Question: I have been feeding my 32 yo Arabian 2 cups of cocosoya per day. for the last 2 weeks.  He had been getting 1 cup from the beginning of June.   He gets 12 lbs of Triple Crown Senior, whatever alfalfa hay he can eat, 1 lb of alfalfa hay cubes, 1 cup of rice bran and 3 oz of ProMana Senior Weight Builder.  He absolutely loves the cocosoya and rice bran.  Hay cubes and Senior Weight Builder not so much.  He has PPID.  Question:  Is 2 cups of the oil too much to give him.  It is what I use to ensure he eats most of the Triple Crown Senior.  He has not gained any weight since starting the CocoSoya.

Dr. Kellon: Triple Crown Senior is already high fat (10%) so adding too much can get you to a point of diminishing returns because too much fat depresses fiber fermentation.  TC Senior is a high fiber, low starch and sugar complete feed so you are not getting the full calorie potential from the feed. That's probably why he's not gaining weight. He may also have chewing issues because even older horses whose teeth look OK have changes in the angle of their chewing surfaces which decreases the efficiency of chewing.

I would suggest stopping the alfalfa, rice bran and ProManna. Get him some timothy or bermuda hay pellets and work up to 9 lbs/day with the CocoSoya 2 cups and 5 to 10 lbs of TC Senior.  Mix all ingredients together and always wet his meals enough to soften pellets and Senior to the point it is falling apart easily. The wetter, the better with  seniors. Also put him on Tri-Amino.

Because of his age he should be checked for Cushing's Disease (PPID). That would cause weight and muscle loss.