Air at the face spoils the pack
Dense packing and oxygen-barrier cover lock fermentation in. A ragged, slow face lets air back in and burns dry matter at the bunk.
3 min read · 2026-09-09
In this note
- ~30–35%
- ~30–40%
- ~4–7%
- 15–16 lb
Silage quality is decided long before the TMR mixer. Once forage is chopped, the pack is a race against oxygen: dense packing and a real oxygen-barrier cover lock fermentation in; a ragged, slow-moving face lets air back in and burns dry matter, energy, and bunk life.
Success needs alignment among the forage grower, harvesting contractor, and livestock manager — with the nutritionist moderating toward shared dry-matter, particle-size, and fermentation targets. Misaligned harvest windows or packing rates show up later as heating at the face and selective sorting at the bunk.
Aim for a minimum bulk density near ≥700 kg as-fed (AF)/m³ (about 44 lb AF/ft³) so porosity stays low across normal ensiling dry matters; companion DM-density targets are often ≥15–16 lb DM/ft³. Say AF vs DM out loud — they are not the same number. Whole-plant corn silage is commonly harvested around ~30–35% DM, with fermented silage often landing in a broader ~30–40% DM window; well-preserved corn silage typically shows pH ~3.7–4.2 and lactic acid ~4–7% of DM (Kung & Shaver).
A smooth, progressive face and a removal rate that keeps pace with the herd limit reheating. Spoiled surface layers that reach the bunk depress intake and dilute the fiber and energy the rumen was formulated for — so face discipline is energy and delivery, not just "storage hygiene."
Walk the face: heating, mold seams, and a soft shoulder mean oxygen is winning. Tighten cover edges, raise packing density next fill, and match face advance to daily disappearance before blaming the ration.
Keep reading
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Particle size holds the fiber mat
If the TMR is too fine, the forage raft thins — less trapping, less re-chewing, less bicarbonate-rich saliva.
Sister note · 3 min
Home plate: Rumen · Inside the rumen
- Inside the rumenA dairy cow is a microbial fermentation system. Open the vat: four compartments, a stratified rumen, chewing, acids, and what leaves downstream.Placed here
- Read manure before you rewrite the ticketThe alley is a daily report card on the ration the cow actually ate and fermented — consistency, fiber, and grain tell you before the mixer does.Same sheet
- The sensor is a barn alarm, not a diagnosisRumination and activity collars flag deviations from a cow’s own baseline — useful alarms that still need the cow, bunk, and stall before you act.Same sheet
- Intake & the energy gapIntakeBridge → Transition
Mark size is the kind. Color is the atlas area.
- Sheet
- Focus
- Field note
- Rumen
- Transition
Sources
- Packing Bunkers and Piles to Maximize Forage Preservation — UW–Madison Extension (Holmes & Muck)
- Interpretation and Use of Silage Fermentation Analysis Reports — UW–Madison Extension (Kung & Shaver)
- Silage Management Considerations — LPELC / University extension consortium
- Silage Harvesting, Storing, and Feeding — UF/IFAS Extension (SS-AGR-177)
- Chopping and Storing Quality Corn Silage — Utah State University Extension