Stretch-wrap plastic is usually one mil (0.001 in) thick and comes in rolls of 5,000 or 6,000 ft. The plastic is typically pre-stretched 50 to 70% on the wrapper’s film dispensing unit to get the correct tension on the bale surface. Always ensure that the tension of the wrap (tacky side toward bale) is such that film is stretched uniformly on the bales. Apply at least four layers should be applied to each bale. For an individual bale wrapper, the preferred method is the 2+2 system whereby two layers of wrap are applied during one rotation of the bale by a 50% overlapping of
successive layers. Keep in mind that some types of wrappers dispense plastic differently than others. In-line wrappers can be purchased to dispense 4 rolls at a time rather than the standard 2 roll types. The 4-roll system increases wrapping speed. Some in-line wrappers also allow extra plastic to be applied at the joints between bales. If this option is available, apply 2-4 extra layers at these joints. Use the high end of this range if bales lack uniformity or do not match up well at the joints. Do not apply too little plastic or oxygen will penetrate the bale and cause spoilage, mold growth, and feed losses.

The plastic used in baleage does not create an airtight seal. Low-density polyethylene plastic such as that used in silage films is four times more permeable to carbon dioxide gas than it is to oxygen gas, allowing the bales to vent excess carbon dioxide gas as fermentation begins.