the benefits of adding glucosamine to a horses diet even in the younger ages being beneficial. I would start researching there and maybe have a chat with your vet because if I were in your situation I would be most worried about early onset of arthritis/osteoporosis.
life has no remote control hitch them up and drive them your self