Ridecamp: Re: [RC] RC: Vetting procedures

> Hey Susan -- do you know, or did you survey the riders to see what they
> thought about the condition of their horse?

You mean, after finishing a 100 mile ride?  Good Lord, it would have been
more than my life was worth to ask the riders to do anything other than head
for bed at that point.  I was thrilled we got them to let us pull blood and
weigh the horses one last time.

> >While there were some horses that completed Tevis with abnormal lab
values,
> >it goes more towards arguing that some conventional lab values may not
> >necessarily apply to endurance horses (ie, CK values).
>
> Ya think? <g>

You'd be surprised at the numbers of vets that still think elevated CKs
alone during or right after sustained exercise still equates invariably to
muscle damage.  Which it doesn't, necessarily.

> When you get a chance, (ha ha, I know....sorry), have you any suggestions
> on what we can do to avoid 'cumulative damage'?

Yeah.  Speaking metabolically...

1) Don't override the horse.
2) Keep him hydrated and know what hydrated means.
3) Feed him small, frequent and appropriate meals throughout the ride.
4)  If your horse is peeing coffee, go get help from the vet and for god's
sake, don't think, "he just needs a drink and then he'll be fine", or "he
always does that, so he's fine".

Tough, huh?

  Is there any way to
> measure that kind of damage?

IMO, the kind of damage we're talking about is renal (kidney) damage.  You
can assess it quite well via a biochemical profile and urinalysis.  You can
also do a kidney needle biopsy, but that's highly invasive and totally
inappropriate for field research.  The problem is that it was tough enough
getting serial blood samples from 40-50 horses throughout a 100-mile ride.
It's *really* unlikely I could convince riders to carry a urine sample cup
with them on the trail and leap off to catch some when the horse decided to
pee.  Having enough research volunteers to follow around horses at every vet
check would be a logistical nightmare.  Running a catheter into the bladder
at vet checks is easy, but I doubt riders would volunteer for that, either
and alot of horses would require sedation, which wouldn't work at a ride.

So when I can figure out logistics, I'll let you know the extent of renal
injury in endurance horses.  I suspect the data will have to be collected
after exercising horses on a treadmill (and there are problems with that,
too), or I'll have to organize a research ride as Jeannie Waldron has done.
All of which will be a lot more likely once I'm back east at Rutger next
year and have much better toys to play with.


 I've got friends who have horses that tie up
> repeatedly, and they just keep on going......are they just lucky to be
> getting away with it, or is it just that the horses are enduring it
without
> really being damaged?

Or, option 3, the horse is tying up repeatedly, accumulating damage and the
horse just hasn't crashed yet (and sallowing for the difference between a
mild muscle cramp, true acute RER and slow-onset-dehydration-related tying
up), .  How many horses have you heard of that raced at incredible levels
for a season or two, peed coffee on a regular basis but the owner never
noticed or changed anything because the horse was still completing, and then
crashed at an easy 50 and either died or spent the next week on fluids
before being "retired"?


> Also, do you know how weight loss compared to the bloodwork---any ideas on
> how much weight a horse should be able to lose safely on a 100?

Geez, I've have to look up data at home to give you numbers and I'm at the
VTH.  However, if memory serves, we collected data on horses that lost from
0 to almost 100 lbs over a 100 mile course, and finished in good shape,
biochemically and to outward vet inspection.  The average weight loss was
around 60 lbs, I think, or about 6% of bodyweight, and that coincides with a
lot of other published data.  In our case, I can't remember if that
correlated strongly to biochemical indicators of dehydration or
not---certainly a lot of the weight loss was water loss, but not all of it.
Glycogen, adipose tissue and dry matter gut fill would contribute as well,
and that's hard to quantify.

 I think you could make a reasonable estimate that 90% of weight loss during
a ride is water loss, and based on that, I would *personally* be looking for
signs of dehydration and problems if weight loss exceeded 60 lbs in a
1000-lb horse.  That would equate to 5% dehydration, about the point where
cellular function is adversely affected (actually, that occurs around 3-4%)
and outward signs of dehydration are becoming apparent.

However, there is also some good data around from various sources, mine and
others, that horses that lose the majority of their total weight loss in the
first 20-30 miles are less likely to finish than horses that lose weight
slowly and consistently throughout the ride (which is supported by our
findings that horses tend to be MOST dehydrated between the 25 and 50 mile
mark, and then rehydrate themselves later in the ride).  That finding of
early pulls is undoubtedly an indication of the horse's ability to eat and
drink early and throughout the ride, water losses through sweat, normal
feces, abnormal losses resulting from stress(ie, stress diarrhea, nervous
sweating, etc) and things like that.

 For
> example, if you are at a ride that has a scale and you know your horse has
> lost a certain % of body weight you'd be wise not to continue regardless
of
> whether the vet passes you -- ??

See above.  But, I don't think you can invariably say, 'my horse has lost 60
lbs, so I'm pulling', unless you saw other problems, or the horse didn't
feel right, or unless you knew you're horse never lost an ounce at any other
ride before (like....Weaver <g>).  I would just start paying alot more
attention to eating and drinking if my horse always lost more than 5-6% of
his bodyweight during a ride, or tended to lose most of it during the first
few loops.  I think you need to evaluate each situation individually.  If a
horse had lost an abnormal amount of weight, and it was due to primarily
unreplenished water losses, there will be other concurrent signs of
dehydration that any good vet will pick up.

Susan G



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