Upload
neil-sparks
View
218
Download
1
Embed Size (px)
DESCRIPTION
All feeds contain water, some more than others Consider: Alfalfa pasture = 80.2% water Alfalfa hay = 9.5% water Dry Matter vs. As-Fed
Citation preview
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
•All feeds contain water, some more than others
• Consider:Alfalfa pasture = 80.2% waterAlfalfa 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% waterDM = 100 – 80.2% = 19.8%
• Alfalfa hay = 9.5% waterDM = 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
Dry Matter vs. As-Fed
Concentration (%, Mcal/kg)
10
70
1 4 15
% As-Fed Basis
ProteinEnergyCalciumMineralsWater
Start with As-Fed Basis of Nutrients
(The “pie” represents nutrients in a feed)
Concentration (%, Mcal/kg)
10
70
1 415
% As-Fed Basis
ProteinEnergyCalciumMineralsWater
Convert to DM by removing water
Concentration (%, Mcal/kg)
12
82
1.24.8 % Dry Matter Basis
ProteinEnergyCalciumMinerals
Notice how nutrient %’s go up
(The “pie” represents nutrients in a feed)
• As-Fed to DMNutrient % gets BIGGER(Because water is removed)
• DM to as-fedNutrient % gets smaller(Because water is added back in)
For A Nutrient Concentration
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)
• As-Fed to DMFeed amount gets smaller(Because water is removed)
• DM to as-fedFeed amount gets BIGGER(Because water is added back in)
For A Feed Amount