the first thing i want to point out is that shaving a dog like a poodle, maltese, schnauzer, etc, is completely different from shaving a dog like a b/c, aussie, chow, pyr, etc. they have completely different hair types. if you shave a poodle, the hair will grow back the same. poodles, etc, do not use their coat as much for temp control. a dog with undercoat, needs his coat for keeping cool and for keeping warm. the ONLY reason a dog would be too hot in full coat is if the undercoat is not removed properly.
when shaving a doublecoated breed, you will mess with the regrowth of the coat. undercoat grows much faster than the guard hairs, and for at least 6 months to a year, you will have a fully cottony mess. without the gaurd hairs, the undercoat alone will mat up much easier than regular hair (so that means a shaved dog needs to be brushed even more). most dogs do eventually grow back, but dfuring the time they are growing in, the dog is at an extreme risk of the elements, whether its cold or hot (this is pretty serious, considering these dogs spend their whole lives with that coat, some do have adverse reactions to suddenly having nothing there). Also, if your dog has an unknown health issue, the hair may never grow back (i have seen this happen to many dogs, when if the issue had been found before the owner decided to shave, the coat could have been saved.)
i know many of you have psted that your own dog was shaved and had never been happier. all that really tells me is that the coat before the shaving was just not being properly cared for. i know many dogs, working in grooming and daycare, and know plenty of doublecoated breeds whose owners keep up with the undercoat, and those dogs do completely fine in the heat (and i live in southern california, its november and we just hit 95 this last weekend).
some people have brought up that it is better to shave your dog than have a matted dog. well if the dog was a poodle i agree. but most (not all) of the time, i have been suddessful and brushing out a matted double coated breed. usually it is dead hair that matted, and its comes out very easily b/c it isnt attached to the skin anymore. most experianced groomers are able to do it without causing any discomfort to the dog.
some have also mentioned that someone should get anydog without much consideration for hairtype. that is a huge mistake. why would you get a golden retriever when you hate dog hair? or a chow for that matter? i personally think it is a little selfish to get a dog with hair and then for your own satisfaction shave that dog b/c you cant handle the hair for whatever reason. most of those reasons arent even valid: shedding- does not stop shedding, only littler hairs, that actually stick to everything instead of just falling on the floor, will appear; cool- already explained the myth of these one; matting/upkeep-also already explained how haveing a shaved dog is actually more work than having one in full coat.
if i sit there and explain to an owner all the possible things that could go wrong with having their dog shaved, and they still want to do it, then that really tells me what kind of person im dealing with. i understand that some do not see the seriousness in some of tthe issues explained, but why would you want the possibility of causing your dog any discomfort just b/c you cant deal with his hair? i just find that to be very selfish on the owners part.
and, yes it can be a matter of life and death. many dogs have suffered adverse affects, and i have heard of dogs dieing of heat stroke after being shaved.