Why won't you gain weight?

Okay, so, I've had my tb for about 8 months now, and we are having trouble putting weight on him. He is very ribby, and his topline doesn't look the best either (though we are working on muscleing him up).
Here's what he gets feed-wise:
Morning:
1 flake grass hay
2 quarts beet pulp shreds (soaked)
2-4 pounds (not 100% sure on how much it is) bermuda pellet blend (soaked)
1 pound bran
1 pound purina senior feed

Night:
2 flakes alfalfa hay
4 quarts beet pulp shreds (soaked)
2-4 pounds (again, not 100% sure) bermuda pellet blend (soaked)
1 pound bran
1 pound purina senior feed
2 oz. Cool Calories 100
1 scoop of For a Flex (I think that's how it's spelled...) joint/ hoof supplement
1 capsule hyaluronic acid (a human kind, works better than horsey kinds, he has arthritis)
1 oz. Magnesium (from SmartPak)

I think that's it.... I might have forgotten something as this is off the top of my head, and I don't have the feed directly in front of me.

He hasn't gained much weight, only a little bit. He paces in his stall, but the magnesium is helping with that. We have talked to our farrier about his shoes to rule out any possible pain that could be causing him to not gain weight. He is wormed regularly, we have treated him for sand colic (2 weeks on psyllium, 1 week off, 2 weeks on again, now once a week 1 scoop of psyllium), and we have treated him for ulcers. He is getting his teeth done at the end of august, so I am hoping that will help him gain weight.

His old owner had him for 8 years, and she said that was pretty much the weight he stayed, but my mom and I think he's too thin, so we're determined to get weight on him. I don't have any pictures of his weight, sorry. Just so everybody knows, he isn't grossly thin, just ribby and he really looks like he needs to gain some weight. He has a fairly good appetite as well. Any suggestions as to how to put more weight on him? Thanks to anybody who reads this and helps with suggestions!

TB's unfortunately are notorious for being hard keepers. I struck the jackpot with mine, he gets fat off the sniff of an oat bag, but in general, they're known for being hard to put and keep weight on. Also something to bare in mind, is that TB's generally are on the leaner side anyway. The majority aren't built to look like tanks so tend to have that bit of rib showing.

I would feed him ad lib meadow hay, in a round would be best if you have the facilities to do so, so that he can graze all day if you're paddocks don't have much in the way of grass. When fattening horses up, you should always start from the very basics before you look into buying expensive products and supplements. So starting with a good quality meadow hay, giving him about as much as he'll eat, is a good start.
Lucerne (alfalfa) is great as well, but I would be changing his 2 flakes down to 1 flake, and then add 2 of meadow hay to replace it.
His hard feeds look quite good, I would also suggest adding some oil to it. You can use just about any oil, but I really like sunflower oil as it's fantastic for their coat! You can feed up to 250mL (1 cup) a day, but build it up over a period of 1-2 weeks. Oil is a fantastic source of calories, it contains more in 250mL than many of the commercially produced hard feeds have in 1kg.

I don't know how much pasture he has access to, but you might try free choice grass hay where he can eat as much hay as he likes.

Good Luck. I think Rookie is going to be a hard keeper. He's picked up weight and has started evening out as far as his muscle is concerned with daily work. My farrier told me that he could still stand to gain between 100 and 200 pounds. But the saddlebred I used to have was getting 5 gallons of soaked mixed feed twice a day with both flakes and free choice hay. He stayed thin.

I also forgot to add, that if you're really serious about picking his weight up, you can get your vet to give him a blood test to determine what he is lacking. Then you can construct his diet around the results, so you can be sure he is getting everything that he needs.

I agree with free choice hay. I would also have your vet check his teeth and do a fecal egg count to check for parasites.

What kind of bran is he getting? If it's wheat bran, stop. It's not good for them and doesn't help, with anything. If it's rice bran, consider switching to flax meal. I have had better luck using flax to put on weight than rice bran. Feed 1-2 cups a day for weight gain.

Nix the senior feed. You're not giving him enough to make any difference to his nutrition.

Why are you giving magnesium?

Nix the cool calories. It's just dehydrated vegetable fat. It really doesn't do much.

To his diet I would add GrandVite and a digestive aid like Ultra-Elite Digest or SmartDigest (from SmartPak). You want his gut functioning well so he is able to absorb all of the food you're giving him.

I would also recommend as much turnout time as possible, in a large area, if you can. Turnout is good for his mental well being, which will reduce stress and allow him to gain weight better.

So, if he were mine, this is what I would give him:

Morning:
3 flakes grass hay (in small mesh hay nets)
2 quarts beet pulp shreds (soaked)
2 pounds bermuda pellet blend (soaked)
1 cup Flax Meal

Night:
2 flakes alfalfa hay
1 flake of grass hay (in a small mesh hay net)
4 quarts beet pulp shreds (soaked)
2 pounds bermuda pellet blend (soaked)
1 cup Flax Meal
1 scoop of For a Flex
1 capsule hyaluronic acid
1 scoop of Ultra-Elite Digest
1 scoop of GrandVite

TB's are definitely one of the harder horses to put weight on, but not to say it's impossible, it just means deeper pockets. Judging by your feeding regiment I would say you could at least double it. We feed our stock horses that are up to weight more than that a day.

Your horse isnt getting enough hay. He should have access to it all day, a grassy field being best. If you can't do that, try taking him to graze by hand for an hour every day, followed by more hay.

I have had the same exact issue with my OTTB that retired from racing in march. He is just now gaining weight in a noticeable way, and looks great!

Does your horse crib? Pacing that you mentioned is a commone OTTB trait, but so is cribbing. I put a miracle coller on him last week, and he has gained weight already! Basically, he decided "if I can't crib, I guess I'll eat" He didnt used to finish his hay, now he does and wants more. Its quiet amazing actually.

I also give him a scoop every day of FAT CAT, which promotes weight gain. To develop muscle, lots of walking up and down slopes, and on uneven terrain to get his back end working.

Good luck, and Kayty is right: TBs are leaner by nature anyway.

The others are correct- a horse needs grass or hay available to them all the time. A horse gut does not work like our own. It constantly moves and grain just bogs it down and causes problems.

Up his hay intake if you can't turn him out to pasture. You can also feed him chopped hay and/or alfalfa cubes. Cubes will last longer and give himsomething to occupy himself with. He should be getting at least 1/4 to 1/2 bay of hay a day.

You can put him on a senior feed, that is easier to digest and/or also put him on a probiotic that will hlep him digest his feed better so he gets better use of it all.

Teeth are a BIG thing. But not the only thing.

Also instead of feeding that entire amount to him 2x a day try breaking it into 3 or 4 meals. That will help a lot as well. Keeps that gut moving too.

Best luck.

Thanks for all of the responses and suggestions!

Luvs2ride- he gets the senior feed mostly for "flavor". He won't eat his beet pulp without it *sigh* he just has to make things difficult. He is also getting rice bran, not wheat bran. I'll look into getting GrandVite, that seems like it would be helpful. We are giving a magnesium supplement because it's supposed to help "calm him down" or relax him enough not to pace, well in theory

SaratogaTB- he does not crib, thankfully. But man he really paces a lot!

Also, this is pretty much to everyone, with his grass hay, any more than 1 flake or so and he won't eat it. He'll eat the first flake, and just leave the rest. He gets turnout practically every day.
Our schedule is weird for turnout, this is how it works:
Big pasture
Dirt
Little Pasture
Stall
Big pasture
Dirt
Little pasture
Stall
Etc, etc, etc

So he really is out a lot. He's out a lot more than he used to be with his old owner that is.

Sorry, but I cracked up as soon as I saw the title. Figure it had to be a TB. Hay is the key. The more the merrier. So you don't drive yourself completely nuts, evaluate your horse's weight from an overall standpoint. If his butt is round, he had a nice layer of fat on his back and he's overall round with just those pesky ribs showing, you're in good shape. TB's are like marathon runners. They are very fit, but look like anorexics. I've had my OTTB for 3 years now and have tried everything under the sun. To this day those ribs only disappear completely when there's a fat winter coat over them.