Reading protein

Numbers

• Conventional CP calculation

  Nitrogen × 6.25

  The factor converts measured nitrogen to a crude-protein equivalent; it does not measure true protein directly.

  Oregon State University Extension

Compare

• Headline vs supply

  Crude protein

  • Nitrogen-based feed value
  • Includes several nitrogen forms

  Metabolizable protein

  • Whole-diet model output
  • Absorbable microbial protein plus digestible RUP

  CP and MP answer different questions.

Field notes on this focus

1. Note 01Crude protein is only the headlineCP counts nitrogen equivalents; it does not reveal solubility, rumen degradation, heat damage, or absorbable amino-acid supply.4 min · 2026-09-17

Also touches this focus

1. Note 01Escape protein still has to digestRUP describes rumen escape, not guaranteed intestinal absorption.4 min · 2026-09-17
2. Note 02A number without a unit is not a resultPercent, ppm, mg/kg, Mcal/lb, and Mcal/kg can turn the same digits into very different decisions.4 min · 2026-09-17
3. Note 03Energy on the report is a model outputRoutine NEL and TDN values are usually calculated from chemistry and assumptions, not collected as direct substances from the sample.4 min · 2026-09-17
4. Note 04Heat damage can hide behind CPNitrogen can remain in the sample even after heating makes part of it poorly available to the cow.4 min · 2026-09-17