Aggressive towards one dog in particular
When Gunnar was about 16 weeks old I took him to my dads house to see his 6 year old high energy lab. The lab liked to tease Gunnar by running close then away. Sort of like a jet plane buzzing the tower. Gunnnar would give chase but was slow in comparison and the lab would buzz back by and trip Gunnar up every now and then. Admittedly not a good interaction, but the lab plays with all dogs like this and she's part of the family so I figured we'd have to learn to deal with it.
A few weeks later we went back to dads, and by this time Gunnar was in a stage of barking at other dogs. Most likely a fear response. Well he barked at the lab for a good hour strait. I eventually had to crate him in the basement while my family was at dads house. I could not curb the barking no matter what distractions I tried. It took an aggressive correction to end it that day. After the correction the barking ended if I kept the dogs out of sight of each other.
Step forward to Gunnar at 4 months old. He was now large enough to play chase and keep up with the lab. When chase ended they played and wrestled and then left each other be. I figured they had "worked it out" and would be okay to hang out together. That day ended well.
Step forward to 6 months, Gunnar is now 60#s and stands as big as the lab. He's faster on the ground and has more endurance. We let the dogs play ball together, but it turned into wrestling and then the lab got tired and went from play to panic mode. Basically a dog fight, but no blood and Gunnar wasn't being mean, just playing rough and he lab couldn't get away.
So now, we are a few weeks past the fight and I took Gunnar to dads again. I can't let him off leash near the lab as he seems to want that rough play that lead to fighting. He barks and pulls at the end of the leash and won't come under my voice command no matter what corrections I dish out. I need these dogs to get along. I spend a fair bit of time with my dad and we both like to take our dogs everywhere.
I was watching an episode of Caesar Millans leader of the pack and he had a shepherd that he introduced to an older dog and he made the interaction so that the shepherd looked to the older dog as being dominant. I think this would be the best situation for dad and I, to have his lab be seen as dominant by Gunnar. How do I go about facilitating this?