Re: Re: hydration

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

> Okay, so what if (have you missed me asking you questions?)..........

Desperately.  My life has no meaning without it, though I do get a lot more
work done. <vbg>


>
> ...........you go past a questionable water source and your horse insists
> on drinking and you can't stop him?  I've encountered > opinionated about
that.  So what are the risks involved with a horse
> drinking bad or contaminated water, will they really drink something that
> is going to kill them?  btw, a  horse that drank from that
one trough did
> colic.

Well, there you go.  Whether or not they'll drink 'bad' water depends on
just how thirsty they are, what the 'bad' thing is, and the experience of
the horse.  There are plenty of reports of livestock herds being driven for
several days across dry range and then the drovers being unable to keep them
from alkali water that then killed them.  It's kinda the same thing as for
toxic plants---the likelihood a horse will eat a poisonous plant goes up in
direct proportion to what else is available to eat (though that's not always
true).  Also, while some 'bad' things make the water taste bad, others
don't.  Some toxins are of course alot more toxic than others, and its
concentration in the water, plus the amount of water drunk (in other words,
the total dose) will all make a difference.  There are all kinds of factors
like that that would decide whether or not a particular drink of water will
make a horse sick.  No easy answers there.


> I have another question.  ).   So how quickly will
> the quantity and frequency of the horse urinating be affected by
> dehydration?

Depends on how close you're watching.  The body pays pretty damn close
attention to that sort of thing and is constantly adjusting hormone
response, vasodilation/constriction, electrolyte retention and so on to
maintain homeostasis.  So at the cellular level, the response isn't instant,
but pretty close.  How the urine output is going to be affected depends on
the severity of changes, what other toxins (such as ammonia/urea, etc) need
to be excreted, the availability of electrolytes, acid-base balance,
yadayadayada.  I know, this isn't giving you a satisfactory answer (because
knowing you, you want , "within 15 minutes")<g>, but it's just not a simple
concept.  Fluid/electrolyte balance in the body is one of the most complex
systems going on.

> Is darker yellow urine better than none at all?

Well, "none at all" kinda implies some sort of blockage, like urinary
calculi, which isn't likely.  Dark yellow urine means the horse is
dehydrated to one extent or another, but the kidneys are responding
appropriately by concentrating the urine and conserving water.  Which is a
good sign that the kidney is functioning but also means the horse needs to
be rehydrated.  Tons and tons of no-color urine in a horse that you know
*should* be concentrating his urine to one extent or another implies total
renal failure (in other words, the kidneys have lost their ability to
concentrate and retain water).  Dark, dark urine (ie, peeing coffee) usually
means there's myoglobin in the urine, and that implies both muscle damage
and nephron damage.  I remember hearing about a rider who had just ridden a
very hard ride, the horse was peeing almost black and when concern was
expressed, the comment was 'yeah, but he just had a drink, so he's fine.'
HE'S NOT FINE AND BLACK URINE IS NOT FINE.  If there's one concept I wish I
could get across to every rider in no uncertain terms, it's that just
because the horse has crossed the finish line and is still standing upright
the next morning does not guarentee that no damage has been sustained,
whether to tendons, ligaments, muscle, kidney, whatever.


 Have you
> found any correlation in hydration levels versus experience levels in the
> horses your testing?

No, I still haven't gotten back the lab results from Tevis, but I doubt
there'll be a strong correlation between experience and hydration.  Part of
the problem is that there's so much variation in what constitutes experience
 in both horses and riders.

Susan G