The results of yield development and departure within two milk product
ion enterprises over a time of 10 years show that throughout a high yi
eld productive availability and a good length of productive life may b
e compatible. A high but not highest first lactation yield is an essen
tial assumtion. In simulate experiments the shifting of selection poin
t of time between each lactations at selection of the 75% best animals
(accordingly the practical selection of productive) doesn't lead to a
change of the cumulative yield of the animals. At selection of the 5%
best animals (accordingly the selection of bullmothers and donors) th
e shifting of selection point of time from the first to the third lact
ation leads to a higher cumulative yield of 16% in 5 lactations.