Fundamental Concepts: Proximate Analysis

Question 1

What is nutrient analysis?

Answer 1

A test done on a feed sample to determine nutrient content using either chemical, biological, or enzymatic methods

Question 2

What is the wet chemistry method?

Answer 2

Analyses feed sample in liquid form
Original method of feed analysis
More accurate

Question 3

What is the NIRS method?

Answer 3

Uses light reflect acne to measure a feed sample
Faster and cheaper
More precise

Question 4

What is proximate analysis?

Answer 4

Determines the composition of a feed sample in terms of nutrients

Question 5

Who developed the proximate analysis method?

Answer 5

Developed in the 19th century at the Weende experiment station by Henneberg and Stahmann

Question 6

What are the steps to proximate analysis?

Answer 6

1. Take multiple small samples from different locations
2. Mix all samples into a large composite sample
3. Sum of composite sample is collected
4. Do not shake to maintain sample integrity

Question 7

What does proximate analysis measure?

Answer 7

Dry matter, crude protein, ether extract, ash, crude fiber, and nitrogen free extract

Question 8

How is dry matter (DM) calculated?

Answer 8

1. Feed is dried at 105 degrees Celsius overnight
2. Calculate: (dried feed sample/original feed sample) x 100

Question 9

What is the Kjeldahl method?

Answer 9

Developed by Johan Kjeldahl to determine crude protein (CP) from nitrogen content in a feed sample.
Calculation: N x 6.25

Question 10

How is ether extract (EE) calculated?

Answer 10

1. Boil dried fat content sample in diethyl ether for 4 hours
2. Most sample will separate or evaporate
3. Leftover residue is weighed

Question 11

How is ash or total inorganic component calculated?

Answer 11

1. Heat sample at 500-700 degrees Celsius for 2-4 hours
2. Leftover residue is weighed

Question 12

How is crude fiber (CF) calculated?

Answer 12

1. A dried feed sample is boiled with a solution of 1.25% hydrogen sulfide and then filtered
2. Leftover residue is dried and ashes
3. Calculation: filtered dried sample weight - ash weight

Question 13

How is nitrogen free extract (NFE) calculated?

Answer 13

Calculated value is not analyzed only a guess
%NFE = (%DM - (%EE + %CP + %ash + %CF))

Question 14

What is the van soest analysis method?

Answer 14

An improved method of feed analysis where neutral detergent fiber (NDF) and acid detergent fiber (ADF) is calculated

Question 15

What composes NDF?

Answer 15

Hemicellulose, cellulose, and lignin

Question 16

What composes ADF?

Answer 16

ADF protein, lignin, and cellulose