Carbo's again-long, sorry

[RALSTON@AESOP.RUTGERS.EDU]

On June 26 you wrote to both me and ridecamp:

>Just had this discussion with Gary Potter.

Very knowlegeable researcher, who focuses on YOUR type of horse:racing and 
anaerobic work like cutting....

> Our conversation was focused on what Gary was calling the hindgut and >
foregut.

Antiquated terminology and very inprecise.....primary used for ruminants.
 Horses are not cows-nor are they humans, though they have digestive 
similarities to both. Their stomachs are unique in that:
   1. they are very small relative both to the size of the animal and other 
	species.
   2. Little if any digestion normally occurs in the stomach.
   3. With abnormal retention of feed in the stomach, as stated before, 
	abnormal production of gas can occur.
   4. There is normally no avenue for release of excessive gas or feed from 
	the stomach: horses can not vomit, most do not "burp" (though both my 
	mare and her dam gurgle like camels when excited!-there's an exception 
	to every rule!)-ergo the risk of painful distension with large amounts 
	of grain. Hay and grass are not as fermentable and do not pose the same 
	risk in a tired, stressed horse...plus they can eat them as fast as 
	grains so the danger of overload is less.

> Within 15 minutes of feeding
>carbohydrate, blood glucose begins to rise. In one to two hours blood glucose
>peaks and begins to recede. How far does carbohydrate move in 1 1/2 hours?

Absolutely true.  It only takes three lbs of grain (just about any type will 
do) or 1 gm glucose/kg body weight (about .4 kg or 1 lb for average size horse) 
to get this effect. The peak is higher if the horse has been fasted overnight 
and lower if hay is offered concurrently or the horse not fasted. Glucose/
insulin metabolism and the effects of diet there upon is what my research has 
focussed upon for the past 5 years (no-not all of it 5 year old data, ti, the 
most recent data is "hot off the press"-ie: still being analyzed-science is 
continuous, not static). Based on work by Argenzio and Hintz (among others), 
fluids and small particles empty from the stomach within 10 to 15 min-ergo the 
rapid increase in glucose (stimulating insulin) after your carbo doses or 
grain. The stomach of a horse is completely empty within 1 hour of a meal of 
pellets or grain, whereas under normal grazing or free access to hay their 
stomachs are never completely empty. The "empty" equine stomach continues to 
secrete acid, since it was not designed to be empty-increasing the risk of 
stomach ulcers. Recent research reported that merely taking horses off pasture 
and confining them to stalls for a week, regardless of diet, increased the 
incidence of ulcers...so stress has something to do with it too. Another recent 
report revealed that over 50% of the TB racehorses at the track had gastric 
ulcers, a rare finding in our distance horses....

>probably should have said "pre-large intestine", which is Heidi's focus, and
>is where carbohydrate digestion can be a disaster--this, again, according to
>Potter.  

	Yes, excess soluble carbohydrate reaching the cecum and large colons in 
horses causes abnormal fermentation, which at best reduces the efficiency of 
digestion, and at worse, when occurring in a horse not adapted to high carbo 
rations, causes bacterial die off, endotoxin release, colic, laminitis and even 
death. As little as 3 lbs cornstarch (ie: pure carbo source) reliably causes 
laminitis and colitis X  when given a a single dose-in fact it is used as a 
model in laminitis (founder) research. 
	It is of importance to note that in the average size horse (1000 lbs) 
fed more than 4-5 lbs of concentrate (grain or pelleted feed)per meal has 
significant bypass of the high carbo feed into the cecum and large intestine. 
Your racehorses are adapted to this, having received the high amounts of grain 
practically since birth (ergo the inefficiency noted by, I think, Joe). 
However, this is why I recommend feeding a maximum of 4 lbs per meal and also 
making any increases slowly over the course of several days. It's amazing what 
horses can adapt to if given a chance...
 
>Until you have actually attempted a better feeding protocol, please restrict
>your comments to the 30 year old literature. Otherwise, you'll inflame the
>very few innovators we have out there on the front lines. This thread began
>with a half a dozen of them sharing their clearly positive experiences with
>techniques that do not appear in the equine literature as of yet. 

Yes, and I commented that based on a clearer description of what they were 
doing versus what you had previously given us to understand, I said I had no 
problem with the people dosing their horses with the carbos during the ride 
(more about that later). You keep implying my information is out of date. 
First, we are all constantly and on a daily basis, learning more about the 
physiology and metabolism of this remarkable animal, and this is good. Many of 
the studies upon which I base my comments are as recent as 1998, some as old as 
1965. The bulk of the good stuff on exercise physiology in horses has been 
published in the past 10 years, with the increased availability of high speed 
treadmills. But that does not mean the 1965 work on basic digestion and glucose 
metabolism is invalid!! The basic anatomy and physiologic/metabolic principles 
do not change!! Glucose is absorbed from the small intestine-and nothing your 
innovators can do will get the stomach to do this trick! Please do not confuse 
innovation with ignorance. Many of your previous statements have revealed a 
rather appalling lack of understanding of basic horse nutrition (though some 
very interesting theories and some that are rightfully being tested).

>By the way, I've spent a little time with endurance folks, been to a few
>endurance rides, a couple of ride and ties, touched a few of the creatures,
>helped haul a couple of exhausted ones away. I've helped design workout
>gameplans for several winners. I'm not completely out of touch with the >
sport.

You could have fooled me....

>My living, though, is derived principally from racing. In comparing the two
>sports,  I find racing to be far more competitive

Yes, because there are $$$ involved and you and many others DO make a living 
off it. I am unaware of anyone making a living off riding endurance horses!! 
(Though we do contribute greatly to the livelihood of people like Teddy and 
Roger who keep us supplied with all sorts of goodies :-)

>with far more innovation
>taking place. To a lesser degree, eventing is also more competitive and
>innovative. 

I beg to strongly disagree here- it was the ENDURANCE riders that convinced the 
3-day eventers they should maybe pay attention to heart rate recovery (which 
you apparently don't have to worry about in race horses) and who pioneered the 
use of fat in the ration of hard working horses (before Dr. Potter even thought 
of it!). No one else has picked up on the cardiac recovery index (thank you, 
Kerry!!). There's innovation occurring in every sport-usually in the area where 
the greatest emphasis is placed: in racehorses it's getting them to go the 
fastest, hopefully without breaking down in front of the sqeamish fans-so track 
design and ergogenic diets are foremost on the innovation front. In 3 day 
eventing, heat exhaustion was a real concern, as were the metabolic deficits 
accumulated over the grueling three days, so a lot of work has been done on 
cooling and replacing water and electrolyte losses (which has also benefitted 
our endurance horses, though we already "knew" a lot of what was found in the 3 
day research-gee whiz, folks, horses that sweat a lot need electrolytes!!! 
surprise, surprise).
In endurance, it's keeping a horse healthy and sound for 12-24 hours of 
continuous work, with the well-being of the animal paramount (not always the 
case in the other two). Totally different emphasis and areas of innovation.
yes we have our share of "hot shoes" but they represent a minority of the total 
population of competitors. If you find our sport so boring why bother with us?

>That's not to say that there is no innovation in endurance--it's just that
>there are more folks interested in defending the past than looking toward the
>future.

Who? Most of us who are disagreeing with some of your theories and 
recommendations are not doing it out of fear of innovation, but out of sound 
knowledge of the physiologic and metabolic capabilities and disabilities of our 
horses!!

BTW: With respect to endurance horses being "underfed" and those following your 
"innovative and daring" recommendations being the only ones who are properly 
nourishing their horses:
        Endurance horses can require up to 30 Mcal per day, depending on size, 
rider weight and terrain, etc. For the average 1000 lb horse with normal 
digestive capabilities, this can be readily met by 20-25 lbs of good quality 
hay (1 Mcal/lb) and 4-5 lbs of grain (1.3 Mcal/lb for low fat, 1.5 or more for 
high fat). Your innovators are giving 2 ounces of straight carbo paste (0.004 
Mcal/gram at best, 30 gm/ounce so a max of 0.24 Mcal per 2 ounce dose). Even if 
they did this every 2 hours for 12 hours (as some reported) you are talking 
about an added 0.72 Mcal-less than 1 lb of hay!!! Which is why I don't worry 
about them doing it-if it confers some sort of magical benefit, more power to 
them-I may even try it myself! But at least I am confident it won't hurt 
them......

	In my over 20 years of experience, working with both TB and 
Standardbred trainers, 3 day eventers and drivers, endurance and competitive 
riders among a few (NJ is a great state with regard to wide variety of 
horses!!), the most informed AND innovative are the distance riders and 
Standardbred trainers.
 
Whew-guess this what happens when you go on sabbatical-you get long winded and 
combative! Nuff said.

Sarah Ralston, VMD, PhD, dACVN

and Fling (My "guinea pig" on whom I test all my own theories and a few of the 
others-ie: my electrolyte recipe needed molasses plus I ruined two blenders 
before figuring out all I needed to do was add 1/8 cup molasses, water and 
shake-duh!! Rescue Remedy does not work if she has already seen the trailer 
door open (sorry Roger), Pennfield's new endurance feed looks really good on 
paper but finicky Fling hated it, etc etc.)