ANS230: Lecture 31 : Feed Analysis & Nutrient Composition - As Fed vs Dry Matter

What two factors drive the need for very accurate feed analysis?

Feed costs and production

In feed analysis, do you want precise or accurate results?

Accurate

What happens to nutrients that are not efficiently utilized and thus wasted by animals?

They are excreted into streams and into the environment

What are the two basic components of a feed?

• Water

• Dry Matter

What two classifications can dry matter be divided into?

• Organic

• Inorganic

What is the only inorganic nutrient?

Minerals

How many pounds make a kilogram? (could be helpful for conversions)

2.2 lbs

What two macrominerals are reported as percentages in feed analysis’s?

• Calcium

• Phosphorous

When you take a sample, do you want it to represent the larger or smaller bulk of the feed?

Larger

What is the first thing you do in a lab for a feed analysis?

Dry out the feed sample; remove the water

What test do you undergo to figure out how much fat is in your feed sample?

Ether Extraction

What does ether extraction yield?

Crude Fat

Once the the ether extract oil is removed, what is left from the EE procedure

Residue

What procedure occurs once you have your residue?

Fiber Analysis

What are the two types of Fiber Analysis’s?

• NDF (Neutral Detergent Fiber)

• ADF (Acid Detergent Fiber)

Is the pH of detergent used in NDF high or low?

High

Is the pH of the detergent used in ADF high or low?

Low

What three components make up NDF?

Cellulose, hemicellulose, and lignin

What two components make up ADF?

Cellulose, lignin

Which valeu do we expect to be higher, NDF or ADF?

NDF, bc it has more components of the cell wall

Who invented the procedure for fiber analysis?

Dr. Peter Van Soest (Cornell)

Why does it make sense that Hemicellulose is broken down by acid detergent and the other two components of the cell wall dont?

This is because hemicellulose is the most digestible out of all the components, and thus I reason that parts of it aren’t as strong

How do you calculate Nitrogen Free Extract?

%NFE = 100% - (%EE + %CP+ %Ash +%Fiber)

What does the NFE consist of?

The soluble materials in the field (ex. sugars, starches, and glycogen)

NFE is a rapidly ______ fraction.

digetible

What is the procedure called to figure out Nitrogen/CP is in the feed?

Keldahl Procedure

Do you measure nitrogen or crude protein in feeds?

Nitrogen

How do we calculate crude protein from a nitrogen value?

N * 6.25

How do you determine the mineral or ash portion of the feed?

You boil the fiber components in a 400 degree celsius solution.

What are the two names for the food analysis procedured talked about above?

• Proximate Analysis

• Van Soest Detergent System

What does TDN (Total Digestible Nutrients) do?

It gives you an estimate of how much of those nutrients in the feed are digestible

What is more accurate for assessing the digestibility of nutrients: Net Energy or TDN?

Net Energy

What is “As Fed”

It is the way animals consume the feed

How does dry matter related to “as fed”?

Its the same meal as “as fed,” just without the water component

What happens to the dry matter percentages once water is taken away?

They increase

“The concentration of a nutrient is _______ when expressed on a 100% dry matter basis.”

greater