Hi and welcome, I'm Dr Deb and will give you some advice
Both of these breeds are bred to chase small creatures so he is just acting normally. Unfortunately his normal and human normal are not always the same
we need to modify the behavior. Do you have a crate? It would be used to put the cat in.
Yes, we have both one of those enclosed kitty sized plastic crates and also a metal, open type dog crate
The idea would be to have the cat in the room, but in a safe place (the crate) and have the dog with you,say, near the couch and on a leash. The cat would be 10 ft away and not directly threatened.
So have her in her own crate, not the metal dog crate correct?
You would sit on the couch and the dog, I assume, would be reacting to the cat. You would completely ignore the dog until he turns to you and away from the cat or is quiet for even several seconds. Give treats and praise.
the cat could be in either as long as safe from the dog.
if the dog reaction is very exuberant, it sounds like it is, you could even start with the cat in the crate in another room
So keep the dog at a safe distance, restrained. Ignore barking, whining but reward when he turns his attention away from kitty and toward something else
His reaction is and I am sure part of what we are seeing is the territorialness since she has now entered his home.
yes, or is just quiet and stops pulling and barking. You may want to do this on a day you have some time.
Both are still in transition after only 1 week being under the same roof.
Territory is something that is really only an issue between members of the same species. I think the dog is just acting out about the cat as a "normal" reaction
So should we also keep the door to the basement closed, to protect kitty until the dog seems more uninterested?
Or let her try to come up if she wants (I doubt she will as she seems pretty scared right now)
This is something that will take some time to do. You are changing a behavior bred into the dog- in his DNA sort of. You may try it for an hour or 2, then if he starts to pay more attention to things other than the cat, stop and try it again the next day
I don't think the cat should always be in the basement, if the dog is crate trained- put him in the crate at night and let the cat roam.
they should be kept separate though, you are right
Ok we will try that. Thanks for the advice.