Jeannie Waldron, DVM
Electrolytes for endurance horses
For those of us new to this sport,
please help us understand the ins
and outs of electrolyting properly.
Trisha Dingle
Bishopville, SC
Electrolytes are discussed on a daily
. basis among endurance riders along
with dehydration, the "pinch" test, tying
up, and thumps. We hear comments about
electrolytes ranging from: "They're just
salt" to "All of life depends on them."
Many of us have been given a secret for­
mula, an easy way, the only way. We have
been told, "It's impossible to give too
much" and we've been told, "Too much
can kill them." It's no wonder that we are
confused ... and concerned.
I hope, after reading this article, you
can walk away with some facts that can
assist you in making intelligent decisions
regarding chOOSing and using electrolytes
in the end urance horse.
Electrolytes are necessary for life. They
are intimately involved in muscle contrac­
tion. l1eart and kidney function, and en­
ergy metabolism. In general, electrolytes
are required to make energy and energy
is required to place electrolytes in a posi­
tion to be utilized. This results in a deli­
cate balance. Without adequate electro­
lytes, no energy can be produced and
without adequate energy, electrolytes will
not be available at the necessary sites to
do their jobs.
Now for practicality
If your horse can not maintain hydra­
tion, he runs out of gas, fails to recover or
loses his appetite. It is safe to assume that
his energy and electrolyte balance has
been upset. If he has been conditioned
properly to do the job, and he carries
enough body fat to supply adequate en­
ergy and still runs out of gas ... it may
well be an electrolyte defiCiency.
When using an electrolyte product,
one should abide by the 10 golden rules:
1. Do not allow the administration
of electrolytes to interfere with your
horse's eating or drinking. Wait until
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your horse is leaving the stop before giv­
ing electrolytes. This will allow uninter­
rupted eating and drinking during his rest
period. Electrolytes have been mixed with
applesauce, yogurt, molasses, antacids
and the list goes on. A taste test has re­
cently revealed that molasses is far more
palatable than yogurt (by my taste buds l )
Certainly there are many choices. Also
some electrolyte combinations can cause
mouth irritation. Rinsing your horse's
mouth after their administration is a kind­
ness to be considered and may help with
this irritation.
2. The full 100% of losses may not
need to be supplemented. The bowel
acts to store an incredible amount and, as
long as motility and hydration are main­
tained, this constant source can be uti­
lized.
3. Preloading your horse with elec­
trolytes will be beneficial. It encourages
drinking, and the electrolytes are available
immediately upon demand. They will also
contribute to bowel storage. Lag time can
lead to poor recovery rates, loss of appe­
tite and other less obvious problems. They
should not have to play catch-up!
4, You must read the label and all
ingredients must be listed. Sugar should
not be first on this label.
~ ask the vet
Thirty liters of sweat containing the following
amounts of electrolytes may be lost in a 50­
mile ride:
• Sodium: 90,942 mg (three oz.)
• Potassium: 62,010 mg (two oz.)
• Chloride: 182,700 mg (six oz.)
• Calcium: 3720 mg (1/8 oz.)
• Magnesium: 1656 mg (1/20 oz.)
Horses, conditioned properly to ride 100 miles,
will usually recover some of these losses by the
end of the day, so these rJumbers are not found
to automatically double.
5. Chloride suffers the greatest loss,
therefore the largest significant
amounts must be included in the sup­
plement. If sodium and potassium are in
the proportion of three to one and in the
form of chloride salt, this wou Id satisfy
the needs of Na, K, and CI if sufficient
amounts are presented to the horse.
6. No bicarbonate (H 2 CO) should be
included in the electrolyte mixture used
in the endurance horse. Alkalosis is a
problem for the sweating animal and is c1
result of loss of chloride. Bicarbonate will
only increase this alkalosis making his
acid-base balance more difficult to
achieve.
7. Ca and Mg salts need to be in­
cluded. Acetate and citrate salts are rap­
idly absorbed (45%) and therefore benefi­
cial during competitions. Chloride, glu­
continued on page '-1-7
Sodium (Na) is an important electrolyte in acid-base balance as well as osmotic balance
of body fluids. Deficiency over the long haul can result in decreased water intake and a
slowed rate of eating. Acute deficiency can result in incoordination. The daily require­
ment of a 1000 pound horse at rest would be 1.5 grams and can go as high as 36 grams
per day in heavy work.
Calcium (Ca) is utilized in muscle contraction, blood clotting, enzyme utilization, nervt'
transmission, and energy production. Chronic deficiencies of calcium or improper bal­
ance of Calcium with phosphorus can result in weakening of bones and variolls forms of
lameness. Acute deficiencies, as we may see in sweating horses, can result in poor recov­
eries, thumps, muscle weakness, and erratic heart rates. Thumps is thought to be associ­
ated with poor availability of calcium.
Chloride (0) is closely associated with sodium and involved in acid-base balance, os­
motic balance, and digestion. Deficiency of chloride caused by heavy sweating wtll re­
sult in an alkalosis.
Magnesium (Mg) is an electrolyte associated with enzyme function and energy pro­
duction. It has been recommended that when a horse is in training and on a high fat diet,
as much as .18% of dietary magnesium may be required.
Potassium (K) is also associated with acid-base as well as osmotic balance of bod y flu­
ids. It is intricately involved with getting oxygen to working muscles. Acute deficiencies
can result in cramping of muscle mass and tying up syndrome. Chronic deprivation of
potassium may result in decreased appetite and weight loss.
-Jeannie Waldron, OVA1
May 2004 • Endurance News • 7
2004 5'L'E2{C ::A(ationa[Championship 2?jde
Warner Hot Springs Ranch
Warner Springs Ranch
(50 miles NE of San Diego, CAl
100 mile: Thursday, October 7
50 mile: Sunday, October 10
Barney Fleming, DVM, Head Veterinarian
• Scenic trail
• Beatiful private facility
• Cabins with fireplaces
• Equestrian center with
corrals
• Olympic size hot
mineral pool
• Restaurant & cantina
• Food for riders at
vet checks
• Hay & grain for horses
a( vet checks
• Soup, salad bar &
buffet banquet
Photos courtesy oJ John and Steph Teerer. www.endurance.net
As of April 5,2004, the fbllbwing AERC members have entered the
2004 National Championship at Warner Springs Ranch in October:
50 Mile National Championship
Junior
Amy Schneider
Featherweight
Monica Bennett
Holly Davies
Cynthia Hamberg
Deborah Huebsch
Suzanne Malden
Lisa Schneider
Lightweight
Tri.na Corder
Gary "Catfish" Daniels
Stacy Jett
Barbara Kempe
Tammy Robinson
Middleweight
Carl Bruno
Annette Jacobs
Darrell Jett
Wendy Lumbert
Shel Schneider
Heavyweight
Fred Cluskey
ask a vet: electrolytes
continued from page 7
conate and lactate are next in line at 25%
to 30% absorption. Carbonates are ab­
sorbed at the rate of 10% to 20%. Dolo­
mite is a calcium / magnesium / carbonate
complex and also has a fairly low absorp­
tion rate. All of these salts can be used but
an increased amount of the poorly ab­
sorbed electrolytes will be required. Some
riders have reported recovery of thumps
within 30 minutes with the acetate salt of
calcium. I can verify this in a few cases
but certainly not all.
8. Having free choice, trace miner­
alized loose salt available to your horse
at home is essential. The loose form is
consumed far better than block salt. Many
horses have sensitive tongues and don't
like to lick a salt block as readily.
100 Mile National Championship
Junior
Amy Schneider
Featherweight
Barbara Fredy
Sandy Prior
Lisa Schneider
Lightweight
Tammy Robinson
Kirsten Seyferth
Middleweight
Kirsten Berntsen
Carl Bruno
9. Do not give electrolytes on a dai­
ly basis in food or water. Constant pre­
sentation of high-level Ca will decrease
the ability of your horse to mobilize his
own calcium stores. Feed already contains
Significant amounts of electrolytes and
adding more may also decrease palatabil­
ity. One popular brand of quality sweet
feed contains the follOWing: Na 1360 mg/
lb.; K 3180 mg/lb.; CI 2700 mg/lb.; Ca
3600 mg/lb.; Mg 900 mg/lb. Compare
these to your electrolyte choice, remem­
bering the absorption rates. Supplying
loose salt is usually all that is necessary.
10. Alfalfa is an excellent source of
calcium. I would not suggest it be fed on
a regular basis if there are other protein
sources available. It is fed on a regular
basis to many endurance horses out west
with no observable problems. In the east,
Wendy Lumbert
Heavyweight
Charlie Robinson
Fred Cluskey
To request an entry, contact
Terry Woolley Howe
Ride Manager
505 N. Mollison #l03
El Cajon, CA 92021
(619) 440-3838
e-mail:
cancer(~networld.net
however, it seems to contribute to tying
up. I do not understand this.
I feel that overdoing electrolytes
would be a very difficult thing to do. Not
eating or drinking appears far earlier with
electrolyte deficie~cy than with an elec­
trolyte overabundance. An early sign of
too much salt in the diet might be soft
manure when otherwise you would ex­
pect a normal consistency. This connection
would be hard make in the excitable en­
durance horse. Being prudent but erring
on the heavy side would be less detrimen­
tal during the stress of competition.
Remember, electrolytes will not make
up for a poorly conditioned horse, but
they will allow all horses to compete clos­
er to their individual best.
¢>
Vet Committee member Jeannie Waldron, DVM
practices at Rectortown (VA) Equine Center.
May 2004 • Endurance News • 47