Show Your Work Name _____________________________
Digestion Problem Set
1. Calculate % total tract digestibility of the following feed components on a dry matter basis:
Dry Matter
Crude Protein
NDF
Energy
Use the information below:
Diet is 85% dry matter
On a Dry Matter basis, diet contains: 14% Crude Protein
60% Neutral Detergent Fiber
4 Mcal Gross Energy/kg
Feces are 40% Dry Matter
On a Dry Matter basis, feces contains: 26% Crude Protein
66% NDF
Gross Energy of 2.45 Mcal/kg
Animal Data 300 kg steer
As is intake = 7.2 kg/d
As is fecal output = 6.25 kg/d
2. Estimate total tract digestibility of Dry Matter and Crude Protein of a 400 kg heifer eating a
corn silage based diet.
On a DM basis feed contains 9% crude protein. You’ve added Cr2O3 to diet so diet
Cr is .2%.
On a DM basis, fecal grab samples contain 12% CP and .9% Cr.
3. a. Calculate pre-intestinal digestibility of DM (%) if:
Feed has .15% Cr (from Cr2O3)
Duodenal sample has .35% Cr.
b. If feed intake is 8 kg of DM/d, how much DM reaches the duodenum daily?
