ARS | Publication request: ADVANCES IN SILAGE PRESERVATION

Submitted to: Four-State Forage Conference
Publication Type: Experiment Station
Publication Acceptance Date: February 22, 2003
Publication Date: March 25, 2003
Citation: MUCK, R.E. 2003. ADVANCES IN SILAGE PRESERVATION. In: FOUR-STATE FORAGE CONFERENCE, March 25-26, 2003, Baraboo and Prairie du Sac, WI. p. 41-45.

Technical Abstract: More silage is being made in bunker and pressed bag silos. These silo types require more management skills than more traditional tower silos to obtain a high quality silage. This paper covers recent silage research of relevance to managing bunker and bag silos. These silo types allow ensiling of wetter crops. However, this increases the possibility of a clostridial or butyric acid fermentation. Butyric acid at above 0.5% dry matter (DM) reduces intakes and increases the risk of ketosis in dairy cattle. Clostridia are found in soil and manure, and their presence on forage at ensiling can be reduced by minimizing soil contamination and by only applying manure to hay fields shortly after harvesting. The other key to preventing clostridia is to ensile hay crop silages at less than 70% moisture. A high density in silos is important in reducing storage costs and minimizing spoilage losses. A survey of more than 170 bunkers found five factors correlated with high density: packing tractor weight, layer thickness, packing time per as fed ton, silage height, and DM content of the crop. We are currently verifying these factors in a pilot-scale compactor. Pressure applied (i.e., tractor weight) and packing time per layer appear more important than layer thickness in this pilot-scale compactor. Increased packing time increases density, but the magnitude of the increase goes down for each additional unit of time spent. In monitoring 47 bag silos made at three research stations in the Madison area, DM density has been affected by DM content, bagging machine, set up of the bagging machine, crop and kernel processing. Average losses from 24 bags have been 9.6% invisible losses and 6.9% spoilage loss. These averages were inflated by six bags with substantial spoilage. Removing the six bad bags reduced average total losses to 11.4%. Invisible losses increased with low feed out rates (<12 in./day) whereas spoilage losses were associated with drier (<60% moisture), more porous silages. Also spoilage losses were higher in bags fed out over the summer months or damaged by birds. Finally, we have been studying new inoculants aimed at improving the aerobic stability of corn silage. Two approaches are in the marketplace: an enhanced standard inoculant and Lactobacillus buchneri, heterofermentative lactic acid bacteria to increase acetic acid in silage. The L. buchneri inoculants were the most consistent at increasing aerobic stability, but research has yet to show increases in animal performance with these inoculants.