Too Hot to Trot?

The glory days of summer are upon us! Schooling, showing, and long trail rides keep us busy

through the week, while competitions, shows, and equine getaways entertain our weekends. As

the days get hotter, the demand for performance continues. We push ourselves and our horses

to the next level to work towards new goals and experiences. Although horses are generally well

adapted to hard work in many climates, the extreme heat of the summer can put our horses in a

hazardous position. What are some of the dangers that heat can cause in a horse? How can we

help keep our horses cool and conditioned for a high summer workload? Where do we draw the

line in order to keep our equine partners safe from high heat hazards?



Preceding the Olympic Games 1996 in Atlanta, a cooperative international research effort

identified key strategies for safe competition in hot and humid conditions.This knowledge was a

major factor that these Olympic Games proceeded successfully with no incidents, unlike previous

events (Barcelona 1992) where several horses collapsed during and after the cross country phase.

Hong Kong 2008 was another milestone in research as the international equestrian community feared 

the extreme humidity of Hong Kong. I was lucky to have been able to take

part in Pre-Olympic Heat and Humidity workshop organized by the FEI in Lausanne and

experienced first hand how meticulously these events were planned and how well the venue

and teams prepared for the conditions in China.

While my dreams and your dreams to make it to the Olympic Games might not come true, the

lessons learned and knowledge gained from our elite athletes are very much applicable to our

daily (horse) life.


So what are the dangers? Overheating and loss of electrolytes will lead to heat exhaustion and

Hypothermia ultimately leading to heat stroke, if we do not intervene and help in time.

The horse’s muscle produce an tremendous amount of heat, this heat is transported via the

bloodstream to the peripheral arteries and increases the skin temperature while sweat glands

are activated and the secreted ration of water and this radiation of heat helps to cool the body

down. About 85% of the heat is dissipated via sweat and another 15% through the respiratory

tract via panting.


Heat stress will lead to heat exhaustion which will lead ultimately to heat stroke!

The symptoms of heat exhaustion are:

Profuse sweating

Muscle weakness

Stumbling

Rapid breathing

And increased body temp over 102 F (38.9 C)

Once the body's compensatory mechanisms are overwhelmed, heat stroke will develop:

The skin will feel hot and dry

Massive rapid panting,

Rapid irregular pulse

Temps above 106 F (42 C)

Delirium

Convulsions

Death


What to do?

How to cool down the horse most efficiently?

Here are the instructions established for Hong Kong 2008:

● The horse should be covered from head to tail in cold water

Both sides continuously for about 30 seconds

You can use buckets or hoses

● After that walk the horse for about 15 seconds

This short period of walking will promote circulation and maintain skin blood flow.

● There is no need to scrape water off the horse at any time during the cooling

procedure - the thin layer of warm water close to the skin will be displaced by more cold

water.

If the horse tolerates it the horse can be hosed down while walking, but don't let horse

stand - we want the blood flow going from the muscles to the skin.

● Again - It is more efficient to NOT SCRAPE, but to keep re-dousing with cold water.

● When do we stop?

● When the rectal temperature is at least below 39C /102 F - and yes when you are done

with the cold water and the horse has cooled down - then you can scrape.

Taking rectal temperature immediately after exercising might be misleading as it tends to lag

behind core and muscle temperatures. it is not uncommon for rectal temps to rise 5 to 10 min

after exercise.

It takes about 10 min of intensive cooling to reduce the body temp by one degree C.

For example many horses finishing the cross country portion may have critically high

temperatures close to 42C (>106 F). So in order to get the body temperature down to normal it

can take 20 to 30 min of intense cooling efforts.

Common mistakes:

● Underestimating the amount of water that needs to be applied!

● Concentrating on avoiding specific areas of the body rather than using the whole horse’s

surface.

● Not allowing short periods of walking during the cooling.

● Not allowing to drink cold water after exercise

The myth that this will lead to colic has been debunked by the University of

Guelph and Illinois since 1995

● Despite the name, no coolers on an overheated horse!

● Over supplementation of electrolytes

This can actually increase dehydration as excess sodium stimulates the kidneys to flush

it out. The perfect balance with water is necessary.


So how hot is too hot to trot?

A simple guideline is the HEAT INDEX:

Simple tool: Temperature (in F) + Humidity

If the sum is below 120 there should be no significant problem.

130-150 - your horse will sweat - but will most likely deal with it if the horse is well adapted.

Make sure to cool down properly and allow your horse access to water and electrolytes.

Above 180 - don’t even think about it! Stay home or go for a swim with your horse.

Keep in mind that there is a huge variability in heat tolerance between individuals and breeds.

Body type and body composition is also a factor. For example I have found that especially

some Friesians have problems to adapt and perform under hot and humid conditions - so

please don’t try to keep up with your friend’s lean Arabian. Be sure to be conscious of how your

individual horse reacts to and performs in each climate. Know the signs and know the limits.

Now go out, stay safe, and enjoy your horse!

Winter – The Joys of Living in the Great White North.

Although winter has given us a break up until now, chances are that this will change soon.  Horses are very well adapted to cold weather, and the feral horse population in the Northern hemisphere survives without blankets and snow pads.

Researchers found out that the Prezwalski horse “Equus ferus Prezwalski”, which is a very close relative to our modern horse  “Equus caballus” has, apart from a thick hair coat, the ability to down regulate its metabolic rate in order to conserve energy when food is scarce in winter. Despite that, during the extreme cold winter 2009/2010 in the Gobi Desert in Mongolia the re-introduced wild P-horse population crashed dramatically.

The wild horse population in North America is also well established and makes it through the harsh winters out West. While the population survives, the unlucky individual animals who are, for whatever reason weakened, will perish in the cycle of life and death according to the laws of natural selection and survival of the fittest.

We took care of natural selection by breeding performance horses that can jump, do fancy dressage moves, or race around barrels. I am not going to start a “to blanket or not to blanket” discussion, but the fact that we did take control of the breeding selection of our horses, means that we also have to take control of our horses’ comfort requirements (not only) during the cold season:

• shelter from wind chill,
• keeping horses dry, 
• meeting the horse’s energy requirements,
• water supply,
• and foot care.

Shelter Size  
According to the University of Minnesota, a general rule-of-thumb for run-in or open-front shed size is 240 square feet for 2 horses (i.e. 12 x 20 feet), and 60 square feet (i.e. an additional 10 x 6 feet) for each additional horse. These recommendations assume horses housed together get along well.

Keeping Them Dry  
These are the UoM suggestions and guidelines to blanket a horse if:

• There is no shelter available during turnout periods, and the temperatures drop below 5°F, or the wind chill is below 5°F.
• There is a chance the horse will become wet (not usually a problem with snow, but much more of a problem with rain, ice, and/or freezing rain).
• The horse has had its winter coat clipped.
• The horse is very young or very old.
• The horse has not been acclimated to the cold (i.e. recently relocated from a southern climate).
• The horse has a body condition score of 3 or less.

Proper blanket size and fit is important, in order to avoid rub marks or even injury. The proper type of blanket according to outside temperature is essential, a rain sheet alone has no insulating properties and can make it even worse, by compression of the insulating air-cushion formed the horse’s hair coat.

Feeding Requirements
The temperature below which a horse needs additional energy in order to maintain body warmth is called the lower critical temperature. This lower critical temperature in a horse with winter hair coat is about -7°C, for a clipped or horse with summer hair coat, it is about +7°C. The energy demand will increase about 1% per degree below that temperature.

In young horses their growth can be “put on hold” at low temperatures with a lack of nutritional energy.

Sometimes a thick hair coat can mask a poor body condition, especially in older ponies,

Water
Unfortunately, we see an increased number of impaction colics at this time of the year. Horses consuming winter feeds, have increased water requirements. Hay and grain normally contain less than 15% moisture, while in contrast, pastures possess 60 to 80% moisture. Even if quality feed is offered, horses will consume less if not drinking enough water. Fecal contents must maintain adequate moisture levels. If fecal material becomes too dry, intestinal blockage or impaction might develop. A horse will most likely not develop an impaction in one day, but can over several days to several weeks of inadequate water consumption.
The water in the waterers needs to be heated above freezing, adding one or two tablespoons of salt per adult horse is a good idea, as this will stimulate drinking.
Waterers should be cleaned regularly, and clean, fresh water needs to be always be available, regardless of temperature.
Foot care
Snow pads are absolutely necessary if your horses are shod and there is snow on the ground, as snow will otherwise ball up under the shoes and sole, creating a significant injury risk. If bare foot, please consider that frozen ground can lead to sole bruises and foot concussions.

Having said all this, let’s hope it is going to be a short one!