Obviously this thread has taken to a lighter side, but on an even quirky side line - I bet even if you cut the tail off, they would still get the syptoms, you just wouldn't see it as readily. It is my understanding that cold tail is caused by over exhaustion of the muscles in the base of the tail, sort of like delayed muscle soreness in humans. So those muscles would still be there, unless you amputated the entire posterior of the dog?!?!?!
I just realized how ridiculous this might sound but figured if I save one labs a**, its worth my ridicule.