when I see a belly like that, my first question is- what are you feeding? the belly looks like an malnorished baby(bloated stomach) as you've seen rescue groups on tv for. He needs more and the 'right' nutrition. I saw 6+ horses at the last show look like this and then I saw what they were feeding. ugh. Start from the beginning and go from there. one little medicine isnt going to cure him and let a vet look at him, could be something else going on in there too. But you need to change your feeding program. when I got Jr( my yearling) he looked horrible, pot belly, ugly dull coat. So for example- Twice a day- my yearling is getting one cup dry beet pulp(soaked), 2 cups crimped oats, 6 oz alfalfa cubes, 1/4 cup Enrich 32, daily wormer, 6cc body builder and a handful of loose nice grass hay.. he is a bit chunky at the moment, but he has a 13 hr drive to World in a couple days and he will drop about 10 lbs during the trip.
I just had to say this, I think when I was scanning down, I saw you said you were using Omolene? then build him up to- use 2-3 cups Omolene , 1/4 cup Enrich 32, 2 cups crimped, rolled oats.(just a runned over oat). 6-8 oz alfalfa hay or better yet cubes, you can weigh them. and start with a cup of beet pulp and move him up to 1 1/2 cups beet pulp measured dry, but soak it. do this gradual change in about 5-7 days, write it down so you know what the schedule looks like and get him on a daily wormer, it looks expensive at first, but a healthy horse is a happy horse and a lot less trips to the vet. Another thing, people will say - well this isnt a show horse- so then what, you are supoose to feed them crap, do attorneys and doctors eat different high quality foods than a blue collar worker, NO, we all must eat healthy, no matter what you do.
Once you get him where he needs to be, you will see what needs to be cut back from there, but better to have a little chunky than malnourished. Good Luck
