Dry Matter Calculator

Dry Matter Calculator

Convert feed and crop measurements from as-fed basis to dry matter basis. Essential for accurate livestock nutrition and feed analysis.

Last updated: March 2026

Weight in pounds or kg (leave empty for percentage only)

Moisture content as percentage (0-100)

Protein, fiber, or other nutrient percentage as-fed

Enter moisture percentage to calculate dry matter

What is Dry Matter?

Dry matter (DM) is the portion of feed or crop remaining after all moisture has been removed. It represents the actual nutritional content of feed—the proteins, carbohydrates, fats, minerals, and fiber that animals can utilize for growth, maintenance, and production.

Feed moisture content varies significantly between different types of feed and even within the same feed type depending on storage conditions and harvest timing. Fresh silage might contain 60-70% moisture, while dry hay contains only 10-15%. Comparing feeds on an as-fed basis can be misleading because you're comparing different amounts of actual nutrients mixed with different amounts of water.

Converting to a dry matter basis standardizes comparisons by removing the variable of moisture content. This allows accurate assessment of feed value, proper ration formulation, and meaningful cost comparisons. Nutritionists and feed analysts always express nutrient requirements and feed composition on a dry matter basis for these reasons.

How to Calculate Dry Matter

The Formulas

Dry Matter % = 100 - Moisture %
DM Weight = As-Fed Weight × (DM % / 100)
Nutrient on DM = (Nutrient As-Fed / DM %) × 100

Measuring Moisture Content

Oven Method:Weigh sample, dry in oven at 60°C (140°F) for 48 hours, re-weigh. Calculate moisture loss.
Moisture Tester:Use a commercial moisture meter designed for feed and grain analysis for quick results.
Laboratory:Send samples to feed testing lab for accurate moisture and complete nutrient analysis.
Published Data:Use standard reference values for common feeds (e.g., dry hay ≈ 10-15% moisture).

Example Calculation

Compare protein content of corn silage and alfalfa hay:

Given:
Feed: Corn silage
As-fed weight: 100 lbs
Moisture: 65%
Protein as-fed: 3%
Step 1:
Calculate dry matter percentage:
DM % = 100 - 65 = 35%
Step 2:
Calculate dry matter weight:
DM weight = 100 lbs × (35 / 100) = 35 lbs
Step 3:
Calculate protein on dry matter basis:
Protein DM = (3 / 35) × 100 = 8.57%
Result:
8.57% protein (DM basis)

While corn silage appears to have only 3% protein as-fed, it actually contains 8.57% protein on a dry matter basis. This is the true protein concentration and allows fair comparison with dry feeds like hay (typically 15-20% protein DM).

Frequently Asked Questions

Why is dry matter important for livestock?

Animals don't eat moisture—they eat nutrients. Comparing feeds on an as-fed basis is misleading because high-moisture feeds appear less nutritious. DM basis reveals true nutrient concentration for accurate ration formulation.

What's typical moisture for common feeds?

Silage: 50-70%, Haylage: 40-60%, Dry hay: 10-18%, Grain: 10-15%, Pasture: 75-85%. Fresh forages are mostly water, while processed feeds and grains are much drier.

Should I always use DM basis?

For comparing nutritional value and formulating rations, yes. For practical feeding (how much to physically feed), use as-fed weights. Most ration software converts between them automatically.

How does moisture affect feed cost?

You're paying for nutrients, not water. A feed at $200/ton with 50% moisture costs $400/ton DM. Compare feeds on $/ton of DM to determine true value.

Can moisture be too low?

Yes. Overly dry hay (<5% moisture) is brittle, loses leaves, and has reduced palatability. Grain stored too dry (<10%) can actually deteriorate. Ideal moisture depends on feed type and storage method.

How often should I test moisture?

Test each new feed lot or harvest. Moisture varies by weather, maturity at harvest, curing time, and storage. Even the same field harvested different days will vary.

What if I don't know moisture content?

Use published average values as estimates, but for accurate rations, test your specific feed. Even 5-10% moisture difference significantly impacts nutrient delivery and can under or overfeed animals.

Does DM change during storage?

Yes. Fermentation in silage produces heat and gas, reducing DM. Hay left exposed to rain increases moisture. Properly stored dry feeds maintain fairly stable DM over time.

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