(Fwd) winter dehydration in horses

["Judith Lessard" <lessardj@cvm.msu.edu>]

In response to the posts about horses drinking cold water, I thought 
perhaps the following information from the College of Veterinary 
Medicine at Michigan State University could be helpful.

This press release, and others, can be found at:

http://cvm.msu.edu

click on News/Events, and scroll down to "News Releases"


WINTER DEHYDRATION IN HORSES

Contact: Ken Gallagher, DVM, MS 
Equine Extension Veterinarian 
College of Veterinary Medicine 
Michigan State University

It's a little known fact that horses can actually be thirstier in the
winter than they are in the summer.

"During cold weather, especially if the humidity is high, a horse's
thirst mechanism does not always function as efficiently as it does in
the summer," said Ken Gallagher, a Michigan State University College
of Veterinary Medicine Extension equine veterinarian. 

Some water is lost from a horse's body every day through the urine,
feces and moisture in breath exhaled from the lungs. If the horse is
performing during cold weather, significant water can also be lost
from sweating. 

Dehydration occurs if a horse loses too much water from its body and
does not replenish it, or if a horse just is not consuming enough
water every day to meet its bodily needs. A three to four percent loss
of body water will cause mild dehydration. 

Some horses will only drink five to six gallons of water per day, eat
normally and remain healthy. "These horses are the exception; their
kidneys have the ability to concentrate urine and recycle more of the
water back into the body," said Gallagher. 

Most horses are not capable of this kind of kidney function and should
be provided adequate, good quality water. Most adult horses weighing
1,000 lbs require a minimum of 10 to 12 gallons of water each day for
their basic physiological needs. 

Goodquality water must be free of harmful germs, foreign material,
excessive minerals, environmental pollutants and unusual flavors. 

Occasionally, horses will eat snow if it is available and cut back on
drinking water somewhat. "Horseowners should not depend on snow as a
water source and should provide an adequate water supply," he said. 

Regardless of season and weather conditions, horses should have water
every day in plentiful supply. 

It is the most important nutrient, because it is needed for almost
every bodily function: it helps to maintain appetite and proper
moisture level in feed and feces, maintains normal blood volume and
aids in the normal function of sweat glands. 

There are two common complications resulting from inadequate water
consumption during cold weather. 

The first is decreased feed intake. "Even if goodquality feed is
offered, the horse will cut back on consumption if it is not drinking
sufficient water," said Gallagher. 

One reason for this is the lack of saliva to mix with the feed as it
is being chewed. A normal adult horse in a state of good hydration
will secrete up to 10 gallons of saliva per day to help soften the
food mass as it is chewed and swallowed. 

If the appetite is affected and less feed is consumed, the horse might
not receive enough energy to tolerate the cold weather, he said. 

The second, and potentially more harmful complication, is impaction
colic or constipation. Both the feed material during digestion and the
fecal contents after digestion must maintain adequate moisture levels
or they can cause a blockage in the intestinal tract. 

A horse will not become impacted in one day from decreased water
consumption. The process usually happens over several days to several
weeks. "If the horse becomes chronically dehydrated over a period of
time, the body reserves are lowered and a blockage can occur," said
Gallagher. 

The usual signs of an impending impaction colic are depression,
decreased appetite and decreased production of manure that is drier
than normal. If these signs are observed, a veterinarian should be
called. Early detection usually means the colic can often be resolved
without requiring surgery. 

Always provide adequate, goodquality water, preferably on a freechoie
basis. If horses are given access to a tank or automatic waterer,
consumption cannot be determined accurately. 

Owners should watch for signs that these horses are not eating well or
becoming lethargic. If horses are watered from pails, either by hand
or in a stall, be aware the stomach capacity of a 1,000pound adult
horse is only five to six gallons, so it is difficult for them to
drink more than that amount at one time. 

Two waterings per day will provide only the minimum amount of water
needed. Under those conditions, a horse should have an opportunity to
drink more frequently, especially if the horse is performing. 

Previously, it was thought the best water temperature for horses was
from 45 to 65 degrees, and if the water got colder, many horses would
decrease consumption. This was especially true of horses 12 years of
age or older whose teeth are sometimes more sensitive to cold water. 

A recent study of water consumption by ponies during cold weather
indicated warming the water well above freezing temperature resulted
in approximately 40 percent more water consumed per day. 

It probably is not necessary to increase the water temperature a great
deal for every horse, Gallagher said, but it would be worthwhile if
consumption is below normal or if a horse has a tendency to get
impacted. 

Increasing salt intake might also stimulate a horse to drink more. The
idle, adult 1,000pound horse should be consuming about two ounces of
salt per day. If salt has been added in a commercial grain mix, an
owner can offer the horse an additional handful of loose salt in the
grain box or provide a salt block. 

                                                  #######

For the person who asked what we do here in Michigan, for years I 
used a metal watering trough.  In the winter I use a submersible 
stock tank heater.  I use the solid styrofoam insulation that can be 
purchased at a building supply -- it is used to insulate houses, etc. 
It comes in 4 x 8' sheets.  I cut one piece and put it on the ground 
under the trough.  Then I place a heavy-duty plywood "box" over the 
trough, and stuff pieces of the insulation board down along the sides 
-- pack it in tight.  I use as large of pieces as I can on the sides 
and the ends, and then pack in as necessary, little chunks here and 
there.  

On top, we built a lid that covers 3/4 of the surface area, and
added and edging to fit down over the plywood box -- to help prevent
the horses from sliding it off--plus at times I've put a cinder
block on top as well.  We cut out a small chunk of wood at one end,
for the heater cord to come up through.  Plus, to be sure the horses
didn't mess with the electrical cord, I put a piece of black
flexible drain tile over it.

Needless to say, this all makes it difficult to clean the trough. 
Rather than take it all apart, I bucket it out every few weeks as
best as I can.  Since I have angora goats that drink out of it, too,
I fill the trough daily.

Some years, for further protection, I have put the trough inside the 
horse lean-to (built on the back of a 100-year old bank barn) to keep 
it out of the wind and help keep the electrical bill down.  I put it 
in a small doorway, 1/2 in the horse lean-to, and 1/2 in the basement 
of the barn -- the horses drink out of one end, and the angora goats 
out of the other.  -- To do this, I made another, smaller lid that 
allows an opening at both ends, and the heater cord comes up out of 
the center of the cover. 
Judith Lessard
Editorial Assistant
Publications and Media Relations
College of Veterinary Medicine
Michigan State University
East Lansing, MI 48824


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