dturm wrote: Sorry, I'm with your wife, and the vet needs to rethink his answer.
A car radiator cools without sweating and evaporation, the fan kicks on and it works better. Ever see your dogs ears when they are hot? Blood vessels all over the body dilate - enlarge with increased body temp and act like a radiator. Moving air (as long as the air temp is lower than the body temp) should cool quicker. Hairless areas and thin hair areas and areas with greater blood supply will cool more quickly than the dense hair covered areas.
Sweating that people do certainly cool more quickly and efficiently than dogs and the cooler the ambient temp the faster the cooling.
Interesting problem
Doug, DVM
The car radiator cools by moving air ONLY when the air temperature is LOWER than the Coolant temperature--which is almost always the case here on Earth. That is not always the case with a dog. Once the air temperature approaches the body temperature of the dog (about 99 -100 degrees) the fan will, do no cooling.
Now, again, if it is blowing cooler misted air, the evaporative cooling of the mist will do some good. But once it gets over 90 or so, the fan realy is not doing much good.
Alaska is next! Still trying to fit the pontoons to the RV so We can get to Hawaii!
Johnworth914 wrote: Once the air temperature approaches the body temperature of the dog (about 99 -100 degrees) the fan will, do no cooling.
The fan, in this case (air temp close to body temp), could still aid in cooling by exchanging less humid air for the air near the dog with increased humidity due to respiration and evaporative cooling on the tongue and in the respiratory airways (i.e. nasal cavities).
Dry 100F air aids in thermal regulation better than 100F humid air.
Johnworth914 wrote: Once the air temperature approaches the body temperature of the dog (about 99 -100 degrees) the fan will, do no cooling.
The fan, in this case (air temp close to body temp), could still aid in cooling by exchanging less humid air for the air near the dog with increased humidity due to respiration and evaporative cooling on the tongue and in the respiratory airways (i.e. nasal cavities).
Dry 100F air aids in thermal regulation better than 100F humid air.
A fan on a hot humid day is not going to cool down a body. the purpose is to PREVENT the body from OVER HEATING. I.E. to try and maintain their set point body temperature.
When a dog over heats the treatment is to put ice packs under the legs, belly, and their groin to try and quickly reduce their 'body' temperature, "back to normal".
On real hot days when I have to travel in the MH. I freeze quart bottles of water, place that in the front part of the crate and place a fan in front of the crate. Keeps them cool. The 'smart' ones pull the bottle towards them and lay on it.
I learned that trick from a 4H'er when I had rabbits, who btw expire at the drop of hat on hot days. You freeze a bottle of water and they wrap themselves around the bottle to stay cool, nature at work at its finest, smart little bunnies they were!
"We must be willing to get rid of the life we've planned,
so as to have the life that is waiting for us".
Evaporative cooling (how a dog thermal regulates) is easier with drier air than with more humid air. Increasing the convection around the dog helps remove the expelled humid air and exchange it with dryer air for increased evaporation off the tongue and in the airways. This would be especially true in an enclosed environment (i.e. crate).
The evaporative cooling rate may be slower than the cooling rate of thermal heat transfer from the blood vessels through the skin to the cold water bottle which is likely why you do not perceive the fan as "working". But the fan is aiding the dog with its thermal regulation (keeping it cooler). The physical act of panting releases heat due to the muscle contractions; this temperature increase is more than offset by the increased evaporative cooling (when evaporation is efficient). If evaporation is not efficient (due to too much moisture in the air around the tongue and being drawn into the airways) then panting is raising the body temperature.
AC helps us "keep cool' but it is not necessary for our thermal regulation just like a frozen water bottle is not necessary for a dog's thermal regulation. What it will do is reduce the need for a dog to pant (how it thermal regulates) which will make the owner feel better.
BTW, the "normal" body temp of a dog is 100.5-102.5. I routinely see temps around 103.0-103.5 this time of year with an excited dog that has just been in a car. We've seen way more heat stroke victims this summer, one died last week. I did a recheck on a patient yesterday and he was doing fine - two weeks ago he presented with a rectal temp of 109 (they aren't supposed to be alive at that temp). He hadn't been overheated very long (<15 minutes) and we got the temp down fast, lucky guy.
Any room air temp below the body temp should have some cooling effect. But it is pretty obvious greater heat transfer will occur with greater temp difference between room air and body temps.
Doug & Sandy
Jill (11yr old Golden)& Charmin (16 yr old something)
Henry NOW a camping cat
2008 Southwind
2009 Honda CRV
dturm wrote: Sorry, I'm with your wife, and the vet needs to rethink his answer.
A car radiator cools without sweating and evaporation, the fan kicks on and it works better. Ever see your dogs ears when they are hot? Blood vessels all over the body dilate - enlarge with increased body temp and act like a radiator. Moving air (as long as the air temp is lower than the body temp) should cool quicker. Hairless areas and thin hair areas and areas with greater blood supply will cool more quickly than the dense hair covered areas.
Sweating that people do certainly cool more quickly and efficiently than dogs and the cooler the ambient temp the faster the cooling.
Interesting problem
Doug, DVM
The car radiator cools by moving air ONLY when the air temperature is LOWER than the Coolant temperature--which is almost always the case here on Earth. That is not always the case with a dog. Once the air temperature approaches the body temperature of the dog (about 99 -100 degrees) the fan will, do no cooling.
Now, again, if it is blowing cooler misted air, the evaporative cooling of the mist will do some good. But once it gets over 90 or so, the fan realy is not doing much good.
Yep, totally agree. I don't understand why some are having a tough time understanding this concept. If we are talking about a TT that is sitting out in the temps we have right now which are 100+, higher than the dogs temp, a fan is not going to do much if any at all cooling.
The OP has not yet clarified if they are talking about an RV that also is AC cooled and they want the fan for extra cooling or not. That makes a big difference in what the correct answer is going to be.
A fan is absolutely going to make it cooler if the unit is air conditioned and the room temp is lower than the dog's body temp. But at this point I have no clue what situation the OP is referring to.
If this were my dog, I would not put it in an unairconditioned unit with only a fan in this kind of heat we are having right now. To do so might not kill him but certainly is not as comfortable for the dog.
Clinical studies in the field have measured body temperatures of healthy dogs after working 10min of >107F. These dogs were not suffering hyperthermia (due to failed thermal regulation).
Review the research lit (as I have) on Exercise Induced Collapse (EIC) and Border Collie Collapse (BCC).
BCSnob wrote: Clinical studies in the field have measured body temperatures of healthy dogs after working 10min of >107F. These dogs were not suffering hyperthermia (due to failed thermal regulation).
Review the research lit (as I have) on Exercise Induced Collapse (EIC) and Border Collie Collapse (BCC).
Well a dog lying around dormant in an RV will not have the elevated temps of 107 due to working, more like the 100 degree range, so an RV of 103 degreess internal temp is going to need more than a fan to cool off the dog.
All I have asserted is when the air temp equals body temp a fan will still aid in cooling when the ambient humidity is lower than the humidity of the exhaled air from the dog. A fan will aid in cooling on hot days.
Your example fails (air temp above 103) if the humidity is low; if this were not so, then canines (dogs, coyotes, foxes, etc) in the southwest would be dropping dead all summer long.
I don't know much about the clinical study of the effectiveness, or efficiently of fans, an I don't have a dog in this discussion (because “The O.G.” is always cool’in off with the ac).
But the Clinical Science Dept. of Anonymous says to place two wet towels in the freezer (three, maybe four if U have a really BIG freezer). When they freeze, take one out, unfold, then place it on Dog. When it becomes unfrozen, re-wet, place it back in the freezer, take the other frozen one out, and repeat!
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