Glossary · Feed
Dry Matter (DM)
The portion of feed that remains after all water is removed. The unit dairies use to compare and ration feeds, because moisture content varies widely.
Dry matter (DM) is the portion of a feed sample that remains after all water has been removed. It’s expressed as a percentage — corn silage at “35% DM” means 35% of the as-fed weight is feed and 65% is water.
DM is the unit that matters for dairy nutrition for one reason: feeds vary enormously in moisture content. A wet corn silage and a dry hay are not comparable on an as-fed basis. Convert both to DM and they’re directly comparable.
Every silage measurement that matters operationally — tonnage on hand, dry matter intake (DMI) per cow, feed efficiency, shrink — is computed on a DM basis. Reporting feed numbers without specifying DM vs as-fed is the most common source of confusion in feed records.
Typical DM percentages:
- Corn silage: 32–38%
- Haylage: 35–55%
- High-moisture corn: 24–30%
- Dry hay: 85–90%