The pips do contain a small amount of arsenic so are probably best avoided although to be honest they would have to eat one heck of a lot of them to cause any harm.
My 2 small dogs love apple and I always bite them out a bit each when i have one. They also help themselves to any windfalls from my tree if they can get to them before I do.
One of my Danes eats apples from the tree like they're going out of fashion! But then the only thing I have found that she won't eat is raw broccoli....strange girl she is!
I know lots of dogs that go for the apples in the orchard where we walk.Doesn't seem to harm them except for a bit of wind apparently so not good for your house!