Horse lacking that bit of buzz? (Feeding related) (Also in NL and CR!)

[rotters13]

I have a very laidback polish warmblood which is lovely except at competitions when I feel that she is lacking a bit of buzz! Particularly during the xc phase when I feel like I'm working harder then her!

Anyone tried any of the Xtra Boost paste or Propell plus? Anyone else have any other ideas?

Thanks!