Mane care

Question
I have a Spanish Mustang gelding that foundered a few years ago on grass. He used to have a long thick  mane. I have pretty much got the founder under control but since I have been keeping him off the grass in the spring and summer months his mane has disappeared. It is only about an inch high off his neck. I know he might  be rubbing it out because of boredom. Is there anything else you can suggest for me? I sure would like to see him get his mane back like it was.  

Answer
There are supplements you can add to his feed that are good for the coat and mane or you can just add 1/2 cup of corn oil to his grain once a day (or a 1/4 cup twice a day).  There is also a product called M.T.G that can be purchased at Tractor Supply Company (or most equine health/food stores).  It doesn't smell great, but it is super for growing manes and tails.  If you think he is rubbing (which is not likely if the whole mane is the same length, try a "sleezy" or "mane tamer" a lycra hood that protects the mane from rubbing or other horses chewing on it.

I tend to think that it is dietary or fungal though, so try an additive and the M.T.G and see what happens.