I've had good luck feeding another Purina product, called Strategy. It
has a higher fat content than most, puts weight on a horse without all
the sugary carbos in sweet feed, and is well liked by both my horses. My
21 year old app who is still doing 50-milers has eaten both senior and
strategy, and I now feed only the strategy. It is pelleted, and there is
no waste. Senior looks & smells more like a sweet feed, & I'd guess it
might not help calm your horse down at all. Good luck.
Patty