Expert: Jill Connor, Ph.D. - 10/16/2008

Question
"I have an Australian Shepherd. He is almost 6yrs old. He was recently sick with skin allergies. My bet had him on antibiotics for 20 days and I changed his food to Wellness core. Recently he has started to growl a lot. I'm not sure why, if he still not feeling well, doesn't want to be bothered, or showing dominance. If he is sleeping on the bedroom floor and I walk in he will growl at me. My husband goes to sleep early because he gets up at 3:30am. The dog usually joins him. If he doesn't want to move, he growls at me.  If my husband is holding him, petting him and I walk up he will growl at me. Today he was eating his bone and I came over and he growled at me. He has never been this way before. This is all something new and I'm getting a little concerned. I've never had problems in the past with this. Also, i could always walk up and take a bone/ toy away from him. Any ideas?"  

Answer
Any change in behavior can be an indication of illness.  Skin ailments are very difficult to diagnose for cause and can be an indication of other problems.  I don't know what food you were feeding.  Wellness has a "Simple Food Solutions" formula that is supposed to address allergic response; whether or not it does I have no idea.  If your dog presented with a rash, it should have been scraped and looked at under a microscope.  I assume your vet did that; I have no idea what antibiotic your dog was on, but 20 days is a very long course of treatment.  Your dog may not feel well, and this may be why he is exhibiting this aggression.  From your description, however, the dog appears to be guarding your husband (or trophying his presence).  It's impossible for me to diagnose cause of this behavior from your description of it, especially given the dog's medical problem.  You need the intervention of a certified applied animal behaviorist (NOT a dog trainer.)  Contact the veterinary college in your geographical area for a referral to someone within reasonable driving distance.  Compare the label of this Wellness product with the ingredients of the dog's former food; talk to your veterinarian about introducing a prescription diet and get a second opinion regarding the dog's skin condition.  Meanwhile, remove the dog from the bedroom ASAP.  Give him his own sleeping space with a comfortable bed (possibly the kitchen.)  Instruct your husband to IMMEDIATELY WALK AWAY from the dog if it should show any aggression toward you while in his presence.  Put a short, lightweight leash on this dog and MOVE HIM out of your way, using ONLY THE LEASH.  Do NOT confront any aggression, you will be hurt.  Find a professional as soon as possible to determine behavioral cause of this problem and assist you in correcting it.