Can a dog (male puppy) favor Dad over Mom?

There are a number of reasons why Loogie ( sorry but that is an awful name for a beloved dog it reminds me of "Hucking a Loogie" ick) treats your girlfriend differently.  But let's begin with the basics... The peeing incident  just because she saw the pup pee infront of her does NOT mean he didn't need to go out again later. Puppies have less control for many reason including smaller bodies for holding it and less practice.  Until he has it 100% perfect he needs to be on a schedule. Is it a pain? yeah sometimes it is, but it is still an honest truth. He may have stared at her the entire time he urinated but it was not a "Take this B***H" it was a "Stop yelling at me if you had been watching me you would have seen I was in need of going out" glare. The very old school rubbing their nose in a potty mistake works about as well as throwing pies at a wall. It makes zero sense to them, they potty and walk away from it. It is forgotten in minutes. You getting mad and yelling or then getting physical with them just makes them lose trust and respect for you. Dogs , no matter how dearly we love them do not relate to us as another dog..  Just as they don't suddenly think you are "Mom and Dad"  They will idenify you by these names because that is what YOU call each other.  You could be Chair and Sofa if you called each other that often enough.  Chances are really good your girlfriend speaks to the pup in a higher register.  Some dogs can learn to accept the shrill notes but many ,especially bright herding breeds find them both annoying and lacking in confidence.  The Herding Breeds aren't looking to you to be their parent or their Alpha. They want and need a JOB that has predictable requiements and boundries.  If the pup is messing in areas you do not walk in , behind a chair or in a side room. They are simply  relieving themselves because they don't have clear signals established between the two of you. My dogs , all  5 know to go to the door and knock.  Many dogs are trained to hit a bell that hangs from the door handle etc if you don't have a signal established you need to stck to a strick schedule. They may not potty each time But if when they potty you use a command like " Pick a Spot" or "Do your Business" and repeat it while the dog potties in a strong positive voice, then the next time you go out you watch their body language and as they begin thinking about going you give the command, then again repeat it when they go. Soon you have a dog that understands you want them to relieve themself when you reach the potty area you have choisen for them. My hounds potty on lead and off, they know to go on command as when you travel a show circut it is necessary to have a system that works when needing to walk 5 or more dogs.  If you think that loving your cute puppy and feeding it should be enough to have a well trained dog you will be in for a huge let down. Dogs need schedules and consistant expectations. 

We have been in our breed for over 30 years.  I have 5   2 week old puppies right now, they will not go to their new homes before 10 weeks old and at that time they will be 90% housebroken, crate trained , leash trained, and have a decent recall.  It takes massive amounts of training for this to happen but this is why my puppies are in a huge demand for my breed. From their first breath on we work towards a goal of the pup being well trained and intelligent to assure every placement will succeed.  We teach our puppy folks to Train not Complain. We don't mind emails, yexts and phone calls as long as the person reaching out is focused on understanding the goals they are working towards. Becoming frustrated or angry is a waste of energy. It shuts down the communication with the dog and yourself.  Taking your ego out of it and not thinking the dog is messing in the house to get even with me is a huge first step.  From your note and the ones I have seen from your giurlfriend I would hazzard an educated guess that she begins to get a desired result then turns it in to a short cut when she should be re enforcing the desired behavior and reactions.  Loving a dog is critical but it is best shown by training it so it will have a successful life with it's human.

Technically, a dog, or any animal, including human, can prefer one person to  another. Just think,  you probably prefer some people over others, and I bet you even prefer some types of people over others as well. The reason for your preferences, or the preferences of any other organism, has to do with that organism's history of reinforcement. If you have received lots of reinforcement from a particular person, or say, from people of a particular type, you would be more likely to seek out and interact with people like that as opposed to people you might have no experience with, or perhaps a person or type of people you might have had a bad experience with. You might be particularly drawn to a certain type of dog because it is similar to a dog you had in the past that was a really great dog. For all we know about your dog, he was fed and walked by a man before he got to you, thus he has a better history with men.

However, I suspect that this might not be exactly what is happening here. I wonder if your dog has learned something that many children learn. This is basically, mom is a pushover, and you can get away with stuff with mom. Dad on the other hand, when he says something, he means it. We don't  know the exact history of your dog, and this learning may not have even occurred with you specifically. For all we know, he lived in a house with a male and female, where this was the situation. Dogs generalize in really funny ways. He could have learned that when a man tells him to do something, he'd better do it, because it will be enforced. I'm not even saying he has been abused or anything, but simply that, if the man told him to sit before he could have his food, the man may have stuck to  not letting him have his food until he did it. If the woman of the house said to sit , and the dog didn't, she may have just put the food down and let the dog have it anyway.

We really can't  tell exactly why your dog behaves exactly as he does, nor do we  really need to know it solve the problem. Keep going with the NILIF, both of you. Make sure you are applying the same rules so that he doesn't learn that if he doesn't get what he wants from one person, he can go to, or wait for the other. 

Oh, and in my house, when puppies have accidents, we roll up a newspaper, and hit the person who was responsible for the dog at that time. Not hard, just a light swat. You can even hit yourself. While you are administering this, it helps to make an appropriate statement about why the dog had an accident ("I wasn't watching the dog," "I waited too long to take the dog out";) to remind yourself of what to do in the future to prevent another accident.

"Oh, and in my house, when puppies have accidents, we roll up a newspaper, and hit the person who was responsible for the dog at that time. Not hard, just a light swat. You can even hit yourself. While you are administering this, it helps to make an appropriate statement about why the dog had an accident ("I wasn't watching the dog," "I waited too long to take the dog out";) to remind yourself of what to do in the future to prevent another accident."

where is the "like" button!!!

brilliant, will have to remember this advice and pass it on to others.

 A little quote we have in my field,I don't know where it's from, "the learner is always right." Substitute dog in there. I don't know who said that. Anyway, if the dog makes a mistake, he's not trying to spite you, and he doesn't know better. It often looks like he does,  or he should. If he knew better though, he wouldn't have made the mistake. Mistakes indicate that the dog didn't know better, and he needs more training.