Animal Digestion
What are Nutrients?
parts of food which provide for growth,
maintenance, body functions
 Carbohydrates (CHO)
 Fats
 Proteins
 Vitamins
 Minerals
 Water

What is a Ruminant?
Animals with more than one stomach
 Chew their cud (re-chew food)
 Cows, sheep, goats
 Cows have four stomachs
 Alf has eight stomachs

Why don’t cattle need as much B
vitamins?
Microorganisms in the stomach of the cow
make their own B vitamins
 Can also make some proteins if given the
right kind of Nitrogen

NonRuminants
Foragers: Horse, rabbit
 NonForagers: pig, poultry

How much to feed?
Depends on function of animal
 Pregnant, Lactating, Working, Growing
 How often to feed
Depends on stomach size & rate of
metabolism
Stomach size is relavant to amount of
feed fed
Mink = 4-6 times/day, Cows = 1-2 /day

What foods give energy?
Carbohydrates (starch & cellulose) & Fats
 Fat = 2 1/2 times energy of CHO
 Energy is major part of a feed ration
 Up to 90% of a ration for a steer
 Measured in Kilocalories or TDN (Total
Digestible Nutrients)

What are Proteins?
Used to build muscle, body tissue
 Made of amino acids
 Ruminants can make some proteins
 Simple Stomachs need specific amino acids

What are Minerals?
Natural elements which regulate certain
body functions
 Na, Ca, P, Fe, Cu, K, Mn, Mg, Zn, Mo, Se,
I, Co
 Most are trace minerals

What are vitamins?
Compounds responsible for certain
functions
 Fat Soluable = A, D, E, K
 Water Soluable = B, C

What are additives?
Antibiotics: disease prevention
 Coccidiostats: control parasites
 Xanthophyll: makes egg yolks yellow
 Hormones: increase growth
 Tranquilizers: calm nerves (cattle, turkeys)
 Antioxidants: prevent feed from getting rancid
 Pellet Binders: keep in pellet form
 Flavoring Agents: make taste better

Livestock Feeding
Roughage = high fiber, low energy
 Concentrate = low fiber, high energy

How is a ration balanced?
Pearson square: balance a ration using any
two ingredients for one nutrient
 How much Soybean Meal (44% Protein)
should be mixed with Barley (13% Protein)
to get a mixture that is 16% protein?

Pearson Square
Soybean
Meal 44%
SBM = 3 parts
16%
Barley 13%
Barley = 28 parts
Total Parts = 31
Pearson Square
Soybean Meal = 3 parts
 Barley = 28 parts
 Total Parts = 31
 Soybean Meal = 3/31 or 10%
 Barley = 28/31 or 90%
 If mixing a ton (2000#) SBM = 200#,
Barley = 1800#
