Submitted to: Transactions of the ASABE
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/1/2009
Publication Date: 3/5/2009
Citation: Shinners, K.J., Huenink, B.M., Muck, R.E., Albrecht, K.A. 2009. Storage characteristics of large round and square alfalfa bales: low-moisture wrapped bales. Transactions of the ASABE. 52(2):401-407.
Interpretive Summary: Hay is a main component of cattle rations, but baled hay needs to be below 20% moisture going into storage in order to keep bales from spoiling. In the humid areas of the U.S., farmers often have a difficult time getting hay that dry without rain damage. We studied a possible alternative: wrapping bales in stretch-film plastic. The plastic film keeps out the oxygen needed by spoilage microbes to grow. When wrapped alfalfa bales were made at moisture ranges typically used for making hay crop silage (40 to 60%), the bales fermented normally and had low losses in storage (3.5%). We also made wrapped bales at 30 to 40% moisture (a moisture range that poses a fire risk for dry hay or silo storage). These bales had little fermentation, but remained cool and had very low losses (2.3%). These results suggest that bale wrapping is a good alternative when farmers are trying to make hay without rain damage but the crop is not dry enough for safe storage.
Technical Abstract: Substantial dry matter (DM) and quality losses have been reported for partially dried alfalfa that has been rained on before moisture reduction to levels acceptable for dry hay storage. The objective of this research was to determine the feasibility of preserving alfalfa baled at less than 45% moisture (w.b.) by wrapping in plastic film. Large round and large square bales were stored and preserved as individually or tube wrapped silage bales at two moisture ranges: approximately 40 to 55% and 30 to 40% w.b. The tube wrap system was 50% more productive while requiring 43% less plastic compared to individually wrapped bales. Storage characteristics were quantified by DM loss, change in nutrient composition, fermentation products, and heating after removal from storage. Average DM loss during storage was 3.5 and 2.3% for the high and low moisture ranges, respectively. There were generally no significant differences in DM losses or nutrient retention between round and square bales, bales wrapped individually or in a tube or high and low moisture ranges. Fermentation products were significantly affected only by initial moisture content. Heating rate of the low moisture silage bales after removal from storage was acceptable, taking seven or more days to heat to 35°C. Although below the moisture range usually considered acceptable for chopped silage in bunk or bag silos, preservation of bales at both moisture ranges was excellent despite the low production of desirable fermentation products.