Why is my spayed young dog suddenly aggressive to my older dog?

Hi and thank you for using Petco Pet Education Center, formerly Petcoach! I am so sorry that your two pups have not been getting along recently. I would separate both dogs while you are away until you can figure out the issue. A lot of times housemates will fight due to phobias (thunderstorms, loud noises), separation anxiety or aggression. Also, sometimes one dog may have a medical issue presenting it self to be weaker than the other dog. I would make sure both pets are pain free and have no concerning issues like vomiting, diarrhea, weakness, pain etc. A lot of the time, the newer dog in the household tends to be the aggressor. I would work with each dog separately and together for obedience training. If possible, i would get a professional dog trainer to help. A lot of the time it is the people that need training on how to properly time commands for their pups. Once they have a solid foundation of obedience training I would try a few things that will test ability to ignore one another in the same room, then give one dog attention while the other one ignores it etc. I would reward the dogs for remaining calm. This will help teach them that they can be in the same space and tolerate each other. These can be some helpful training tools that you can start with. However, if the fighting escalates, getting a professional trainer would be highly recommended sooner rather than later! I would really appreciate if you could mark this question as helpful or not as helpful. It allows us to improve on the quality of our answers to other pet owners!

It is probably a territorial/hormonal problem which could be resolved eventually by spaying her. Try to observe them and see when that happen and try to avoid the situation ( for example over food = feed them separately and so on).

Sometimes dogs don't like the change in smell when another dog comes back from the vet. You may want to wipe down the older dog with a damp cloth and brush her to get the vet smell off her. It also can be that he now sees she is weak and he wants to take over being the top dog. This can be dangerous as he could fight with her and hurt her so you are right to keep them separate when you are not there to monitor their behavior. If your younger dog is well trained I would make it clear to him that this is inappropriate behavior by your voice and placing him in a crate or outside when he exhibits this behavior. Hopefully in a few days things will settle back into the normal routine. Thanks for using Petco Pet Education Center, formerly Petcoach to help you get answers to your veterinary questions.

Thank you for contacting Petco Pet Education Center, formerly Petcoach with your question. No, this isn't normal behavior after spaying, and spaying doesn't cause aggression. It could be Clementine saw something at the vet that upset her, and she redirected her aggression at your other dog when she got home. I'd keep an eye on her for now, and if this behavior continues, I'd take her back into the vet. Best of luck.

If this is real aggression, you may need to separate them until after the heat cycle and hope for the best. Sometimes problems can persist beyond that. Typically, households with altered dogs will have a lot less conflict than households with intact dogs. There are many benefits to spaying and neutering and I recommend to discuss this with your veterinarian: https://www.petcoach.co/article/spaying-ovariohysterectomy-the-benefits-in-dogs/ Canine aggression is a complex behavior as it can stem from dominance, possessiveness, fear, anxiety, resource guarding or a combination. Most people are not familiar with reading canine body language and training. Because of this, I recommend to work with a professional trainer. Researching on your own will also be helpful. Familiarizing yourself with canine body language and dog training can help you to recognize what your pet is trying to say. You can find many books written on the topic and there is a trainer named Victoria Stilwell who I think is particularly helpful. Best of luck.

Hi and thanks for using Petco Pet Education Center, formerly Petcoach! Sorry to hear about Mylah and her apparent aggression. Aggression problems can be very complicated and complex. One thing you should do initially is take her to your veterinarian and let them make sure that she is healthy and that nothing appears wrong medically. Pain, etc can bring about aggression and irritability problems. Once the medical check is cleared, then you can discuss with your vet exactly what is going on behaviorally. Your veterinarian may want to refer you to a certified trainer or animal behaviorist to try to sort out what is triggering the aggression. I see she is spayed so we can rule out irritability/aggression associated with her heat cycles. I wish you the best of luck with little cutie Mylah.

How long ago was it when she was spayed? If it was very recent, is she on pain meds? If not then I would recommend discussing this with your veterinarian and see if they can put her on some type of pain medication. If it wasn't within the last week then it most likely has nothing to do with pain related to the spay and there may be something more going on which would require a vet visit and potentially a trainer. Thank you for using Petco Pet Education Center, formerly Petcoach.