Boxer Jealousy?

Question
We have taken our 1 year old boxer to our friend's cabin twice now. She knows our friend's lab well and gets along with him very well, but each time we've had other friends show up with another dog later (one time it was a golden doodle and most recently a golden retriever). At this point our boxer starts to fiercely go after the 3rd dog without being provoked. I'm wondering if this is a jealousy issue? Our dog is otherwise very sweet around all humans and will only get aggressive around other dogs if she's provoked. Please let me know your thoughts on how we can help our dog to be more calm in the above situation.

Thanks for any assistance,

Kav

Answer
You said that your Boxer get along with your friend's Lab well, but not the other dog that show up, right?

It is a jealously thing, and a protective mode as well.

Your dog has made friends with the Lab and does not want to share his friendship and thinks the 3rd dog is a threat to the pack-- and the Boxer is displaying the Alpha position.

The only thing you can do is try behavior modification.

I always recommend buying and using a whistle.

Each time your Boxer displays aggression toward a 3rd dog, blow the whistle and verbally reprimand her. Leash her, and hold her on the leash for a time-out for 5-10 minutes.

Do this each and every time.

Be consistent.

Soon, she will associate the aggressive behavior to the reprimand and stop.

Let me know in a few weeks how it worked and go from there.