Just looking for information as I have been wondering if it could be her diet. I know it's hotter than blazes here in Florida with high humidity. She is on a COB mix made at the local mill that the other 5 horses in the barn eat. She is usually sweaty when she comes in to the stall during the day and sweats way more than the other horses during excersice. I'm thinking maybe of switching her to a low startch/sugar diet with no corn, looking back last year when she was on Ultium and at the trainers on her pelleted diet she did not sweat like this. Anyone have diet make them sweat more?

My mare is a major sweater. She is hot in every way. None of the other guys are sweating; she is. They all eat the same thing. It's not my feed. When you're standing next to this mare, you can feel the heat coming off her. She sweats at rest. When you're riding her, the breastcollar gets soaked. You can't use it twice. She gets full of lather and drips. She happens to be a nervous mare and has ulcers. The vet told me they lose a lot of magnesium, which is calming, when they sweat. Could have something to do with her nervousness. I think, like people, she's just hotter. I'm cold all the time. My friend is hot all the time. I rub her down with Epsom salt baths after riding. The vet told me to use the Epsom salt. I think there is magnesium in it? I don't think there is anything I can do to stop her from sweating. I hose her a lot, keep a fan on her in the stall, and have many saddle pads and breastcollars to use. As an aside, I don't know if your mare is nervous and/or has uclers, but I give her U-Gard, red raspberry leaves, aloe vera juice for her tummy, and ViaCalm to prevent the nervousness. 

I'll take one that sweats too much over one who doesnt sweat enough ANY day.  I would make sure you supplement with electrolytes to help. 

I do supplement with electrolytes and she always has a salt lick. I agree also, about having one that sweats too much rather than not enough.

Have one like that. The ONLY thing that helps is BioStar’s Cool something. I can’t remember the whole name. He still sweats, but not as much and if you use it consistently, you can start to feed it every other day or so. I am in South Texas,so high heat and humidity is just a given year round. Every one said don’t worry he is sweating, but he was miserable, you could tell it stressed him and affected his attitude. Normally, I wouldn’t have worried about it, BUT with high humidity I know his sweat was baking him. I mean, they do tell us to immediately scrape the water off your horse when you hose them down. I know it’s after a workout, but he was just as sweaty and hot as a normal horse that was just worked, sooo.....long story short the BioStar stuff worked.