Andreasen B, Larsen B
Acta Vet Scand. 1976;17(2):264-6. doi: 10.1186/BF03547936.
In recent years parentage control by means of blood grouping tests (blood and protein systems) has been required for bulls to be registered in the Danish Hereford Herd Book. Because the Hereford breed shows less variation in the blood and protein systems, the probability of excluding an incorrectly stated bull (or cow) is estimated to be some 15 % lower in Hereford than in Danish dairy breeds (RDM, SDM and Jersey).