Starch amount is not starch use
The starch percentage cannot show whether kernels were processed, fermented, digested, or lost in manure.
4 min read · 2026-09-17
Grain source, particle size, kernel processing, moisture, ensiling time, passage, and meal pattern change starch availability. A high starch result can coexist with poor utilization. A moderate result can ferment rapidly. Concentration describes the load. Processing and digestion describe what happens to it.
Fredin, Ferraretto, and Shaver showed fecal starch tracks total-tract starch digestibility closely enough to use as a barn check — it is an index of use, not a diagnosis. Pair the starch line with processing measures, an appropriate digestibility test, fecal starch when indicated, manure, and the SARA risk stack. The field lesson is to read dose and rate together.
Check in the barn
What to check: Kernel processing score or grain particle size, silage age, manure grain, and whether fecal starch was run on the pen that is disappointing you. If cows slug meals after an empty bunk, the starch arrival story may be behavioral, not a laboratory miss.
Sister notes on this universe cover nfc-is-not-starch. The starch-and-sara universe’s empty-bunks-are-starch-events and sara-is-not-grain-overload notes, and the inside-the-rumen universe’s read-manure-before-you-rewrite-the-ticket note, are how unused starch shows up in the cow. Educational only — not a diagnosis, prescription, or ration formula.
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NFC is not starch
Starch is one measured carbohydrate fraction; NFC is a calculated basket containing several non-NDF components.
Sister note · 4 min
Home plate: Rumen · Reading carbohydrates & energy · Starch
- StarchStorage carbohydratePlaced here
- Empty bunks are starch eventsCows that wait, then eat fast, drop pH even when the printed diet never changed.Sister note
- Energy 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.Sister note
Mark size is the kind. Color is the atlas area.
- Focus
- Field note
- Rumen
Sources
- Nutrient Requirements of Dairy Cattle, 8th revised edition — NASEM (2021)
- Fecal starch as an indicator of total-tract starch digestibility by lactating dairy cows — Fredin et al. (2014)
- Fecal starch calculator – Background and guide — UW–Madison Extension (Ferraretto & Shaver)