Re: Blood work for testing?
Posted by: "plwoodbury" DesertHorses@xxxxx plwoodbury
Mon Aug 27, 2007 11:41 pm (PST)
> I have a question; does anyone advise testing your horse's blood to
see what
> they are lacking in and supplementing with that analysis as well as
testing
> the hay? I had someone question me as to why I am testing the hay
and
> supplementing based solely on that when I don't know how each horse
> metabolizes the vitamins/minerals I am feeding to balance the hay?
I'm not
> trying to start an argument, I'm just honestly curious.
>
Melissa ~
This is a great question (and also a fairly common one).
Blood alone is a poor indicator of the whole body's mineral status.
The body works hard to maintain "hemostasis" in the blood within very
tight parameters for many minerals (especially the major minerals or
electrolytes). It does this in a variety of ways - drawing from
extracellular fluids or from stores within soft tissue cells
(potassium for example), drawing on calcium from bone stores, etc,
using complex systems and feedback mechanisms.
So using blood values alone doesn't always relect if the horse has an
excess or deficiency at the cellular level. For some minerals, using
a "fractionalized urine" test, when combined with blood levels can
show a more complete picture. For other minerals and nutrients, you
need to test for metabolites (what they are broken down into) of the
substance you're interested in. And for some, the most reliable (and
sometimes only) way to test is by actual tissue biopsies. Fecal
(manure) analysis is also used to evaluate absorption of many
nutrients.
All of these tests *can be done - and many *are* done by those who
can afford them (not unrealistic for high priced performance horses
where there may even be a clinic and full time vet in their barn).
But they are cumbersome and costly for the average horse owner. And
you will still need to analyze your feed to correct the excesses and
deficiencies.
So instead, what we do is rely on what is known (to the best of our
knowledge)based on the current research (much of which has already
been done using some of the above testing methods plus other
additional methods) about the horses' requirements (based on age,
weight, reproductive status and work load) and the interactions of
various nutrients. We can then analyze our forage and feed, compare
it to the known requirements and ratios, and correct defciencies and
excesses.
Much of the recent research has been condensed into one book -
"Nutrient Requirements of Horses", Sixth Revised Edition (National
Research Council 2007)which is available to anyone - some of it is
heavy reading but it contains a wealth of information useful for any
horse owner. The book is $89.95 at
http://books.nap.edu/catalog.php?record_id=11653 - or ask your public
library to obtain it.
Of course, as with any body of research, there is always newer
work going on - such as the work at VA Polytech that validated GI
ratios and RISQI in equines. And there are areas in which little
research has been done on equine, so your choices are either WAG
(wild a**ed guess which may or may not be safe) or extrapolating from
other species (supported by field trials whenever possible to
evaluate safety and effectiveness). We try very hard to avoid WAGs.
> Also, do the majority of people on this list just pour their
>minerals on top of their tiny amount of grain?
We experiment to see how our individual horses will best accept it -
mine get their flax-based supplement/salt/etc mixed in some wet beet
pulp and scarf it down, but I've been known to just top dress on some
plain hay pellets when I forget to soak the beet pulp.
Patti K
Vail AZ
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Messages in this topic (3)
12b.
Re: Blood work for testing?
Posted by: "Eleanor Kellon, VMD" drkellon@xxxxx drkellon
Tue Aug 28, 2007 2:11 am (PST)
Just a few quick comments on Patti's excellent answer. All blood tests
are a "snapshot", a flash in time of what the levels are at the second
you took the test. If the horse is in the process of absorbing let's
say a meal with supplements in it, the numbers will be different than
they are a few hours later, or early the next morning. Hair shows a
broader time frame, but like blood there are complicating factors and
it only tells you the past.
In reality, there isn't too much individual difference between horses.
Your horse's digestive tract is just like the horse down the street.
Digestive tract disease can cause problems, but we're not usually
dealing with that.
The bottom line is that the horse cannot manufacture the nutrients his
body needs from thin air. They have to come from the diet. Analyzing
the diet is the simplest, most direct, accurate and inexpensive way to
know what the horse is getting.
Eleanor