Mashing washes away most of the good stuff from the grains. Whats left is mostly husk and fibrous stuff...dont think it'd be too tasty. My dog loves spent grain & peanut butter dog biscuits though!!
The husks are really unpallatable. You can make flour out of them if you have a good grinder, though. If you're trying to bake bread with it then you should cut it about 75/25 or so with real flour.