Join Date: May 2009
Location: Mid Northern TN
So long as you're not making a radical diet change quickly, there is no harm in a nice mash, especially if you're not including a ton of grains/quickly digestible starches. Some bran, some beet pulp, all the hay pellets they want, etc are not an issue. I follow with the line of thought that it's probably not necessary, but if it makes you happy and it makes your horse happy, then you're golden and keep it up!
My boy LOVES mashes. Dryish, mushy, soupy, no matter what is in it he doesn't care- if it is a mash, he hoovers it up. Lately with the cold snap here and their winter coats not grown in yet, I've been giving him a couple (measured dry) pounds each of beet pulp and alfalfa pellets soaked in a 5gal bucket each evening. At endurance rides, he gets whatever he wants (which is any mash with anything in it, see above) and has never turned up his nose at bran or soaked complete feeds either.
The only 'danger' I can think of is that if you soak it too far ahead of time and leave it somewhere warm, it might go rancid, but in the cool, even that is fairly unlikely.