RE: [RC] [RC] Glycemic index of horse grains - Susan E. Garlinghouse, D.V.M.
*I’ve been
reading so much lately about grains, glycogen, beet pulp, that I can’t *remember which author wrote
what. I do recall that someone with lots more *knowledge than myself (Susan Garlinghouse?
TI?, or maybe summarized by Dr. Weary) *wrote that the meals eaten during a ride have little to do
with gut sounds at the *vet
checks as it takes so long for food to get into the gut where all these sounds *we like to hear are formed.
Nope, not quite, just a
few things turned backwards. It will take awhile for SOME nutrients to be
absorbed and make an impact on performance, but gut sounds can be affected
almost immediately after ingestion, depending on the amount of gastric stretch
they provide. Anything that stretches the stomach triggers the release of
the hormone motilin, which in turn triggers hindgut peristalsis and the gut
sounds vets are listening for. More stretch, for a longer period of time,
equals more motilin release and more gut motility. ANYTHING that
stretches the stomach will do, including water. However, most horses won’t
drink enough water at one time to significantly stretch the stomach, plus water
sluices through semi-immediately. Foods that are highly concentrated and
fed in relatively small amounts, like rice bran and grains, don’t stretch
the stomach very much, but do have a somewhat longer effect before the stomach
empties. Big, bulky foods, preferably made even bulkier with water,
stretch the stomach more, and hold the stretch longer, thus produce the most
motilin release for the longest period of time, and therefore produce the
highest response in hindgut peristalsis. The reason I like soaked beet
pulp over hay plus a drink of water, is because the beet-pulp-and-water become
an integral unit, and I think produce better gastric stretch. I don’t
have specific data to back that up, though, it’s just an opinion.
Instead, what is important in keeping good gut
motility is good hydration and electrolyte balance and readily available energy
(glycogen?) fed frequently throughout the ride to keep all systems functioning
properly.
Yes.
If the horse runs low on energy or fluids,
systems start slowing down, gut sounds diminish.
More so fluids than
energy.
So, if the horse frequently eats small amounts
(a pound or so) of oats or carrots (not beet pulp, not enough glycogen?), then
they will actually have more energy to keep their guts operational and may even
stimulate them to eat more hay which will eventually get to the hindgut, but not
for quite a while. Did
I get this right?
Pretty much. The
energy provided by hay (or beet pulp) actually during a ride is moderate at
best, depending on its composition, because the fermentation pathway is
slow. The hay eaten during the actual ride on Saturday benefits primarily
hydration and gut motility, and to a lesser extent, energy. If you’re
feeding a source of non-structural carbohydrates, those will benefit energy,
but does very little for hydration or gut motility. It’s a
balancing act to get it all right, but the primary bone of contention between
TI and I over the years was that I felt hydration and motility needed first priority,
and Tom thought sufficient energy would cover all three bases. We
disagreed, but it sure was fun.
And does anyone remember how long it takes for food to
get to the hindgut?
Depends on the type of
feed. As quickly as an hour or two, or as slowly as a day or so. High
fiber as a general rule moves slower, concentrates move faster, and move are
affected by things like water content of the slurry, electrolyte concentration,
things like that. Remember that the hindgut starts at the cecum, right
after the small intestine, and things can move pretty quickly through the
stomach and small intestine. It can take several days for high fiber
feeds to move completely through the entire hindgut and the colon.
