I believe that when many people say or hear the word "shave" they think naked. (think: as short as after surgery) This is not really the case. YES, it is short, but no shorter that a short haired breed (i.e. Doberman, Chihuahua)

And the problem with the thought that the dog's coat "insulates" against the heat is only true of a COMPLETELY brushed out coat. One must keep all the shedding undercoat brushed totally out or you do not allow air circulation at the skin. And after 22 years of pet grooming, people do NOT brush their dogs properly at home. (the ones coming to the groomers anyway)

Shaving the hair off a dog should not affect the coat. If the dog is healthy it should grow back according to the dog's DNA. Out of thousands and thousands of customers who have had their double coated dogs shaved I have seen only a handful who did not grow back properly, and of those, most ended up finding a thyroid or other metobolic problem.

And 99.7% of the people who have had their dogs shaved (the ones that crossed my path over the last 22 years) never go back to the full coat. Stories of how much more content the dogs are, are told often.

I am not a vet, only a groomer. My experience only comes from my customers. Take it for what it is worth.