Why do my spayed/neutered dogs fight? How to stop their aggression?

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!

Neutering can sometimes help with interdog aggression, so if you plan on keeping them both, having them neutered may help. If they are constantly fighting with each other, it may also be time to bring in a professional who can view the situation in person and help formulate a training plan to get the dogs OK around each other. You may need to keep them completely separated and slowly introduce them in a neutral location such as on a walk, and then only have short monitored sessions until they can be trusted around each other. However, if one dog is lunging and growling before even being introduced, seeking professional help is best.

If they are not spayed then you should start with that. Hormones can certainly cause aggression. After the surgery it takes about 30 days for the hormone levels to decrease to a level that may change aggressive behavior. If that does not help then you should consult with a professional in-home dog trainer to help you sort out the root of the problem. I see you are in Puerto Rico. There is a HUGE free spay/neuter campaign coming there in November. I suggest you check it out if you want to get your dogs spayed. Search "Spayathon for Puerto Rico" on Facebook to find their page. Hope this helps. Best wishes.

Hi there. Actually, yes! To reasons not always know to us-changes in the hormonal makeup of our animals (i.e. a recent neuter) can make them smell different. Many theories have been postulated as to why previously accepting partners will turn away the new "smell" and show aggression. Many think it is frustration in the change. Some think it is because they now want to show dominance. Often, we do not ever really know for sure. Normally with time the pair will acclimate again, but I usually recommend supervised playtime until then. I hope this helps!

When you have two bitches together, they will show aggression to compete for territory and intact males especially if they are in heat. The best thing to do is to have both of them spayed. This will reduce the aggression between them as it is most likely hormonally related. It will also eliminate the risk of a pyometra, which is a life threatening infection of the uterus. Without spaying them, you will have a very hard time reducing the aggression because it's hormonally related. Removing the source of the hormones is the best way to stop the aggression.

Yes, having them fixed can help reduce aggression as dogs fight over territory and females. I would definitely have them both fixed, and I would also recommend professional behavioral training for them both when they are fixed. This can help with the aggressive behaviors, and I recommend using a professional because training aggressive dogs can be dangerous. I never suggest owners do it on their own for safety reasons. First step is to get them fixed, and I would have that done asap.

Unfortunately it's impossible to know without being able to observe the dogs. Certainly if both males are not neutered, that could be a big reason. Typically, intact males are more prone to fighting. It's possible now that the Bulldog is 2, he is now officially an adult and could be competition to the older male. That's just a guess. 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.