How to stop my neutered cat from attacking the neighbor's cat?

Neutering male cats is one of the most effective ways of limiting inter-cat aggression. There are no guarantees, but castration is definitely the first and best thing worth trying. If you are worried about the two cats hurting one another, I would keep them separated for the time being. Even after the castration there will still be some residual hormones left in the body for a short while. I would consider keeping the two separated for at least a week or two post-operatively before reintroduction. Hope this makes sense.

Thank you for using Petco Pet Education Center, formerly Petcoach! I'm sorry to hear Vanilla has been having issues with another cat. While neutering may help improve the problem, it may not resolve it completely, especially if the other cat is neutered. As you mentioned, ideally Vanilla would be an indoor only cat to ensure that he doesn't get into any fights, and his desire to roam may lessen with neutering as well. I would recommend he be neutered, and you try your best to keep him inside as much as you can to eliminate the possibility of a fight. Good luck!

Neutering will help him from running off and fighting. It will unlikely stop him from fighting to protect where he lives and his food. He should be tested for feline leukemia and aids though as this can be a fatal disease and he may continue to spread it if he keeps fighting. The other cat likely will need to be caught, neutered and released to minimize the behaviour

Unfortunately it’s very difficult to train cats. Unlike dogs, most of them do not have a desire to please their humans. Other than just be extra cautious when leaving the house so that he does not slip through an open door, you can purchase electric fence type devices for the house. Roxzy, would wear a special collar that will give a static correction if he approaches the boundary. Meanwhile you would set up the boundary around the door. Most cats respond very well to this system. I hope this is helpful and please feel free to post any additional questions.

That is unusual behavior so he may be irritable from being in pain. Outdoor unneutered male cats often fight and he may have an injury you can’t see which is painful. I recommend confining him to another room until he calms down so no one else gets injured, and see if he is eating normally. If this behavior continues please take him in for an exam to check for a wound or area of pain. In addition I would consider neutering him also. Neutered male cats seldom fight, they are more docile and less aggressive. Thanks for using Petco Pet Education Center, formerly Petcoach to help you care for Timmy.

Hi. Yes, neutering will help Toby want to stay home more and hopefully make him less likely to fight. It can take a couple of months after the surgery for his testosterone levels to completely drop but neutering typically does resolve a lot of male to male aggression in cats.

It can take several weeks for testosterone levels to decrease after neutering. Until then, consider using a pheromone product, such as Feliway spray or plug in diffuser, to decrease any anxiety or aggression in the home. Provide extra litter boxes, bowls, toys and bedding to prevent food aggression or resource protection.