Howdy,
Bloat = when you have had them on strictly grass and put them into a pure alfalfa field. You get bloat. Such as they all race in there and eat like crazy. Thier stomachs and bugs are not ready for it and they bloat.
The same thing happens to me during thanksgiving.
I fill my plate and eat like crazy, then later unbuckle my pants and try to stay awake watching a football game.
Get them used to alfalfa and you will not have any problems. Besides, this advice goes for just about any dietary change. Say you have a bull on feed test. (rather hot mixture) you do not just stop cold turkey. you gradually lower the feed intake on the ration.