What it is
NDF measures the whole plant cell wall: hemicellulose, cellulose and lignin [1, 2]. Lignin is indigestible, while cellulose and hemicellulose can be partly broken down by microbes [1].
What it tells you
NDF is negatively correlated with intake [1]. It is associated with "fillability": high-NDF forages limit how much a horse eats, and because horses eat smaller meals than ruminants, A&L suggests a forage with a reasonable NDF of 45–50% lets them eat more [2].
As plants mature, the cell wall thickens and becomes less digestible [2].
See also adf, crude fibre.
Sources
- 1. 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)
- 2. A&L Canada Laboratories. Defining Analytical Constituents in Equine Feed Reports. Fact Sheet No. 234. London, Ontario. Revised February 2022. https://alcanada.com/Tech_Bulletins/Field_Crops/Forages/234-Defining%20Analytical%20Constituents%20in%20Equine%20Feed%20Report.pdf (accessed 2026-11-07)
Last edited 7 Nov 2026, 1:48 am