My vet recommended that we neuter our 6 year old German Shepherd for an ongoing prostrate problem he was having. We decided to have our other three year old german shepherd done also. In no time they both seemed to have dry, lusterless coats. I have had to give them skin pills ever since. Nothing had changed in their diets and their coats almost 2 years later still don't look as good as pre-neutered. Is this Normal?