Fieldstudys on 22 farms (23 silos) to study relationships between the actual particle size of the maize silage and the theoretical length of cut. The measure of theoretical length of cut were stated by the farmers and not measured by us. Particle size of maize silage was determined using the New Penn State Forage Particle Separator. SLU Skara made a special sieve for us, that had larger holes than de original sieves. The samples were shaken after instructions and then the material was weighted. We have also been taking out samples for microbiological analyses from the silos on 13 of the farms.