We used to use a cooling collar type thing when I showed in AKC. You take a "shammy towel" and sew it to make a tube. Put velcro on each end to be able to close it. Then put velcro on each end to be able to secure it onto dogs neck. We used to fill with ice cubes or you can just dunk it in ice water ( we always carried an igloo cooler full of ice to shows) Here are a couple I found online Kool collars, but if you can sew a little bit these are easy to make.