Build me a heat tolerant dog

I average 2 to 6 hogs every hunt. Dont get me wrong I have been skunked 3 times this year. I hunt for a living and do so almost every day of the year. I use RCD's along side of my strike dogs. I like to run 2 or 3 dogs out at a time during the heat. I use 3 to 5 sets of dogs every hunt. During the cold months 6 dogs out. I dont have to rotate the dogs as much when it is cold. I use hand cuffs to hold the hogs I take all out alive during the heat because I do not have time to clean them and they will spoil in a few minutes during our hot days. My dogs average 40 plus miles during coold hunts and 10 to 15 miles during hot hunts. This slow down is because I put the dogs up for a break every 5 miles or one catch. I run 48 dogs that are hunted every week at least twice. This time doesnt include training or the walker. Guiding hog hunts with dogs and hog removal is one of the things I do for a living.