heat tolerance conditioning

["Steph Teeter" <steph@endurance.net>]

I know ... this is not exactly a normal topic for January
discussion! But - I would love to hear some dialogue on conditioning
for heat tolerance. My horse, Khruschev, made the invite list
for the Emirates World Cup - to be held in UAE, March 22. 
(also Darolyn and Albanet? Leo and Orfeo? Rita and Cass?). 
It's going to be quite hot for the race. We'll be shipping to UAE 
one month before the race, so the horses will at least have 3+ 
weeks to acclimate. Meanwhile, we're training in winter desert 
conditions - terrain is ok for riding year-round, but it is quite 
cold right now- rarely above 40 degrees. Probably won't change
a lot between now and late Feb. when we ship.

Questions - any idea how long it actually takes for a physiological
response to heat stress? Surface capillary proliferation? This
horse is fairly large bodied, and heat dissipation is a big concern.
How much conditioning response can I expect? Those of you 
who may have had to deal with this before (Leo?) - are there
any tricks that you felt helped? Training with a polar fleece
blanket?? Clip and blanket heavily at night? Or do I want 
to encourage him to overheat with his heavy winter coat?

Last year I spent 6+ months conditioning for the WEC (hot and
humid conditions) - I felt that we were well prepared. At this
point we're looking at about 8 weeks, 4 of those weeks being
spent in the NW. 

Tom - you probably know the conditions in UAE in March better
than anyone. What can we expect? How can we prepare?

Steph 

(I'm sending this post to both Ridecamp and Horsescience - and
intend to share responses with both. I personally find them
to be very complementary lists for endurance competitors - the
science, and the management/training issues)