I think this is about the most sure thing if you are going to make a blanket statement. A TMR should improve herd health and reduce feed cost, or else increase production. I focus on health-my motto is ,"feed 'em to keep 'em healthy and let 'em milk what they want". Still maintain a 21-22K herd average feeding 10 lbs of grain mix/cow/day.

Like anything else, the machine is not magic, you have to manage it properly.