Hello group. Thank you for accepting me. I hope that I don't leave any important details out in this post as I'm trying to give as much information as possible in order to solicit ANY advice you may have. One year ago December, my boyfriend moved in with me with his female ACD/Pit Bull mix female, Eva. He says that her father is "purebred" Pit Bull and her mother was 1/2 Pit Bull, 1/2 ACD. He got her from a friend who had an "accidental" litter when she was around 8-9 weeks old. Because he worked a lot and was not home, she was left to fend for herself for long periods of time almost immediately. For most of the time from her birth (sometime in March of 2011) until coming to my home in December of 2012, she lived in her crate with very little interaction. Devastating. She had experienced pretty much NO socialization with other dogs, and little socialization with humans. She came into my home and I had never had dogs before. She and I very quickly bonded and she seems to be more bonded to me than she is to the boyfriend as I am the one that feeds her, plays with her, walks her, lets her outside, etc. Things went rather well and she learned some basic commands. She is an extremely affectionate dog. I will be the first to admit that there has not been an overabundance of discipline in her life. She is allowed on furniture, laps, and has been allowed to stand up to greet us. She is what I have called, a "nervous pee-er". When someone comes to visit that she doesn't know, she urinates a small amount on the floor when she greets them. Otherwise, she is completely housetrained. In September, a dog came in to the shelter that I volunteer for. Nana is a 3 year old St. Bernard. She was spayed upon coming in to the shelter. I fell in love with her. She knew and obeyed many commands, was extremely calm and gentle. I brought her home a few times to see how she and Eva would interact. They did quite well with eachother. There was a lot of excitement and a lot of play. After several times of Nana "visiting" the home and interacting with Eva without incident, I made the decision to adopt Nana. In the beginning (and up until possibly a month ago), Nana eas extremely respectful of Eva. She wouldn't attempt to take a toy from Eva, she would just walk away and relax. The only problem that we did have with her immediately was interaction with our cat, Dexter. We have two cats. We have an extremely confident 6-7 year old neutered male that very much enjoys the dogs and prefers to be near them, Malik. Dexter, a neutered 3 year old male, acts a lot like a prey animal. He runs from the dogs, which incites Nana to want to chase him. She would get fixated on his actions. She never did anything that scared me, but her chasing after him made me nervous. Her fixation is sometimes hard to break, though it has improved. There have been three incidents between Eva and Nana in the last month or two. The first incident was play that became too rough. Eva's head hit one of Nana's teeth and she had a wound above her eye as a result. The next incident involved resource guarding. Eva was chewing a nylabone and Nana was a few feet away staring at her. I sensed that this was not a good thing and attempted to redirect Nana's focus, but Eva lunged at her and the two of them engaged eachother. I was alone in the room and grabbed each of them by their choker collars. I separated them, but Eva pulled out of her collar and came back toward Nana, instead grabbing my arm. My boyfriend came in a few seconds later and got them separated. I didn't require any stitches and I truly feel that she had no idea she had bitten me. Neither of the dogs sustained any injuries from this. Yesterday, I made the mistake of giving them each a chew toy. It quickly escalated and Eva lunged at Nana. The two were extremely hard to separate. Nana ended up with a laceration on her lip and Eva with a few wounds on her muzzle. Today, their behavior was without incident until my daughter and I returned home and were putting groceries away. Oh, I should mention, they are both crated when we are not home. As we were putting groceries away, both dogs were in the kitchen. There were no resources to protect. Suddenly, they were again fighting. No injuries resulted and I was able to pull Nana away, my daughter grabbed Eva...When Nana is pulled away, she stops. Eva doesn't seem to know when to stop. She still attempts to keep coming. I appreciate any advice and can accept criticism. I am not an experienced dog owner. I would like to educate myself and become the best that I can be for these dogs.