Submitted to: Transactions of the ASAE
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/25/2006
Publication Date: 11/1/2006
Citation: Muck, R.E., Holmes, B. 2006. Bag silo densities and losses. Transactions of the ASABE. 49:1277-1284. Interpretive Summary: Bag silos are being used increasingly on dairy farms because of their low purchase cost and the management flexibility they provide relative to other silo types. Unfortunately almost no research has been done on densities and losses in bag silos. These factors are important in determining the true cost of producing a ton of silage. We measured densities on 47 bag silos (24 hay crop silage, 23 corn silage) made at 3 research farms. Dry matter density ranged from 10 to 17 lbs./cubic feet and was affected by how the operator set up the bagging machine. Dry matter density also increased when drier crops were ensiled and when crops were chopped finely. Losses were measured on 39 of these silos and ranged from 0 to 40%. Average losses were 14.6%. Excessive spoilage occurred in 6 bags and was due either to holes in the silos that were not patched promptly or to dry silages (<60% moisture) emptied in warm weather. The results indicate that losses below 10% are possible with good management. These results will help farmers more accurately compare bag silos with other silo types and provide them with guidelines that will help them obtain high quality silage from bag silos.
Technical Abstract: Bag silos made at three research farms in 2000 and 2001 were monitored at filling and emptying to determine densities and losses. A total of 47 bags (23 alfalfa, 1 red clover, 23 whole-plant corn) were made, and losses were calculated on 39 of the silos. Dry matter (DM) density ranged from 160 to 270 kg/m^3. Dry matter density increased with DM content in hay crop silages on average 3.0 kg/m^3-% DM whereas the effect in corn silage varied by bagging machine. Density decreased with increasing particle size at 4.1 kg DM/m^3 per mm. The operator and how the bagging machine was set up affected density. A wide range of DM losses was observed, 0 to 40%. Average DM losses were 9.2% invisible plus uncollected losses and 5.4% spoilage losses for a total loss of 14.6%. Six silos had excessive spoilage losses of more than 15% and total losses above 25% due to plastic integrity issues or overly dry silage (>40% DM) being fed out in warm weather. Invisible losses were reduced in high porosity silages (where spoilage losses were exacerbated), greater in warm weather, and affected by emptying procedures. Spoilage losses in bags without plastic integrity issues were greater in dry, porous silages, from emptying silos in warm weather, and at lower feed out rates.