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[RC] What the Abstracts Say...and Don't Say (was: Beet Pulp) Part 3 - katswig@xxxxxxxxxxxxx

continued from part 2....

The second study:

Hydrolyzable carbohydrate intake in horse diets may become
excessive when rapidly growing pastures are supplemented with
grain-based concentrates. The substitution of fat and fiber for
hydrolyzable carbohydrate in concentrates has been explored in
exercising horses but not in young, growing horses. Our objective
was to compare bone development in foals that were fed pasture and
concentrates rich in sugar and starch (corn, molasses) or fat and
fiber (corn oil, beet pulp, soybean hulls, oat straw). Forty foals
were examined, 20 each in 1994 and 1995. In each year, 10 mares and
their foals were fed a corn and molasses supplement (SS) and 10
others were fed a corn oil and fiber supplement (FF). The
concentrates were formulated to be isocaloric and isonitrogenous, and
mineral content was balanced to complement the pastures and meet or
exceed NRC requirements. Dorsopalmar radiographs were taken of the
left third metacarpal monthly from birth to weaning and then every
other month until 1 yr of age. Bone density was estimated using
imaging software and an aluminum stepwedge. Radiographic examination
indicated differences in medial, lateral, and central bone mineral
content of the metacarpal III. Bone mineral content increased with
age, and a plateau was observed during winter. Bone mineral content
was lower in weanlings and yearlings fed the FF supplement than in
those fed SS. Subjective clinical leg evaluations indicated
differences in physitis, joint effusion, and angular and flexural
limb deformities in response to age, and possibly to season.
Regression analysis indicated positive relationships between bone
mineral content and body weight, age, and body measurements. Nutrient
and chemical interactions, such as the binding of calcium by fat and
fiber, may alter the availability of elements necessary for bone

What it says they did:
Over the course of two years they supplemented the pasture diets of 20
mares and foals with corn and molasses and 20 mares and foals with corn
oil, beet pulp, soybean hulls, and oat straw.  These two separate
supplements were formulated so that they had the same amount of calories
and the same amount of nitrogen, along with "balanced" minerals.

What it doesn't say:
It doesn't say what type of pasture the horses were on.

It doesn't say (because it can't say, there is no way to know), what effect
on pasture grass consumption the supplements had (so there is no way to
know what was "taken out" of the horses diets by having been supplemented).
In fact, because there is no way to monitor pasture grazing consumption of
the horses in question, there is no way to know exactly what these horses
were being fed; consequently, while the coloric content of the supplements
was created to be the same, the caloric content of the entire diet is
unknowable (this is not irrelevant).

It doesn't say that the mineral content of both supplements was the same,
only that they were balanced to the pastures to meet or exceed NRC

What it says they observed:
Through evaluation of x-ray it appears that mineralization in the left
front coffin bone was less in the horses fed the fiber and fat supplement
than for those on the corn and molasses supplement; however, that this was
also correlated to age and size.

It also says that they observed some differences in joint development and
limb deformities, and that these appear to correlate to age and season.

Bone mineralization was also affected by season.

What it doesn't say:

No mention is made of differences in joint development and limb deformities
being correlated to diet.

It doesn't say what the effect of beet pulp is because none of the horses
were supplemented with just beet pulp.  It is impossible to separate the
effects of beet pulp from those of fat, soy hulls and oat straw included in
the fat and fiber supplement.

There were no mares and foals in the study on a "control" diet (i.e. not
supplemented at all); consequently the effects of increased bone
mineralization in the horses supplemented with corn and molasses v. those
supplemented with fat and fiber may not be because the fat and fiber horses
are getting beet pulp, but rather because they are not getting corn and

No mention is made of observing or monitoring the exercise that these foals

While the authors of the study speculate in the abstract that the lowered
bone mineralization observed in the fat and fiber supplemented horses might
be because fat and/or fiber might bind to calcium and make it unavailable,
it is certainly not the only explanation.

Since it is well documented that bone density is a function of
activity/concussion, the observed differences in bone density could be a
result of increased activity of horses on a sugar high rather than because
beet pulp affects mineral absorption.

It is also well documented (and is even confirmed by this study with the
correlation of bone density to age, weight and size) that bone
mineralization responds to the impact/concussion of having to carry around
more weight, and that despite the fact that the supplments contained the
same number of calories, that the overall diet of the corn/molasses
supplemented horses had more calories because it was less bulky, could be
consumed faster, and therefore did not reduce the pasture intake of the
foals as much as the fat fiber supplement did.


Most importantly, what none of these abstracts say is this (Tom Ivers 31
July, 2005):

The gist of the papers is that beet pulp acts as a modest chelator.
It does attach itself to forms of metals (minerals)and pull them out
of feedstuffs to be eliminated. It does so enough to compromise bone
density and bone mineral content in growing foals. It also limits
digestion of other macro-nutrients, carbs and fats in the case of the
paper included in that small batch submitted. In contrast, plain hay
contributes some minerals and other micronutrients to the blood

1. Not once is the word chelate mentioned although the bone mineralization
study alludes to the possiblity that calcium might bind to fiber or fat.

2. Not all minerals are metals (calcium comes to mind).

3. The effect of feeding beet pulp on growing foals cannot be separated
from the effect of feeding fat in the form of corn oil as well as soybean
hulls and oat straw.

4. Nowhere in any of the abstracts does it say any of the subjects were fed
plain hay, let alone what effect doing so may have.

5. The only analysis mentioned of what is in the blood stream were the
plasma concentrations of amonia and creatinin, neither of which is a
micronutrient, so none of the studies mentions anything about what effects
any of the dietary variations (including hay or beet pulp) in these studies
has on micronutrients in the blood stream.

Nor does it say this (Tom Ivers 1 August, 2005):

It means that beet pulp does interfere with mineral absorption
in the horse--to the extent that its feeding in foals results
in measureably weak bone.

I refer you to note 3 above.

However, (and here I confess to having cheated slightly, by reading beyond
the abstract provided by Tom), in the bone mineralization study in foals
the authors provide the following implications:

"In growing horses, metacarpal bone mineral content increases may be
modulated into seasonal waves with two plateaus, the first by a change in
diet from mainly milk to mainly pasture and supplement, the second by a
decrease in activity on ice and packed snow. Differences in energy source
of concentrates fed in supplement to pasture may influence metacarpal bone
mineral content in growing horses. Horses consuming diets containing fat,
which may form calcium soaps, and fiber, which tends to capture cations,
may have an increased requirement for calcium and other minerals. Nutrient
and chemical interactions may alter the availability of elements necessary
for bone development."

So, it may be that the conclusions Tom leaps to that are not supported by
reading the abstracts are because Tom did as he himself suggested and only
read the first and last lines of the abstract, rather than reading the
whole paper.  Because, certainly, the authors of the paper, in their
implications readily acknoledge that bone mineralization is most likely a
function of energy and activity; although it might have something to do
with feeding fat because fat can bind to calcium or by feeding fiber.

"Nutrient and chemical intereactions [of diets containing fat and fiber]
MAY (emphasis mine) alter the avilabiltiy of elements necessary for bone
development" is a LOOOOOOONNNG way from saying "feeding beet pulp to foals
results in measurably weak bone."

So if I read these abstracts, they raise some questions that suggest
further investigation, and, what this "science" tells me is that they don't
KNOW very much.

But what I do know is that I have little faith in Tom Ivers's ability to
glean relevant information or report rational conclusions (if there are any
to reasonably be drawn from the avialable data).  Not just because the
summation he provided in his post of 1 August is not supported by the
abstracts he provided in his earlier post of 31 July but also because it is
difficult for me to give any credence the rational abilities of any person
who is so easily provoked into irrational invective, since he did so in
response to Steph's virtually innocuous request of, in essence, "could you
please explain?" while attempting to avoid provoking him by stroking his
ego with, in essence, "you are so much smarter than all of us."

This does not mean that he cannot provide useful information.  Certainly he
has investigated a great deal of the available literature with respect to
what is currently being investigated, and, as a consequence, can provide a
useful bibliography for anybody who wants to do any investigating on their
own (and make no mistake this is an EXTREMELY valuable service).  However,
I would be leary of taking any of his advice without confirming the source
for yourself, since he has demonstrated a proclivity for leaping to
conclusioins not supported by the data.  And I would take it as a given
that if you ask for clarification that he will jump down your throat.  This
jumping down your throat MIGHT also include more bibliographical
information, in which case you could get additional valuable information so
long as you can ignore the accompanying invective; which isn't really all
that hard to do.

Because I find the bibliographical information extremely valuable (it is,
in fact, in essence, what the Internet was invented for, scientists who
wanted to be able to hyperlink to relevant papers), I am thrilled that he
has joined us to provide this information. Just be careful about accepting
his conclusions or asking him to interpret things for you.  In this, I have
found him to be less than 100% reliable.

Orange County, Calif.

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