Last year I took my australian shephard in to get shaved for the summer. They told me it is uneccesary, that the undercoat acts as a regulator. Not only does it trap the heat in the the winter, but it traps the cool in the summer. I asked my vet, and he says that is true, both with my aussie and husky. I also provide access to the garage and plenty of cold water for them. I have a kiddie pool I fill up and the dogs get in it.