Daughter doesn't like our new dog. Why?

My daughter and hubby have been bugging me about getting a dog for a while now. My daughter is 4 and an only child so I thought a dog would be a good playmate for her. We got a well behaved dog that a family member had to give up. But my daughter seems uninterested (not scared) and says that she only wants our cat now (the cat is not getting along with the dog and has to be separate). They are definitely not bonding. Any advice?