KEY
Note Taking Guide
Topic # 3043
Digestion, Absorption and Feed Consumption
Anna Blight
Carbohydrates and Fats are:
 the primary energy source
Carbohydrates:
 contain carbon, hydrogen, and oxygen
 broken down into simple sugars and starches
 Sugars and starches are a very important source of energy.
 Roughages are an important source of starch in ruminant diets
 Monogastrics use concentrates as a source of carbohydrates
Carbohydrates are:
 High in energy
 Low in fiber
 Highly digestible
Fats are:
 Primary energy source
 Contains carbon, hydrogen, and oxygen
 Digestion breaks down into fatty acids
 2.25 times more energy per pound than carbohydrates
Digestion and Absorption
 Digestion breaks food particles down into molecules
 Molecules can be absorbed into the blood and eventually support body functions
 Digestibility refers to the amounts of nutrients in a feed, which can be absorbed
by the body from the digestive tract
 Ruminants or monogastrics
Ruminants:
 Cows, goats and sheep
 Ruminate = chew cud
 re-chew a regurgitated bolus of feed
 Has a complex stomach consisting of more than one compartment
 The four compartments of a cow stomach are called: rumen, reticulum, omasum
and abomasums
 The rumen is a large fermentation vat where bacteria and protozoa
(microorganisms) thrive and break down roughages for their own use
 The animal has a mutualistic relationship with these microorganisms
 Cattle can synthesize B – complex vitamins by the microorganisms in the gut
 Also can make some proteins if given the right kind of nitrogen
 Later these microorganisms are digested in the small intestine to provided
nutrients for the animals use
Fermentation process:
 Microbial fermentation of carbohydrates produces volatile fatty acids as waste
produces
 Animal uses volatile fatty acids as a major energy source
 Also produces methane gas and some carbon dioxide
Monogastrics:
 Pigs, horses, poultry and humans
 Simple stomach, one compartment
 Enzymes present in salivia and in the stomach aid in digestion
 Carbohydrates break down into simple starches and sugars
 Proteins to amino acids
 Fats to fatty acids
 Monogastrics cannot significantly synthesize B – complex vitamins or amino
acids
 Small intestine receives products of digestion
 Small intestine is the most important area for digestion and absorption of feed