Could Blue Chip Karma have zonked my horse?

[joy]

I have used this stuff twice before big occasions.
Firstly before a two day dressage training seminar because he is a youngster and it would have been his first big ridden event and last week before a big show this weekend.
I didn't take him to the show because for three days he could not come out of a walk
Furthermore at the dressage training the trainer said he was lazy.
He's 5yo 7/8tb, home bred and home broken, he's sharp without being nasty so could it have been the Blue Chip Karma if nothing else in his programme either feeding or work has changed?

 

[Silverspring]

Could it maybe be due to the heat recently? I have a rather sharp horse who over the past few weeks has turned into a bit of a donkey, she barely bothered to prick her ears at stuff that would have thrown her into a hissy fit in the cooler weather. I wouldn't expect a feedstuff to have a prolonged effect on his behaviour i.e more than 24 - 48 hours.