lecture 6 - detergent analysis system

What does the detergent analysis system measure?

Feed carbohydrate fractions based on chemical composition

What does NDS stand for?

Neutral detergent solubles

What is found in NDS?

Sugars, fructans, starch, and pectin

What does NDF stand for?

Neutral detergent fiber.

What is found in NDF?

Hemicellulose, cellulose, and lignin

What does ADF stand for?

Acid detergent fiber

What is found in ADF?

Cellulose and lignin

What does ADL stand for?

Acid detergent lignin

How do you calculate hemicellulose?

NDF − ADF

How do you calculate cellulose?

ADF − ADL

Which fractions contain cellulose?

NDF and ADF

Which fractions contain lignin?

NDF, ADF, and ADL

Which carbohydrate is not fermentable by rumen microbes?

Lignin

How does lignin affect fiber digestion?

It limits microbial access to cellulose and hemicellulose

Which is fermented faster: pectin or cellulose?

Pectin

How quickly is hemicellulose fermented?

At a moderate rate.

How quickly is cellulose fermented?

Slowly

Which carbohydrates can animals digest directly?

Sugars and starch

What is high-quality forage generally characterized by?

High NDS, moderate NDF, low ADF, and low ADL

What is low-quality forage generally characterized by?

Low NDS and high NDF, ADF, and ADL

What is dietary NDF associated with?

Feed intake

Why can high NDF reduce intake?

It increases rumen fill and slows passage

What is dietary ADF associated with?

Digestibility

What generally happens to digestibility as ADF increases?

Digestibility decreases