For the precision of individual and descent control different calculat
ions were carried out by DNA-fingerprinting using the probe (GTG)5. Th
e investigations based on a model population whose offsprings included
32 per cent of the total population of German Friesians in the catchm
ent area of the ZEH (Zuchtrinder Erzeugergemeinschaft Hannover). The p
robability for the occurrence of an identical DNA-fingerprint within t
he population investigated varied between 9.76 x 10(-7) (JEFFREYS et a
l., 1985) and 4.31 x 10(-5) (LAPLACE, 1812) depending on the different
ways of calculations. The precision of a descent control by DNA-finge
rprint amounts on the average 97 per cent. However, these results vari
ed obviously dependent on the frequency of informative bands. Addition
ally, three male half-sibling groups (German Friesian) and ten differe
nt breeds were investigated in regard to similar DNA-fingerprints. Bas
ed on 564 data files the correlation between additive genetic relation
ship and band-sharing was calculated. Animals of one breed that are no
t related due to their pedigrees showed an unexpectedly high band-shar
ing probability of 42.5 per cent.