What it is
Dry matter (DM) is the feed without its water: DM% = 100% − moisture% [1]. "As fed" means the feed as offered to the animal, including its water [1].
Why it matters
Lab reports give each value twice: as fed, and dry (with all moisture removed). Dry values are better for comparing forages, matching tables (which are usually on a DM basis) and building rations [2].
To compare feeds, convert as-fed values to a DM basis by dividing by the DM fraction; for example, 9% crude protein in hay at 90% DM is 10% on a DM basis [1].
To find how much feed supplies a given amount of dry matter, divide by the DM fraction: 25 lb of DM from hay at 89% DM is 25 ÷ 0.89 = 28.1 lb as fed [1].
Forage intake guidelines for horses are expressed on a DM basis [3].
See also reading feed labels, 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)
- 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)
Last edited 7 Nov 2026, 1:48 am