What major is the best of you want to be a Pediatrician or Veterinarian?

You can major in anything you're most interested in, as long as you take the courses required to get into the program you decide to go into. Both require a lot of science courses to ensure you have the foundation needed for the program. Most people will major in a science (e.g. biology, chemistry, animal science, physiology, etc), but that shouldn't limit you!