Re: RE: Another Electrolyte question

["Susan Garlinghouse" <suendavid@worldnet.att.net>]

> Hello,
> I've been trying to follow this thread. I have a question. About someone
>
> saying NOT to give electrolytes if the horse has not had a drink, why?
> Is there a medical reason? Please clarify.
> thanks,
> anna.


When salt hits the stomach, the physiological response of the body is to
immediately dilute it down to a particular tonicity or
concentration---simpler terms, it adds water to it so the body can absorb it
more easily.  The source of that water is from the blood.  So, worst case,
let's say your horse has been sweating really hard, hasn't been drinking at
all, his skin tenting is just awful, his gums are tacky and dry, no doubt
about it that the boy is really dehydrated.  Now you've added salt to the
system and even more water is removed from the blood to go into the stomach.
That bit extra (which actually can be fairly substantial) *can* be enough to
totally push the horse over the edge into a metabolic crash.  So under those
circumstances, adding salt on top of being dehydrated hasn't helped the
horse at all.

OK, second scenario.  Let's take the same really dehydrated horse above that
hasn't had any electrolytes all day.  He's got dried salt crust all over
him, and has been losing electrolytes with the sweat all day.  He finally
decides to stop and really tank up, just drains the buckets dry and hey
presto, he goes over the edge into a metabolic crash *anyway*.  What
happened this time is that alot of water moved from the GI tract into the
blood, but because he's deficient in electrolytes, the blood doesn't have
all the electrolytes needed to maintain cellular function---because where
the word electrolyte came from is just a substance that carries electrical
charge in cells to maintain function.  Too much water, not enough
electrolyte is just as bad as too much electrolyte and not enough water on
board.

So if you ever have a horse that's this dehydrated at a ride, *you* probably
shouldn't do anything except get your butt over to the vet, because
he/she'll have a better handle on what the horse needs to correct the
problem without pushing the horse over the edge.  Alot of the time, that's
when and why they'll start running IV fluids---supplying both water and
e'lytes in the right balance so the horse doesn't fall over.

So, here's what you do to avoid both of the above scenarios.  If you give
electrolytes via syringe in small (ie 1-2 oz) and frequent (every few hours,
depending on the ride, heat and humidity) starting before the start of the
ride and LONG before the horse has had a chance to get depleted in anything,
then that will do two primary things.  1) it's going to get little bits of
e'lytes into the system so the horse doesn't get depleted throughout the
day, and because the doses are small, there's not as much fluid having to be
shuffled into the stomach, plus less upset tummy; and 2) assuming the horse
never gets electrolyte-depleted, then the salt concentrations in the blood
will get just a little higher than normal---that's perfectly normal, and
okay, and what happens is that the slightly higher salt concentration is
going to kick in some pretty complex endocrine responses, one of which
signals the kidneys to filter out the excess salt, and another of which
tells the horse he's thirsty so how 'bout taking a drink.  He's not really
dehydrated at that point, but this is a good way to sortof fool the system
into thinking he is; and to help get a horse to start drinking earlier in
the ride *before* he actually gets so dehydrated that you're running into
one of the two scenarios described above.

I know this is kind of a Romper Room explanation, but Corrine is right,
fluid balance and acid-base is pretty complex and hey, reading ridecamp
shouldn't be like studying for an exam.  Anyway, hope this clarified the
whole when-to-electrolyte-and-when-not-to-and-why-not thing. :-)

Susan G