coat

Question
My shepherd loves to swim. I live in the Colorado Rockie's and the water is very cold. Someone told me the other day that cold water is not good for their coat. Is this true. What do you think about him swimming in cold water? Also he has not grew his undercoat for a couple of years. I moved from Ohio where winters are mild. Do you think he will grow it this winter. I live at 9000 ft. and winter should be cold and snowy. I know when I lived in Buffalo he always had an undercoat. One more question. He is a five and half year old male. 100lbs great dog. So loving and obedient, always wants to play and when not playing wants to snuggle. He is a big baby, until my landlord brings his three dogs over. Well he is good until the older male comes near his dog dish, then he gets riled up. Does not bite him, but definitely threatens him. Sometimes with his ball as well. he is not fixed. Do you think as he gets older he may get even more aggressive behavior around his food. He lets my other dog eat his food. Of course my shepherd was brought up by this other dog who is 3 years older. If I get him fixed could his personality change. I love how he is now. He loves everybody, kids, adults, strangers. The only time he is like this is with this other fixed male near his food. Is there any benefit to him being fixed? I have heard the older some shepherds get the more unpredictable they get. Thanks patrick

Answer
Neither question is playing to my best experience and training.  I am wondering if he is a little older now and spending enough more time inside, or it is is a different environment that he is in too much to develop the under coat.  If he enjoys the cold swims, I don't think they hurt.  I have been trying to keep my old Lab out of cold water ever since she caught pneumonia a couple of years ago at 12.  

I am not sure the neutering would help the food dish thing.  Otherwise, it shouldn't change his personality.  One large, definite factor is the chances of cancer in a few more years.  Getting the dog neutered can greatly reduce its chances of getting cancer in later life.