Polar Products makes cooling wrap collars for dogs and other animals. We also bought a long-lasting Polar Pet Pad for Shasta to sit on while traveling through hot summer days. (Maybe we should have bought two more for us!) His pad stays cold for about 24 hours without ice or refrigeration. Recommended for vintage car pet passengers!
Where in the world are the Gills? 
Hi Mr and Mrs Gill! Hope you are having a great summer and good luck on your trip!! We will follow your trip online! Love, Audrey + Marie