Physical form
length
cm
Grass hay
Grass silage
Corn silage
Alfalfa hay
Alfalfa silage
% of NDF that is physically effective
Long
100
95
Coarse chopped
4.8 to 8
95
95
90
85
Med
chopped
1.2 to 2.0
90
90
85
85
80
Fine chopped
0.3 to 0.5
85
85
80
80
70
Ground
0.15 to 0.25
40
40
Mertens (1997)