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):
Danmark (link to Danish page)
EU (or Switzerland, Iceland, Liectenstein and Norway)
Other countries (not Denmark, EU or Switzerland, Iceland, Liectenstein and Norway)