aggression issue

[ladybugtastic]

It's been quite a while since I've been to this site, but I've recently come across an issue that I'm having with my two dogs. I have a 2 year old German Shepherd mix. He does have aggression issues and while he has had them for quite a while, my husband and I have seen a LOT of improvement in him in the past few months. the degree of his food/toy/chew guarding has gone down significantly. We also have an 11 month old pit bull mix. She has a SUPER sweet personality, and we started working with her right after we got her on aggression. (I can pet her mouth while she's chewing on a rawhide with complete confidence that I'll still have fingers afterwards.) My problem is, just recently -like, within the last week- my pit bull has suddenly started attacking other dogs. we've been taking her to a play and train class with our dog trainer, which mostly let's the dogs all run around and play with each other in a controlled environment. She's always done really well around other dogs, and quickly adapts to how other dogs are playing.

Last Saturday, we took her to this class to play, and she did really well until we pulled out some tennis balls. As soon as another dog got near the ball she was playing with, she viciously attacked. she never drew blood, or even put her mouth on the other dog, but her hackles went up and she immediately just started going after that dog. We immediately picked up the balls and put them away, and she went back to being her usual sweet self. We hadn't really seen any more episodes with her until today. I had both of my dogs sitting there, and I've done this quite frequently in the past, but I make each of them do a trick/command, and then they get a treat while they're sitting side by side. I had my older dog do a trick and started to give him his treat when the pit bull suddenly went after him. after that point, I took her leash, which is almost always attached to her while she's inside, and hooked it on a door across the room, then went back to my other dog and continued what I was doing. after I was completely done with him, and cleaned up my mess, I finally went back to my pit bull and made her sit and stay sitting while I unhooked her leash and let her play a bit more.

Sorry about the long post, but I was wondering if anyone could give me any suggestions on how I should approach this issue? I just want to be able to get my point across to the puppy that this behavior isn't okay, but make sure that I'm not correcting my other dog for something he didn't start.

[Sabrina]

Hi! I'm mostly just bumping this thread so it doesn't get missed, but I did have a few questions:

and she did really well until we pulled out some tennis balls.

Had there been balls to play with at previous classes? Was she leashed at the time? Could she have attacked the other dog (eg not physically restrained)? If she could have attacked but didn't, it sounds like she was warning the other dog that the ball was hers.

Could you explain what exactly happens at a typical "play class"?

I had my older dog do a trick and started to give him his treat when the pit bull suddenly went after him.

Did she make contact?

after I was completely done with him, and cleaned up my mess,

"Mess" - did something get spilled?

If you could include a run-down of your dog's typical day, that would help people get a better idea of life from your dogs' point of view. Also, when were your dogs last checked by a vet? Do either of them have health issues?

Until someone who really understands multiple dog households (I only have one dog) and/or puppy development comes along, I think I'd try training them separately (out of sight/earshot/access of each other) so there is no chance of them trying to compete for resources (treats, attention, etc).