Re: RC: Definitions and a time out

[Tivers@aol.com]

In a message dated 7/27/00 7:29:31 AM Pacific Daylight Time, 
ralston@AESOP.RUTGERS.EDU writes:

<< Ti: all exercising horses are catabolic!>

A sliver of a fine point, but I'll agree.

> When we are talking about feeding these critters, it is important to not 
lose
 sight of the fact that calories are calories. If a horse consumes less
 calories
 than it is burning, it will catabolize (see the definition above) it's body
 fat,
 protein or glycogen stores to meet the energy requirements. >

But there is a cascade of fueling priorities, catabolizing tissue protein is 
at the bottom of the list.

>In a
 non-exercising,
 healthy horse, body fat is the store of choice, with muscle protein and
 glycogen kicking in only
 if the deficit is extreme, if fat breakdown is somehow inhibited (high
 glucose/insulin),
 or in certain disease states. In the exercising horse working aerobically
 both glucose 
 (carbohydrate) and fats are used. The fats come from circulating fatty
 acids from
 the absorption in the gut offats and from body fat breakdown, be it from
 fat stores or triglycerides
 stored in the muscle.>

Again, a cascade here, with stored triglycedrides the much-preferred fuel.

 >Volatile fatty acids, absorbed from the hind gut
 fermentation
 of fiber and any starches that bypassed the small intestine, can also be
 used but are 
 funneled through the same metabolic pathways as glucose, not fat.
 
 If the horse consumes more calories than it is burning, it will store these
 excess calories
 as fat. There is a limit (though the exact limit has not been established)
 to how much
 glycogen and triglycerides can be stored in the muscle-all those carbos ti
 wants 
 to feed don't get converted strictly to glycogen, nor does all the fat
 loading fat
  go to intramuscular triglycerides. The bulk of the excess calories goes to
 fat!>

Remember, I'm not pouring fat into the horse, just providing enough of  it to 
top the tank of IMTGs (intramuscular triglycerides)--still not enamoured of 
carrying much in the way of body fat into an endurance  race. 
 
 >Susan's excellent field survey of the Tevis horses brought to the fore that
 rider weight, within reason, did not, in and of itself, influence the 
 horse's ability to complete the ride. It was a factor. BUT the most
 significant
 correlation between horses that completed versus those that were pulled for
 metabolic fatigue
 was the condition score of the horse, regardless of rider weight, horse
 weight,
 phase of the moon. The Henneke conditioning scoring system has been
 validated to 
 correlate closely with the amount of body fat a horse has-says nothing
 about catabolism,
 anabolism, glycogen stores, or fitness. What is does tell us is the
 relative amount of stored energy the
 horse has under it's skin-not necessarily what it has in it's gut or
 circulation.
 Susan's study showed conclusively that, under the rigorous Tevis condition,
 horses
 that do not have adequate body fat stores to draw upon have a higher risk
 of metabolic
 fatigue and failure. If these skinny, low fat horses were carbo charged
 every hour or so,
 giving them the glucose to run on (need not worry about inhibiting fat
 mobilization here-
 they don't have any to spare!) they probably could do ok. But carbo
 charging is not
 yet an exact science, and if done wrong, can result in hypoglycemia (low
 blood glucose)
 or worse. Our horses are working predominately in the aerobic realm-burning
 both glucose
 and fat. Susan's study emphasized the importance of having those fat
 stores, regardless
 of speed, feeding regimen or training. And I do not mean jiggling pones
 of fat (I believe condition scores of over 7 (considered moderately obese)
 did poorly too, no Susan?), just a nice smooth look-no ribs or hip bones
 jutting out. >

I can go along with that--no fat rolls along the backbone. 
 
 >On a personnal experience note:
 Fling had her best recoveries and performance ever this year, when she was
 carrying a good 50
 to 75 lbs more weight than last year. I had to press her flank a little to
 feel a rib, her loin was flat,
 her neck blended smoothly into her shoulders and her withers had a nice
 padding around them-not round,
 but smooth.>

What do you think would happen if she were carrying 100 to 150 more lbs of 
fat?
 
> Ti's latest "proof" from the human literature concluded with this:
 >Based on this review, a baseline diet comprising 20% protein, 30% CHO and
 30% fat, with the remaining 
 >20% of the calories distributed between CHO and fat based on the intensity 
 >and duration of the sport, is recommended for discussion and future 
research.
 
 Who is going to feed their horse 20% protein? The "low" fat diet in this
 study was 10-15%,
 which is considered high fat in equine rations! Again, horses don't have
 gallbladders,
 are not adapted over evolutionary time to a carnivorous or even omnivorous
 diet as are humans.>

Again, no need for another comarative anatomy course--you're forgetting, 
entirely, the FFAs contributed by forage. 


 >Ounces of weight count in human and horse races where maximum speed is
 being sought. Ti's
 greyhounds with no excess fat have to rely on their carbocharges>


Give me a break! Who's talking about greyhounds? No need to distort my words 
to prove your point--bad debating tactic--you sound like Al Gore.

> and
 hopefully are fast enough to
 get across the finish before they run out of fuel.>

Again, this is your fantasy, what you'd like me to be saying, so that you can 
have an easy target to attack. Why don't you stick with facts instead of 
blundering into false statements to make a point. Both you ladies have this 
bad habit. It's a sign of insecurity.

 >But a well conditioned
 "fatter" horse, 
 even carrying a heavier rider, can do just as well, especially in
 technically difficult 
 rides like the Tevis-Susan's data show this to be true. NONE of this is all
 or none>

Then why are you presenting it as such?

>-thin
 horses have top tenned-even with heavy weight riders, well conditioned
 horses with 
 light riders have crashed. Read Susan's articles in the AERC news, work
 with your horse,
 pay attention to it's weight and attitude and enjoy your rides, whatever
 your goal maybe-to finish
 or to win!>

What a wonderful homily Completely devoid of useful, specific information. 
 
> nuff said.>

Methinks there will be more.
 
 
>Sarah and the pleasantly plump Fling
  >>

ti