Among the many research presentations, one study from the United Kingdom stood out to me. Their work focused on a seemingly simple but crucial aspect of silage management — the type of plastic used to cover silos. While polyethylene is the most commonly used material due to its affordability, it has a significant drawback: it allows some oxygen to pass through. This oxygen permeability can compromise the ensiling process by allowing the growth of spoilage organisms like molds and yeasts. In contrast, oxygen barrier films are designed to minimize oxygen diffusion, offering the potential for better silage preservation.
To test this, the researchers created 12 mini-silos using mason jars filled with chopped sorghum. Some jars were sealed with polyethylene, and other jars with oxygen barrier film. After 52 days of fermentation, the results revealed notable differences in silage quality and preservation.
Silos sealed with polyethylene recovered only 86% of the original biomass, meaning that 14% was lost during fermentation. On the other hand, those sealed with oxygen barrier film recovered 90.8% percent of the initial biomass, reducing fermentation losses to less than 10% percent. This difference in recovery can be substantial, especially when feed inventories are tight and every ton of silage counts.
Another important observation was the extent of spoilage. In the polyethylene-covered silos, 24.6% of the recovered biomass was deemed inedible due to mold contamination. In contrast, the oxygen barrier silos showed much lower spoilage rates, ranging from 7.4% to 11.1% percent. These findings were supported by microbial analyses, which showed higher yeast and mold counts in the polyethylene silos. Interestingly, when it came to fermentation characteristics, such as pH and organic acid concentrations, the differences between the two treatments were minimal.
With the harvest season for corn and other summer annuals fast approaching, this study serves as a timely reminder of the importance of proper silo sealing. If your goal is to maximize silage inventory and reduce losses, investing in an oxygen barrier cover may be a worthwhile consideration. While it may come at a higher initial cost, the potential savings in preserved feed and reduced spoilage could make it a valuable addition to your forage management toolbox. Let’s remember that good silage starts with good decisions — and sometimes, the difference is just a better cover.
