electrolytes

[Michael I Lindinger <mlinding@uoguelph.ca>]

I will take some time to respond to a number of electrolyte related emails
over the past few weeks.

One query related to how much electrolytes and how often.

The answer depends on the composition of the product, how well the
horse is drinking, and how much the horse is sweating. For Perform'N Win,
which is about 50% carbohydrate by weight, nearly twice the mass should be
used compared to an electrolyte supplement that has no carbohydrate but
a similar proportion of the salts. (The carbohydrates are in Perform'N
Win to enhance uptake of the salts in the gut, but also provides sources
of readily available energy for muscles and help improve the taste). In
general we recommend 3 oz of PNW in
1 gallon of water and to try to administer 1 gallon per hour of exercise.
this is fine so long as the horse will drink the solution out of a bucket,
but this is often not acheivable during rides. What most people do is
administer 2 to 4 one oz syringes with water (to make to make a slurry)
into the horses mouth. This technique means that you must monitor how much
water the horse is drinking, as not enough water (i.e. 1 quart per
syringe) can contribute to problems and not help the horse. Again, most
people do administer at vet checks, many administer whenever the horse
drinks (pit stops, creeks) which is a recommended practice. At a ride like
the Biltmore it is nearly impossible to replace the water and salts lost
through sweating -- one can only try to give as much as possible so long
as it is balanced with water.
	Also administer before the ride as much as you can get on board,
and after the ride as much and for as long as you can. The electrolyte
powder can be srinkled on liberally wet (read soaked) feed.

Human Electrolytes
I too use Perform'N Win when/after I run in the summer. I too like the
taste and it is cheaper than human products, especially if you have it
around for your horses. I mix about a 1/4 oz in a liter of water, much
more dilute than used for horses, and drink 1/2 to 1 liter.. I like it
better when chilled and served cocktail style! 

Sarah asked about her horse which is just coming on but not sweating much.
Horses may not seem to sweat much but make actually sweat quite a lot. It
may be that the sweating rate is not excessive. When doing training rides
one should try to ensure that the horse has access to water (and the
preferred electrolyte supplement) at roughly 10 mile intervals, and stay
until the horse drinks. this takes great patience (initially) as the horse
must learn the new behaviour. this strategy pays off very well for many
top endurance riders. If you are not sure how much your horse is sweating
try to get body weights on the horse before and after a ride. The loss in
body mass is a good estimate of how much weight of water was lost as
sweat.

A question about anhydrosis. Anhydrosis appears to occur in all breads of
horses, but most Arabs do not appear to be prone to it. It is definitely
more common in Thoroughbred and TB crosses and in some warm bloods -- so
there probably is a genetic connection in its occurence.

The lather in horse sweat if due to the presence of a protein in sweat
called latherin. Its function is to act as a surfactant -- to spread the
sweat evenly over the surface of the body. I do not think that diet will
influence latherin's appearance. there also are some regional differences
in sweating rate (and probably composition) but not enough to worry about.
In general, sweating will start first in areas close to contracting
muscles (withers, gluteus) and spread from there.

A comment about Heidi's 'reference' to changes in horse sweat with
training. The values stated (1/10th the amount of electrolyte per volume
of sweat) are for humans, NOT horses. As I stated before there is no
evidence to support this in the literature and Marlin's work from
Newmarket (1996, 1997 in Equine Vet Journal) using horses with some
increases in conditioning supports this.

All for now, and safe riding!

Mike Lindinger