Dog Park Aggression

Question
A month ago i adopted a 2 year old boxer from a rescue i volunteer for.  I have owned boxers for years, but am looking for some advice to conquer a problem i can't quite get through.  Not that much is known of Dempsey's history.  He was bought from a breeder by his prior owners, they starved and abused him profusely before finally surrendering him to our rescue.  He was my families foster dog before i decided to adopt him and take him out to Indiana with me when i went back to college.  Because he needs energy i bought a membership to our town's 5 acre private dog park.  I take him there every day.

Occasionally he will get aggressive at the park.  He is VERY vocal when playing and this can cause problems at the park.  Almost all the dogs are extremely friendly but Dempsey doesn't see to fit in as well.  He is very friendly, loves people, and gets along with dogs but plays rough.  In our foster home he played great with our dogs because he lived with them and adjusted to them.  But he has become aggressive at the dog park.  He won't really play with other dogs, when he runs with them he will lunge at them and growl, and they will go back at him.  He is not one to back down and this creates a problem with a lot of the dogs.  How can i get him out of his behavior? I try to call him off other dogs but his training goes out the window when at the park.  I don't think he was ever trained a a puppy and i have him in a basic obedience class right now.  Some times he is at the park and plays fine, but some days he becomes a brute and i get those looks from other dog owners.  I don't want his behavior to become a repetitive problem and then he wont have a place to run free and get his energy out.  Any advice?

Answer
Hi Lindsey...

My advice to you would be to skip the dog park for now.  It's a good idea and I understand why you want to take him, but, unfortunately, he's not ready.

Socialize him profusely, on lead, before you put him in this type of situation.  Get through your obedience class and then advance to the higher level.  Instead of taking him to the dog park, take him to calmer places where he can meet dogs...the pet store, friends' houses, family's houses, etc.  Let him play with dogs one on one before you get him into a group setting.  Once he's learned manners and how he's expected to behave, you shouldn't have this problem.

On the flip side, if you continue your jaunts to the park, he's going to keep at this current behavior and it will become learned.  Breaking it now will be much easier.  You're fairly new to him and he's not confident in you as a leader at this point.  He has no reason to listen to you.  After you've had him a while, and you've gone through classes and practice sessions at home, he'll begin to look to you for guidance.  THEN you can start to introduce him to a group setting like a dog park.

You may have had Boxers for years but as you're seeing, an abused dog, and behaviorally challenged dogs, are different.  :)  You're moving too quickly with him...slow way down.

You are at the very least his 4th home.  You're new...the town is new...the house is new...let him get used to things and settle in.  It's a really common mistake to move quickly with a new dog because of the excitement they come with.  :)

If I can help you any further please let me know.