Why is my new pitbull aggressive? Is it Deramaxx or his leg pain?

Yes, she might be more protecive since her puppy is around. You can try an Adaptil collar and Solliquin chews and see if that helps with any stress/anxiety. You could also take her to a trainer or behaviorist but if she is biting your friends then you may need to confine her when friends come over.

I'm so sorry you are having this problem. It does not sound like Duke is being aggressive (and as you noted he gets along great with your other Pit). The problem is that it sounds like your Pomeranian finally frustrated Duke enough with his behavior of growling and barking that Duke finally had enough. As you said, the problem is that your Pomeranian is so small. So, although I would not be worried that Duke is aggressive, I would be worried that your Pomeranian could easily get himself hurt again. Unfortunately, I think I would keep your Pomeranian away from Duke. It is too easy for a dog that small to get hurt by 2 larger dogs. I hope that helps. Good luck!

There are lots of possible causes, but the most important one could be pain. I would consult with your vet and make sure her pain medications are all at the best doses for her currently. Alternatively, she could be developing some resource guarding. She has gone through a stressful procedure and she may be feeling more sensitive and protective of herself and her spaces. For now, I would keep the puppy away so he doesn’t get hurt. This article may provide more insight: https://veterinarypartner.vin.com/default.aspx?pid=19239&catId=102897&id=10464193

Pain can cause aggression in dogs (and people!). He is obviously in pain and I strongly recommend you take him to a veterinarian for an exam. The vet will put a muzzle on him so he can examine him. Your dog will need at least pain medicine. So please take your little shark to the vet tomorrow. It may be easier to just close his crate and take him in the crate, so you do not have to make him walk.

Many times when dogs get older they get arthritis and they hurt so that is why they get grumpy. I suggest you have her to your vet for an exam. If she has pain somewhere the vet can prescribe medications to make her feel better.

Since this is so out of character for him he certainly could be injured. If a dog is hurting in a specific spot, they will sometimes becomes hypersensitive in that area. They will sometimes become aggressive. I would have your vet take a look at him. Your vet will be able to localize the pain and start him on pain meds if needed. You may also have to put him in a short course of anti-anxiety meds until he feels better. Your vet will also be able to do X-rays if needed. I hope this helps!

The answer very much depends on why he's aggressive (fear-based, territorial, play-based, etc) but my general recommendations are to stop ALL punishments, avoid anything that is causing aggression, and never allow him around children. Then you need to find a veterinary behaviorist to work with who can go over a detailed history and diagnosis and treat his issues. If you are unable to find a veterinary behaviorist, your vet may be able to start him on medications and talk about some behavior modification.