Lecture 2 Part 2

Question 1

non fibrous

Answer 1

starches and sugars

Question 2

fibrous

Answer 2

cellulose

Question 3

benefits of van soest fiber analysis

Answer 3

-useful
- accurate
- evaluating type of carbs

Question 4

cell contents

Answer 4

• digestible fraction of CHO, protein, lipid, and some ash
• sugar and starch
• protein
• lipids

Question 5

cell wall

Answer 5

structural fiber and lignin
- cellulose
- hemicellulose
- lignin

Question 6

NDS

Answer 6

neutral detergent solubles
- cell contents

Question 7

NDF

Answer 7

Neutral detergent fiber
- cell wall

Question 8

cell contents vs cell wall

Answer 8

cell contents are the stuff that is easy to digest while the cell was is stuff that is not easy to digest

Question 9

what do microbes posses to digest cellulose

Answer 9

enzymes

Question 10

what do cellulose and hemicellulose make up

Answer 10

carbs

Question 11

lignin

Answer 11

• structure and support
• doesn’t provide nutrients
• not digestible for microbes

Question 12

as age increases cell wall becomes

Answer 12

• tougher/thicker because lignin and NDF increases while digestibility decreases

Question 13

van soest method

Answer 13

• forage
• digest with neutral detergent
• cell contents removed and hemicellulose, cellulose and lignin remain
• digest with acid detergent (full picture)
• hemicellulose removed and cellulose and lignin remain
• digest with 72% sulfuric acid
• cellulose removed and lignin remains

Question 14

why in the van sest method is there a step of digest with 72% sulfuric acid

Answer 14

only way to separate cellulose and lignin

Question 15

what is under the category of NDF

Answer 15

• cellulose
• hemicellulose
• lignin
• silica
• heat damaged proteins

Question 16

silica

Answer 16

• common in soils with a lot of sand
• could be potential contaminant
• increase NDF values

Question 17

heat damage proteins

Answer 17

• change shape and structure
• may not be chemically analyzed the same way
• overestimate value of NDF

Question 18

ADF

Answer 18

acid detergent fiber

Question 19

what is ADF

Answer 19

• lignin and cellulose
• stuff that is hard to digest
• boil NDF in acid to remove hemicellulose

Question 20

is lignin a carb

Answer 20

no, it’s a structural filler
- nonnutritive component of feedstuff

Question 21

summary of fiber analysis

Answer 21

• NDF: cell wall components
• NDS: cell content & easy to digest
• ADF: cell wall components
• ADL: lignin portion of ADF

Question 22

what does van soest explain

Answer 22

nutritional responses in terms of feed digestibility and intake

Question 23

which is better CF or Van Soest

Answer 23

Van Soest

Question 24

what does NDF predict

Answer 24

voluntary feed intake
- higher= less feed intake

Question 25

what does ADF predict

Answer 25

- forage digestibility - lower= more digestible - decrease = decrease in cellulose

Question 26

what is van soest more relative to

Answer 26

high fiber feeds

Question 27

non fiber carbohydrate

Answer 27

- from van soest NFC= 100-(NDF+CP+CFat+Ash) - highly digestible carbs

Question 28

near infrared analysis (NIR)

Answer 28

- sample dried & ground - expose sample to Near Infrared Light Source - reflect infrared radiation measured - each organic component absorb and reflect near infrared differently

Question 29

benefits of NIR

Answer 29

- extremely detailed - potential to provide instantaneous results

Question 30

NIR challenges

Answer 30

- has to be calibrated based on wet chemistry - very costly - not recognized as an official analysis

Question 31

specialized methods of feed analysis

Answer 31

- bomb calorimetry - amino acid analysis (chromatography) - gas-liquid chromatography (fatty acids) - dumas combustion method (non metallic elements)

Question 32

biological methods of feed analysis

Answer 32

test what is actually happening in animal - in-situ - digestibility trials - passage rate trials

Question 33

what procedure is also considered Kjeldahl Procedure and why?

Answer 33

Crude Protein because it measures the nitrogen in material - Kjeldahl procedure also was a method for measuring nitrogen