Max is 8 years old and has had diarrhea off and on for about 2 months now. Lately its been more on than off. His manure for the most part looks normal but there will be a pile or two that looks like a cow patty. Also, he is a paint and is mostly white and every day for about the past 2 weeks I've had to scrub his behind to get the stains off his butt and legs. He is out on pasture with about 8 other horses every other day and is stalled at night, he eats 2 times a day (morning and night), there have been no changes to his diet, he's been on the same food for about 2 years. He's also on a regular worming schedule. I'm at a loss! I just gave him a 5 day wormer power pack and hope that it will help the cause, today was the 5th and last day of that. For supplements he gets flax seed, electrolytes and biotin in powdered form. Someone at the barn recommended UGuard so I'm probably going to give that a try next. Does anyone have any other suggestions?