Carbos and eating crow

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

Hi Christina,

I don't (yet) use carbo loaders myself, so this is only to report what
the potential concerns are from the academic camp on using this
product.  A few other people have commented on getting "flamed" for
using carbos, so I want to make this REALLY clear, I personally have no
problem with carbo products, as a matter of fact I have less problem
with a carbo-loader than I do with feeding alot of grain during an
endurance ride.  So this is all under the category "fully informed
decision" and my word is FAR from being the last word.

As you probably already know, horses use fats and carbos as the primary
fuel sources during exercise.  As the intensity of exercise goes up,
reliance will shift from primarily fats to almost entirely carbos
(sugars) so that at a sprint, you're burning no fats, just sugar.  At
typical endurance speeds, you're burning primarily stored fats, but
still significant amounts of sugars---somewhere around 65-70% fats and
30-35% sugars.

The difference between the two is that while the equine body can store
LOTS of fats, it stores relatively small amounts of sugars.  And
regardless of how much fat you have available, if you run out of sugars,
exercise pretty much stops---this is what they mean when they refer to
glycogen depletion.  It just means your sugar gas tank is empty and
you're done for the day.  Another saying (very true) is that "fat burns
on the flame of glycogen".

So this is the point of carbo products---even though fats remain yur
primary fuel source during endurance, it's sugars that are in lesser
supply so you want to maintain a steady supply so you don't run out.  OK
so far?

So there are two ways you can try to keep your sugar supplies high(er). 
One is try to get more sugar into storage before the event and this is
the "pre-loading" others have referred to.  Some, like Tom Ivers,
advocate this and have reported success.  Other published research
studies have reported that horses already store large amounts of
glycogen (more than humans) and so pre-loading is relatively
ineffective.  In all fairness, these reports used older protocols and
possibly newer products are now more successful at storing more glycogen
in the muscle cell.  The other concern about "pre-loading" (again, with
older protocols) is that in SOME horses, carbo-loading has resulted in
episodes of azoturia, or tying-up.  This hasn't been well-explored in
the research, so it's not like anyone is saying this WILL happen---Tom
Ivers I believe has pre-loaded probably thousands of horses and hasn't
had a problem.  On the other hand, there are alot of factors and
differences between TBs on the racetrack and Arabians doing endurance. 
So, PERSONALLY, I have reservations that there is any great benefit of
using a carbo product over plain old grain to build glycogen stores the
day before a ride. 

The second way of keeping sugar levels high during the endurance ride is
to supplement carbos DURING the ride.  Think of this as starting out
with the same size gas tank,but stopping now and then to dribble in a
bit more gas so you don't run out.  What you're trying to do is keep
blood glucose levels at a steady level throughout the day and thus avoid
fatigue and maximize performance.  Traditionally, people have done this
by feeding grain during a ride, which has some significant problems
attached to it.  Or, more recently as a result of Tom Iver's experiences
and advice (and I will admit, vision), carbo products which more than
likely do not have the same problems associated with them that grains
do.

I posted in the past (about a month ago) the fluid shifts that occur
when a horse is fed relatively large meals---say, a horse that travels
25 miles without a bite, then comes into a vet check and gobbles down
several pounds of mash.  Briefly, this protocol moves a LARGE quantity
of fluids out of the tissues and into the digestive tract for several
hours, thereby creating an artifical metabolic dehydration that can
contribute ALOT to metabolic failure (colic, thumps, heat exhaustion,
tying up, whatever).  In addition, a large intake of carbohydrates
causes a glucose "spike" in the blood levels, followed by a decline.  At
the same time, you get an increase in insulin.  Without getting into a
big diatribe on endocrinology, suffice it to say that while you do get a
relatively short period of higher glucose levels, those levels fall off
rather than stay steady, and fat utilization is depressed.  So you have
a short period of more energy, followed by a period of MUCH less
energy.  Definitely not what you want.

There is another problem associated with feeding large grain meals. 
When all that grain hits the cecum, the pH of the cecum drops
significantly.  The microbial population of the gut is disrupted and
with enough disruption, endotoxins are released by dying microorganisms
and absorbed into the bloodstream, where they can potentially cause
founder, damage to the intestinal mucosa and other problems.  You REALLY
want to avoid this, especially in an endurance horse that is already
under metabolic stress.  This isn't just being alarmist, this is a
Biggie.

OK, here's where the carbo products fit in.  Carbos fed in a syringe at
regular intervals will also help keep the blood glucose levels steady. 
If you fed a whopping dose (I know, unscientific) only once, you'll
probably get the same unwanted spikes you would with grains.  Not good. 
If you dosed with smaller doses (others can tell you what doses they're
feeding) at a regular interval, then you should avoid the spikes and get
a steadier glucose level and avoid the insulin problems---which is
GOOD.  Very good.

Here are the potential concerns from the academic world, and I will be
the first to admit that some researchers are stodgy old
stick-in-the-muds that fanatically shy away from anything new until it's
been researched to death.  (I try not to be one of those if the
arguments and logic are good, which they are in this case).

The concerns are whether carbos will cause the same effects that grain
overload does: 1) will it cause the same fluid shifts?  Although there
has yet to be any research on this (I might be doing it this summer, God
willing), probably not.  Alot of the fluid shifts are the result of
chewing and since carbo products are syringed, there's no chewing
involved, so should be almost zero salivary secretions.  Pancreatic and
bile secretions should also be zero, since just sugars won't stimulate
those like other feeds will.

2) Will carbo products cause a pH drop in the cecum?  Again, probably
not---the majority of the sugars will be absorbed from the small
intestine into the bloodstream and never make it to the cecum.  The tiny
amount that MIGHT make it back there isn't going to cause any major
changes to the microflora, so no worries of endotoxemia and damage to
the mucosa.  Again, this is very, very good.

So here's my take on carbos---I still have doubts that using it before a
race has any particular benefits over plain old grain, but I have no
particular objection, either.  Used during a race, I think you could get
decreased performance if you used it incorrectly (large doses at
infrequent intervals).  Used correctly (relatively small doses at
regular intervals), there certainly seems to be increasing evidence from
reliable source (one rat research or not) that performance is improved.

Whether or not a tummy-sensitive horse would be bothered by carbos, I
don't know.  It might very well be his tummy problems were the result of
grain products and using a carbo-loader would help him, not hurt him. 
Give it a try and pay attention and tell us all what you think.

If know this has gone on a long time, so this is the last Public
Announcement and I hope you're reading this, Tom---over the past few
years, Tom Ivers and I have gone 'round and 'round about the use of
carbo-loaders and had some pretty hot debates over it.  Good points on
both sides over their use, but I admit I relied on opinions from alot of
researchers that refused to try something new and dismissed carbos
without (in my opinion) really thinking them through.  Since then, I've
done ALOT of reading and alot of thinking and re-exploring exactly what
happens where in the digestive gut of the horse and I've changed my
mind.  I think used properly, carbo products may be the niftiest thing
for endurance horses since the saddle, so...Tom, I bow abjectly.  We may
still disagree on a few points, and I still think you're a crotchety 
old curmudgeon, but if you make it to ICEEP in September, drinks and
dinner are on me.  I still want to do and see the numbers this summer,
but now it's more to argue with Rose and Snow, not with you.  How's THAT
for a turnaround? :-D

Christina, I hope this covers in excruciating detail what you wanted to
know about carbos.  Be prepared that SOME vets (from the reports I hear)
may still flame you for using them on your horse.  Listen to your horse,
who'll give you better and truer data, and let us all know how you did.

Susan Garlinghouse, Eater of Crow Pie


Randall Aldridge wrote:
> 
> Hi all,
> 
> After reading all the posts about carbo loading, I'm thinking about trying
> it for my horse at our next ride.  I do have some questions though.  Has
> anyone had any problems with it or any problems using it on a horse w/a
> sensitive digestive system?  Also, our next ride is in July & it will be
> extremely hot & humid (upper 90s & humidity about 80-90%); any problems
> w/carbo loading in extreme temperatures? (It's also a 3 day ride, I'm
> planning on doing 2 days w/day of rest between.)  What dosage would be best
> for hot weather and would it be any different for cold weather? I'd like to
> get all the info I can, good & bad, before I make a decision.
> 
> Thanks in advance,
> 
> Christina & Khali (mare w/an attitude)
> Houston, TX where it's hotter than h---, & if anyone's got rain SEND IT TO
> US!!!