Dry Matter vs AsFed Basis Dry Matter vs

Dry Matter vs. As-Fed Basis

Dry Matter vs. As-Fed • Important concept in feed analysis • Expression of nutrient content or feed amount on a "dry matter" or "as-fed" basis

Dry Matter vs. As-Fed • All feeds contain water, some more than others • Consider: Alfalfa pasture = 80. 2% water Alfalfa hay = 9. 5% water

Dry Matter vs. As-Fed • When comparing the nutritional value of feeds, • It must be done on a dry matter basis to be valid

Dry Matter vs. As-Fed • As-Fed – as normally fed to animals • Contains water • Dry matter – does not contain water

Dry Matter vs. As-Fed • DM content of a feed is the most important component because it contains almost all of the nutrients • DM in a feed is: % dry matter = 100 – % water

Dry Matter vs. As-Fed • Alfalfa pasture = 80. 2% water DM = 100 – 80. 2% = 19. 8% • Alfalfa hay = 9. 5% water DM = 100 – 9. 5% = 90. 5%

Dry Matter vs. As-Fed • Compare protein content of the alfalfa pasture and alfalfa hay • On an as-fed basis, alfalfa hay appears to contain more protein 19. 0% vs. 4. 1%

Dry Matter vs. As-Fed • On a dry matter basis, however, the hay and pasture are very similar 21. 0% vs. 20. 7% • The as-fed protein comparison is misleading

Concentration (%, Mcal/kg) Start with As-Fed Basis of Nutrients (The “pie” represents nutrients in a feed)

Concentration (%, Mcal/kg) Convert to DM by removing water

Concentration (%, Mcal/kg) Notice how nutrient %’s go up (The “pie” represents nutrients in a feed)

For A Nutrient Concentration • As-Fed to DM Nutrient % gets BIGGER (Because water is removed) • DM to as-fed Nutrient % gets smaller (Because water is added back in)

Feed Amount (g, lb, etc. ) As-Fed Basis Weight = 5 lb (Contains water)

Feed Amount (g, lb, etc. ) Dry Matter Basis Weight = < 5 lb (Water removed)

For A Feed Amount • As-Fed to DM Feed amount gets smaller (Because water is removed) • DM to as-fed Feed amount gets BIGGER (Because water is added back in )