Probiotics and body temperature

[ChacoL@aol.com]

Three of the nine endurance horses at our barn are chronically underweight,
despite getting the same ration and more or less same workload as the others.

This spring, we started the three underweights on probiotics, choosing
Fastrack at Susan Garlinghouse's suggestion.  The horse I ride is one of the
these three, and I noticed that he has a chronically depressed body
temperature (don't know about the other two).

A trainer I know has a large barn of mostly Arabs and Morgans in training for
western performance.  Two of these horses chronically sweat a little on hot
days just standing in their stalls.  These two horses are hard keepers.

This got me wondering if horses with normally high or low body temperatures
are not able to maintain a good level of gut flora, knowing that bacteria can
be very sensitive to temperatures.

Then I opened the latest KV Vet Supply catalog to order a new supply of
Fastrack, and find it now listed under Livestock, rather than Equine supplies,
and the description says it improves the appetite of cats and dogs as well as
horses!

I thought gut flora were pretty much species-specific.  Is it possible that
the same flora benefit humans (Fastrack contains Lactobacillus acidophilis),
cats, dogs, and horses?  And if so, does this shoot down my body temperature-
gut flora theory?

I would be interested in (1) any comments on why horses might need probiotic
supplementation (why they would be deficient in the first place), and (2) if
anyone has any theories about or experience with the relationship between body
temperature and ability to maintain weight.

BTW, the three horses on Fastrack DID hold their weight better this fall as
the pasture grass depleted.

Thanks for your ideas.

Linda
San Francisco