Min Pin won't eat.

My 2 year old (obese) miniature pinscher has been displaying very odd behavior. Initially, she stopped and/or significantly decreased her food intake, when she normally ate everything in sight. Now, she is having accidents in the house at night, when she has been potty trained for some time now. She is also showing increased aggression, doesn't seem to like playing very much anymore, and tends to isolate herself from the other dog(s) when she was normally reasonably sociable. She even bite me (not very hard) when I tried to move her the other day, which she has NEVER done before. Otherwise, nothing else has changed. She's had regular firm bowel movements and normal urination, does not appear in any pain, has normal energy levels, no vomiting or diarrhea, has not ingested anything that might be causing obstruction, her teeth are in excellent shape, and her gums are nice and pink. I took her to the vet after a few days of not eating at all; she wasn't even interested in human foods. The vet ran several tests including blood work, which showed no problems at all. Her liver enzymes were normal as I worried it could be possible liver disease, no signs of infections, or anything else. His advice was to treat her as though she is a picky eater, since all the tests came back normal. He gave her a b12 shot to stimulate her appetite which didnt help. Before that, he had prescribed her a can of high salt, high fat food- called LD to see if she'd eat it but she didn't. This has been going on for almost 2 weeks. Okay, so her environment has changed. One of our dogs passed away suddenly and unexpected from a seizure with an unknown cause. The dog in question - Daisy- witnessed the other dogs' seizure and my subsequent panic and sadness. This is when the appetite change began. Several days later, we brought home a 3 month old male puppy. She does not particularly like him and he is not yet potty trained although making great progress. She snaps and growls at him, and has no interest in playing with him. We have another female dog in the home - who I'd guess is the alpha dog, who she doesn't play with anymore either. The vet also suggested a DAP pheromone diffuser in case her problem could possibly be depression. I purchased one off the Internet and it will arrive in a few days. I have normally fed Daisy dry Purina One dog food which she never had a problem eating. When she did start getting bored with it, I would mix her dry food with dog gravy or a little bit of people foods that are non toxic for dogs but only once in a while. But, after the recent long bouts (2+ days) of her not eating at all or very little, I would offer her people food. She was no longer interested in healthy food she'd normally love, such as chicken, carrots, white rice, lean pork, etc. and would only eat high fat foods like sausage and cheese, which I only gave her because I felt she had to eat something. Initially, I tried wet food, but she had no interest in that either. After the vet visit, she is still not eating much. She has eaten chicken and will eat a fair amount of wet food IF I hand feed it to her (yes, it's horrible-I've gotten to the point where I have to hand feed my dog to get her to eat!). She will eat treats and Chewies but is very selective as to which she will eat and will hide them under the covers and growls at anyone who even thinks about coming near them for a while before she will either eat them or forget about them. She was always a huge treat fan! Any ideas as to what might be going on?? Is this a behavior problem? Her reaction to Stress or depression? Boredom? Territorial behavior? Her assertion as pack leader? An illness we haven't uncovered yet? Or what!? What should I do?

Thank you for your timely response.

I forgot to mention that Daisy has a luxating patella on her back left leg. The vet says its most likely at a grade 4 as you can pop it back into place but it just gets out of whack again. She's had pain and inflammation medicine prescribed previously but is no longer on anything. I try to give her glucosamine, but she won't take it right now. The vet manipulated her leg and insists she is not experiencing any pain. I had considered this as a cause because she has trouble jumping up on the bed/couch now and walks funny. I gave her a dog aspirin before I took her to the vet hoping that would relieve any pain she might be feeling and get her to eat but it didn't improve her appetite.

Before this happened, the vet suggested getting her thyroid checked out with a T4 and he prescribed her weight management food. I didn't get it for her because of the expense and because she stopped eating all together. I had never had her thyroid checked because her other vet said what you did - it's highly unlikely she has thyroid issues at 2 years old.

Although hypothyroidism is certainly possible, currently, Daisy is not showing symptoms. Her coat is nice and shiny, not brittle at all and there is no hair loss. She doesn't have intolerance to cold, nor is she lethargic at all. She hasn't had any weight gain. She's lost about 2-3 lbs on her last vet visit - this past Tuesday- and has probably lost more since. But anything is possible.

I will try the behavioral approach you suggested. I am only offering her usual dry food exclusively and putting it away if she doesn't eat within a time frame as she used to. She hasn't eaten anything today at all. How long can Daisy go without eating anything? How long can she go eating only one or two bites of food a day? She is drinking water normally, and I have set out water with a little chicken broth to help get some calories into her. I didn't start offering human food until she ate very little for 3-4 days. The vet said something can happen to a dog after 2-3 days, but I can't remember what he said about that - I think it was something about lipids, perhaps.

If this doesn't work after several days, I will talk to my vet about anti-anxiety medication. Hopefully the DAP pheromone will help.

Thanks again.