Majsensilage : partikelstorleksfördelning och hygienisk kvalité

Abstract: 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. One sample was taken 30 cm from the silos wall, (both walls), and one sample was taken from the middle of the silo. We did some shakings with the particle separator from the feed bunk to see if the particle size distribution was different in the beginning, in the middle and at the end of the feed bunk. The farms were situated in southern Sweden; Skåne, Småland, Kalmar- Öland, Östergötland, Mälardalen, Halland and Västergötland. In our studies we could not find any connection between farmers TLC and forage particle size. The cause of this might be velocity of the cutter and the aggressiveness of the kernel processer. In comparison with American recommendations, (Heinrichs and Kononoff, 2002), the studied maize silages had larger fraction of coarse particles. We could not find any big differences in TMRs particle size distribution in feed from the beginning, middle and at the end of feed tables. However we do not think that this part of our study is reliable anyway because of cows sorting in TMR, the TMRs different contents and the fact that we were not able to visit all farms just in time for their daily feeding. We have been able to see that cows sorted out big particles of fodder. The microbiological analyses showed that yeast occurred in 11 of 13 tested farms. There were also some mould growth of mainly Penicillium Roqueforti in the silages. The consistency of manure was looser in the dairy farms and firmer in the cattle farms and it was not possible to connect it with the maize silage, although the farmers seemed to think that the manure became firmer when maize silage was fed. Conclusions that we came to is that the actual particle size did not have any relationship with the theoretical length of cut and that Swedish maize silage have a larger fraction of coarse particles than American maize silages. We recommend to use corn cracker to give the maize silage better digestibility and when using aggressive kernel process you can increase TLC. It also is important that the silo size is adjusted to the daily feed rate otherwise yeast and mould easily grow in the cut surface.