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Crude fibre

Macronutrients stored as g/kg 6 shared products have a value

What it is

Crude fibre is an older analysis that was intended to measure cellulose. It correlates closely with cellulose content but is imperfect by modern standards, and with nitrogen-free extract it is inadequate for estimating a feed's nutritive value [1].

Modern forage reports use the detergent fibre fractions instead: NDF, which measures hemicellulose, cellulose and lignin, and ADF, which measures cellulose and lignin [2].

Why fibre matters

Forage should make up most of a horse's diet; the MSD Veterinary Manual sets minimum forage intake as a share of body weight on a dry matter basis [3]. Replacing too much forage with high-starch concentrate disrupts hindgut microbes and raises the risk of colic [4].

Reading it on a label

Crude fibre, NDF and ADF measure different things, so a crude fibre figure on a feed bag can't be compared directly with an NDF or ADF figure on a hay test [1, 2].

See also ndf, adf, dry matter.

Sources

  1. 1. Van Soest PJ. Effect of environment and quality of fibre on the nutritive value of crop residues. In: Plant breeding and the nutritive value of crop residues. Food and Agriculture Organization of the United Nations (FAO). Undated (references to 1987). https://www.fao.org/4/x5495e/x5495e06.htm (accessed 2026-11-07)
  2. 2. Arispe S, Filley S. Understanding your forage test results (EM 8801). Oregon State University Extension Service. Revised October 2020, reviewed 2023. https://extension.oregonstate.edu/catalog/em-8801-understanding-your-forage-test-results (accessed 2026-11-07)
  3. 3. Liburt NR (peer reviewed by Boyle AG). Nutritional Requirements of Horses and Other Equids. MSD Veterinary Manual, Professional Version. Merck & Co., Inc., Rahway, NJ. Last full review February 2026. https://www.msdvetmanual.com/management-and-nutrition/nutrition-horses/nutritional-requirements-of-horses (accessed 2026-11-07)
  4. 4. Extension Horses (Cooperative Extension, USDA NIFA). High Fat Diets for Horses. horses.extension.org, 20 January 2020. https://horses.extension.org/high-fat-diets-for-horses/ (accessed 2026-11-07)

Last edited 7 Nov 2026, 1:48 am