What is the difference between ISR and Oldenburg NA?
Oldenburg NA maintains two mare books: The Premium Mare book and the Main Mare book. ISR uses the same mare books and in addition maintains the Mare book and the Pre Mare book for mares of good sport horse type and good movements, but without sufficient pedigree information or registration documents. Foals of Mare book and Pre Mare book mares will be registered ISR. ISR horses are also eligible for the ISR/Oldenburg N.A. USDF awards.