Feed Analysis Flashcards
What is proximate analysis?
looks at the composition of feed, does not provide information about nutrient availability to the animal
What is dry matter?
It is the measure of how much moisture was in a feed. It is calculated by heating samples above the boiling point of water. Typically heat in an oven at 105C.
How do you calculate dry matter?
Final weight / initial weight
How do you calculate moisture?
100 - DM%
What is crude protein?
It is an estimate of protein and non-protein nitrogen compounds in the feedstuff. Two methods are used to measure nitrogen content in a sample: Kjedahl and Combustion method
Describe Kjedahl Method?
Classic way. Oxidize organic matter to CO2 which releases nitrogen as ammonia sulfate. Convert this into ammonia, titrate, and calculate %N.
Describe Combustion Method?
Newer method. Burn sample and convert nutrient to gas. Isolate Nitrogen gas and convert into N2. Calculate
How can you calculate %CP from N?
N% x 6.25
What other ingredients has a portion of nitrogen?
NDICP, ADICP, or ICP
What is crude fat?
the measurement of fat in a feed using ether extract. Ether solvent extracts lipids from a feed sample
How do you calculate crude fat?
(initial weight - fat-free sample) /
initial weight
What is crude fiber?
Estimates cellulose, hemicellulose, lignin, pectin, and ash. Procedure attempts to simulate the pH-related digestive processes in the stomach.
1. boil in weak acid
2. boil in weak base (alkali)
3. burn until ash remains
How do you calculate crude fiber?
(digested sample - ash residue) /
initial sample weight
What is NDF and ADF?
Not a part of proximate analysis but better estimate of fiber digestibility.
ADF = cellulose, lignin
NDF = cellulose, lignin, hemicellulose
What is ash?
estimate of inorganic minerals. requires you to heat sample at 600C for 6 hours
