The Danish Veterinary and Food Administration can issue authorisation to work as a veterinarian in Denmark. You must meet various requirements before you can obtain an approval.The requirements depends upon whether you have a degree from Denmark, EU or another country (not Denmark or EU):
Degree from Danmark (link to Danish page)
Degree from EU (or Switzerland, Iceland, Liechtenstein and Norway)
Degree from other countries (not Denmark, EU or Switzerland, Iceland, Liechtenstein and Norway)