Aerobic Stability

Aerobic stability is the length of time silage resists heating and spoilage after the pile is opened and exposed to oxygen. It’s typically measured in hours from face exposure to a 2°C rise above ambient temperature.

Industry references:

• <24 hours — unstable. Shrink at the face will be heavy.
• 24–72 hours — average. Manage face exposure carefully.
• >72 hours — stable. Operations with stable silage can run heavier face exposure without losing dry matter.

Aerobic stability is largely set at ensiling. The drivers:

• Initial pH and acid profile. A stable fermentation produces lactic and acetic acid in proportions that suppress yeast and mold during feedout.
• Packing density. Tighter packing = less oxygen ingress at the face.
• Inoculant choice. Lactobacillus buchneri is the classic inoculant added specifically to improve aerobic stability through acetic acid production.

Aerobic stability matters operationally because it determines feedout-phase shrink. A pile with 24-hour stability and a slow feedout pace will lose meaningful dry matter at the face every day. The same pile with 72-hour stability tolerates the same feedout pace with much less loss.

Sample silage for aerobic stability when face spoilage is visibly worse than expected, or when comparing inoculant choices across years.