Dr. Sonja Egan:

The green book is what we term a stud book passport. That is where the animal is entered into a specific stud book - typically with its breeding recorded. There is some method of entry for animals with a white book or identification document and that is typically through judgment, so that is an inspection or selection process. Typically, what happens with a white book animal is that it does not have its parentage or breeding recorded hence it is not eligible to enter into a stud book. That is specifically governed with the stud book rules, which would be approved by the Department within a cross-breeding programme. Animals of a specific breed would be eligible to enter through a cross-breeding programme. Not all equine breeds are listed within the green book specific breeding programmes hence some animals may have breeding recorded but due to their specific parentage or breed listed, are not eligible to enter a green book stud book.