Nutrition: Constituents, Analyses, and Terminology

Question 1

Moisture

Answer 1

g/kg, dry to constant weight

Question 2

Ash

Answer 2

g/kg, ignite at 550*C

Question 3

Crude protein

Answer 3

Calculated from N content of feed, Nx6.25

Question 4

Ether extract

Answer 4

Oil: lipids, organic acids, alcohols, and pigments

Question 5

Crude fiber

Answer 5

Residual food from ether extract boiled in acid and alkali

Question 6

Nitrogen-free extracts

Answer 6

1000 minus (moisture+ash+CP+EE+CF)

Question 7

Dry matter (DM)

Answer 7

Dry to constant weight

Question 8

Organic matter (OM)

Answer 8

DM-ash

Question 9

Crude protein

Answer 9

Calculated from N content of feed, assumes protein content of 16% N, so Nx6.25

Question 10

Neutral detergent fiber (NDF)

Answer 10

Plant cell wall material
Fiber insoluble in neutral detergent
Residue contains CW materials: lignin+cellulose+hemicellulose

Question 11

Acids detergent fiber (ADF)

Answer 11

Fiber insoluble in acid detergent

Residue contains CW material: lignin+cellulose

Question 12

What happens in terms of carbohydrates as the plant matures?

Answer 12

Increase in structural material, increase in lignin, decrease in nutritive value and digestibility

Question 13

Non-structural carbohydrates

Answer 13

Constitute storage carbs

Ex. Fructan and starch

Question 14

Fructan

Answer 14

Major storage CHO of temperate grasses
Soluble in H2O
Increase in molecular weight=decrease in degradability

Question 15

Factors affecting NSC accumulation

Answer 15

Genetics 
Part of plant (stem >leaves)
Season (early spring=inc growth, dec NSC; late spring/summer= dec growth, inch NSC) 
Time of day 
Environmental and management factors