Some Hot Weather Lure Coursing Tips

                        
                              by Bonnie Dalzell
                        
                               May 31, 1995

Hot weather coursing is very tricky as heat exhaustion is one of the 
major things limiting athletic performance in dogs. They can build up an 
enormous amount of heat in the 60 seconds that a course lasts and if 
there is a break in the course and they stand around in the sun before 
being rerun you can have a dog go into heat stroke.

There are several important physiological factors to understand
 
 * Heat is lost from a body by evaporation, radiation and convection (mass 
transfer).
    
    Sweating cools you by evaporation

    Glowing white hot and cooling to red hot would cool something by 
radiation - this is not particularly applicable to most animals as we 
know them. However black animals re-radiate heat better than white animals.

    Being submerged in cold water, having a breeze blow on you or having 
water from a hose run over you are all ways of having convective cooling. 

    If it is very humid then evaporative cooling is relative ineffective 
and convective cooling becomes the most important mode. 


 * Dogs do not sweat to cool off. They get rid of heat by panting and 
submerging in water. After they submerge they can get out of the water 
and loose heat as the water evaporates but they will need to submerge 
again to restore a water film once they dry off.

 * the ability to generate heat is proportional to the dog's body mass

 * the ability to cool off is proportional to surface areas:

tongue, ears, inside of mouth, lung surface, legs and the rest of the body.

  Since mass increases geometrically but surface area increases 
arithmetically larger and bulkier dogs overheat MUCH more easily than 
smaller and thinner dogs. 

  In practical terms. If you have a large dog or a hairy dog just misting 
its coat with a spray of water from a mister on a hot humid day is NOT 
going to cool the dog off. Neither is allowing it to drink a lot of water.

  The  dog needs to be submerged or hosed down and it needs to be in the 
shade. If the dog has just run it should be walked to aid in cooling but 
this does not substitute for hosing down or submerging.

  Since dogs obtain a fair amount of evaporative cooling through heavy 
panting the dog's mouth can be moistened. 

  A hot dog should not stand around in a muzzle. The muzzle can seriously 
interfere with panting.

  Dogs in heat stroke may feel clammy to the touch. While going into 
heatstroke they may produce copious quantities of thick, ropey saliva.
Seizures can be a consequence of heat stroke.

  Dogs are more sensitive to heat and high humidity than humans. A 
situation that may be merely very uncomfortable for you may kill your dog.

  Dogs take longer to acclimate to climatic changes involving increased 
heat and humidity than people and they will loose that acclimation over a 
period of cool weather. Just because your Borzoi or Irish Wolfhound was 
fine last summer does not mean that you can take it out and run it for 
the first time THIS year at a July trial in Florida! 

  Judges at lure coursing events should keep in mind that the larger and 
faster breeds are much more susceptable to heat stroke than small breeds 
and deport themselves accordingly in relation to reruns and starting 
courses over. 

  Field trial committees should strive to allow 20 minutes between runs 
for any given dog (as is the case in reruns and a Best of Breed of Best 
In Field following a run off).

Remember the purpose of the sport is to test the athletic ability of the 
dogs but not to test it to destruction!


 In my opinion mid summer trials should have copious shade 
and water 
available or be limited to Basenjis, Pharaoh Hounds and Ibizan Hounds.

I think it is quite thoughtless of field trial committees to put on a hot 
weather, humid climate trial in one of these low lying, treeless, flat 
fields with no water and then absolve themselves of responsibility to the 
dogs by saying "contestants should bring their own shade and water".

Hot weather dry climate trials (as in the summer in Colorado) are not 
particularly hard on the dogs. It is the humidity that kills.

Dogs can get heat stroke in 80 degree weather if it is humid enough.


 ~~~~~~~~~~~~~~~~~~~~
Bonnie Dalzell, MA

freelance anatomist, vertebrate paleontologist, writer, illustrator, dog
breeder, computer hacker and iconoclast

bdalzell@clark.net
~~~~~~~~~~~~~~~~~~~~
mail: 5100 Hydes Rd
      Hydes MD USA 21082
phone: 410 592 5512