Horse weight loss.

Question
Mr. Wolfson,
I own a 9-10 yr old sorrow gelding quarterhorse.  Over the past several months he has been loosing weight.  I took him to our local vet who checked his teeth and floated them again.  This was previously done one year prior.  In addition to the teeth float we wormed him and provided feed for sand.  This horse eats like a turkey-gobble, gobble, gobble.  We have increased his feed to two good flakes of hay about twice a day, the usual is one flake in the am and one in the pm.  In addition we feed corn and rice bran.  We re-wormed him again, yet his rib and hip bones are showing.  From his shoulders down he looks like an old nag.  Shoulders and up like a fine horse.  When he eats he works his way through the food contiously eating, hardly any stopping to chew, corn or other feed, he does not drool or backwash portions of his feed and once he starts hardly comes up for air.  I would appreciate your assistance on this matter since I am very concerned that the problem is much bigger than worms or the like.  Thank you,
Carl  

Answer
This horse is looking to eat about 25 lbs of feed total a day. If you are only giving about 10 lbs of hay,  he is hungry. You would be better off giving him as much hay as he wants and cut the feed down.
It is hard to tell how much grain to give him, as I do not know how much work he is doing.
You can also try adding some beet pulp to his ration.