For those with bunker silos, there’s a new study that suggests using an oxygen barrier (OB) up the sides and partway across the top will reduce spoilage and waste. Researchers in Brazil captured multiple corn silage samples from eight different silos that were differently covered one side to the other. Half of the filled bunker had a sheet of 45-μm-thick OB film (PE + EVOH) lining the side and folding over the top by approximately 6.5 feet (see figure B). Over the top of the entire bunker was a standard (ST) 180-μm-thick polyethylene (PE) film. Central core silage samples were compared to samples from just below the surface from both the OB and ST sides (see figures A & B).
The quality profiles of the OB samples were very similar to the core samples in terms of pH, TDN (total digestible nutrients), mold concentration, and most other variables. In contrast, the ST samples had significantly higher pH, higher mold and yeast concentrations, and lower starch and TDN compared to the core samples. Silage samples closest to the walls showed the largest effect of the sealing system. Lining the bunker with OB film reduced aerobic spoilage on the shoulders, yielding higher quality feed that resulted in an estimate of 256 pounds more milk per ton of dry matter consumed. The authors recommend overlapping the OB film at least 200 cm (79 inches) on the top of the silage and weighting the top PE film (or tarp) particularly well at the walls.
SAFETY REMINDER: Silage faces are hazardous. Even a not-too-high, correctly shaved face can still collapse. No one who is not actively unloading from the feedout face should be anywhere in the area. A good rule of thumb is to stay at a distance of three times the height of the face. And don’t fill the bunker higher than the unloader can reach.
Lima et al. Lining bunker walls with oxygen barrier film reduces nutrient losses in corn silages. Journal of Dairy Science. 100:4565-4573, June 2017.
Other extension resources about silage bunker management:
Managing Forage in Bunker Silos from University of Wisconsin Extension