A couple of thoughts on overheated dogs. Link:
Increased Body Temperature and Heat Stroke in Dogs
Signs you are likely to see in the field:
- Panting
- Dehydration
- Excessive drooling
- Increased body temperature - above 103° F (39° C) [It's worth it and easy to carry one of those child rectal thermometers in the vest. 105° is definitely too high]
- Reddened gums and moist tissues of the body
- Changes in mental status
- Seizures
- Muscle tremors
- Wobbly, uncoordinated or drunken gait or movement
"Some external cooling techniques include spraying the dog down with cool water, or immersing the dog's entire body in cool –
not cold – water; wrapping the dog in cool, wet towels; convection cooling with fans; and/or evaporative cooling
(such as isopropyl alcohol on foot pads, groin, and under the forelegs). Stop cooling procedures when temperature reaches 103° F (using a rectal thermometer) to avoid dropping below normal body temperature.
It is very important to avoid ice or very cold water, as this may cause blood vessels near the surface of the body to constrict and may decrease heat dissipation. A shivering response also is undesirable, as it creates internal heat. Lowering the temperature too quickly can lead to other health problems, a gradual lowering is best. The same guideline applies to drinking water.
Allow your dog to drink cool, not cold, water freely. However, do not force your dog to drink."
I carry a couple of pint bottles of isopropyl alcohol in the truck and a quick read kids unbreakable rectal thermometer in the vest. Reports I've read said you can drop a dogs temperature several degrees in minutes using the alcohol. The don't use ice cold water thing is very important. My hunting buddy is my vet. I asked about just putting an overheated dog in an icy pond. He clearly stated that would make the situation worse. Cool, not cold, is what you want.
Obviously keep them hydrated. We both carry a 5 gallon jug of water in the truck for the dogs. They get a shot a a full pan of water before and after every field we hunt. Water is cheap.
<EDIT> You don't want them drinking out of ponds/water that cattle have used either. Check out leptospirosis. I lost a GREAT pointing Lab to lepto years ago before anyone really talked about lepto and before they had the 4 way lepto vaccine. All my dogs get the vaccine 6 weeks before hunting season. It takes time to take effect. Won't protect against all strains of lepto but...you do what you can.