When you are breeding dogs, the puppy will have a red collar no matter what colour of the parent's collar is. For example, if you breed two blue collar dogs the puppy's collar will become red while if you breed two blue collar cats the kitty's collar will become blue. 

Also, I was unable to drop a file to show you an example so I just uploaded a video to youtube: https://youtu.be/eOtPQYHkLxc