ANS 231 Module 1

What is proximate analysis

General series of analyses that relates to the classes of nutrition

Used 100 years ago and today

Set of terms related to proximate analysis

Crude protein

Crude fat

Crude fiber

Crude ash

What is crude protein

Measure of N content of a feed ingredient multiplied by 6.25

Approximates amount of protein in a sample

What is crude fat

Measure of components in a feed sample that can be extracted with an organic solvent like diethyl ether

Approximates fat content in a sample

What is crude fiber

Estimate of fiber content (includes only some fiber components)

What is crude ash

Material remaining when a feed sample is completely oxidized in a muffle furnace

Contains the mineral component of sample

What is another common analysis

Detergent analysis system

What is the detergent analysis system

Describes the fibrous components of the plant more completely than crude fiber

2 main fractions of detergent analysis system

Neutral detergent fiber

Acid detergent fiber

What is neutral detergent fiber (NDF)

Portion of fiber insoluble in neutral detergent (roughly equivalent to cell wall fraction)

Includes cellulose, hemicellulose, and lignin

What is acid detergent fiber (ADF)

Portion of fiber that is insoluble in acid detergent

Includes cellulose and lignin (hemicellulose is soluble in acid detergent)

What set of terms describe energy value of a feed? Where do the values come from

Gross energy (GE): measured in lab

Digestible energy (DE): from studies with animals

Metabolizable energy (ME): from studies with animals

What is gross energy

Total potential energy in feed ingredient

What is digestible energy

Energy remaining after energy excreted in feces subtracted from gross energy

Gives an idea of how much energy animal absorbs from feed

What is metabolizable energy

Energy remaining after energy excreted in feces, urine, and gas (methane)

2 major components to divide materials into

As fed (AF) basis: the feed as it is fed to the animal (dry matter + water)
100% dry matter (DM) basis: the feed not including the water, includes all the nutrients in the dry matter

Calculation for dry matter percentage

(weight of dry sample/weight of As fed sample)  x  100

Is the amount of feed greater in dry matter or as fed

As fed because it includes water

Is nutrient concentration greater in dry matter or as fed

Concentration of a nutrient is greater when expressed on a dry matter basis.  This is because the water has been removed but the amount of the nutrient is the same.  Therefore, it is concentrated in the dry matter and is a greater percentage of the total

Can you compare nutrient concentration of feedstuffs on dry matter basis

Yes if percent DM is the same

Feed composition graphs for reference

Have to know these conversions

1 kg = 2.2 lbs                   

1 kg = 1,000 g               

1 ton = 2,000 lbs             

1 metric ton = 1,000 kg

1 lb = 0.454 kg  

1 lb = 454 g

1 lb = 16 oz

1 kcal  = 1000 calories

1 Mcal = 1,000 kilocalories