I'm doing some research for my wife who takes care of our her horses. Two of our 10 yo geldings are big & cresty (brothers from a different mother). No lipoma or abnormal fatty deposition, just cresty necks. The other 3 geldings and 2 mares are unaffected. They all get fed the same - IIRC already a low-ish carb horse feed. Both are just fantastic auto pilot cow horses.

She showed me one of her throwaway rags that had some supplements for cresty necked horses. Someone else said to get the special Nutrena feed for them or go straight oats. Anyone have any experience with those supplements or feed choices for cresty necks.

Low Carb is what you want. The lower Carbs you can feed them and keep them happy, the better. You can get a blood test to see if the are Insulin Resistant or not, which means a real Problem or not. Many Cresty as you described are just fine and will live healthy forever. Some are not. I have one that is "not." He will founder on too good of green Grass hay and nothing else. He fell off the Insulin Resistant wagon at about 10 years old. Never had a real problem, that displayed in negative health effects, before but his DNA was there from birth of course.
http://ecirhorse.org/ for some reading.

Interesting...

Yep. Like all things Horse, this one little problem has wide foundations in DNA. I, like you Ray, have been a horseman all of my life. I had never heard of the term, "Insulin Resistant" until just a few years ago. Lot's of testing over years built up a body of science that any local vet can pull blood, send it off and tell you the probability of this horse continuing to have the same problem he just had. My vet said after looking at the blood report, was amazed my gelding made it as long as he did without presenting founder before. I am still keeping him going on Prairie hay and a little luck along with frequent trimming his bare feet. I could turn him out on the green spring grass for two hours and founder him though.

I do know you can sweat them off with a rap, slow but sure process combined with proper diet and exercise, just like people.

I have found that early green pasture is deadly for horses, unless you start them slowly..Actually anytime you change diet it should be a slow process..From winter alfalfa to pasture is an hour of pasture a day and alfalfa to balance the grass, but I let my pasture grow to a foot high to start the change. Seems to work for me, but a horse that has seriously colic'd once tends to repeat himself it seems. the operation works sometimes but its incredibly expensive..

The best thing in the world for keeping a horse sound is wet saddle blankets, and that's much easier in the high desert country we have than in the hot humid climes in parts of the south and the size of our pasture gives your horse a 10 mile ride on an easy day. Its definitely a blessing.

Yes I have sweated quite a few show horses to make them look better, but it doesn't change the metabolism on the inside. Diet, Exercise as you mention, I am keeping one alive and somewhat useful that way, and the outcome is dependent on the DNA the horse was born with and how it has modified his metabolism.
Best regards Ray.

My competition team roping horses are old and they been in the roping arena most of their lift, they older they get the better, but they must be managed properly, cared for on diet and exercise and some added vitimins etc don't hurt as well as medications to keep them going..Young horses are a pain the a$$ they have issues that must be delt with everytime you rope. Some girl is still roping off my old horse Mojo at the Bendiolo arena (SP ?)f in Boise Idaho and he is 25 years old, and going strong. My present horses are 17 and 18.