Abstract: The invention relates to growth-promoter fodders or feed additives, comprising as active ingredient 0.002 to 98% by weight of prenylamine or a salt thereof, suitable for feeding purposes, in admixture with 99.988 to 2% by weight of an inert fodder carrier and optionally with further feed additives.The growth promoting fodders and feed additives of the present invention provide high weight gain, good fodder utilization and do not cause resistance or cross-resistance.