KEY
Study Guide
Topic # 3043
Digestion, Absorption and Feed Consumption
Anna Blight
Carbohydrates and Fats are the primary energy source in feed.
The amount of various nutrients in a feed, which can be absorbed from the digestive tract,
is referred to as digestibility.
The role of digestion is to reduce feed particles to molecules so they can be absorbed
into the blood and eventually support body functions.
Animals are classified as carnivores, omnivores, or herbivores depending on the type of
feed they normally eat.
Carnivores, such as cats and dogs, normally eat animal tissues (meat) as their source of
nutrients.
Cattle, horses, sheep, and goats are herbivores since they primarily consume plant
tissues.
Humans and pigs are examples of omnivores, who eat both plant and animal products.
Carnivores and omnivores are monogastric animals, meaning the stomach is simple in
structure, having one compartment.
Horses and rabbits are also monogastric animals.
Cattle, sheep, and goats are ruminant animals, since their stomach is complex in
structure and contains four compartments.
The four compartments of ruminant stomachs are called rumen, reticulum, omasum,
and abomasom.
The rumen is a large fermentation vat where bacteria and protozoa thrive and break
down roughages to obtain nutrients for their use.
The microorganisms from the rumen are later digested in the small intestine to provide
these nutrients for the animal’s use.
Ruminant animals and microorganisms mutually benefit each other.
In monogastric animals, enzymes aid in the digestion of feed.
The small intestine is the most important area for digestion and absorption of feed.
Volitile fatty acids are waste products of microbial fermentation of carbohydrates, and
are a major source of energy.
Digestion breaks down carbohydrates into simple starches and simple sugars, and fat
into fatty acids.
Starches are a very important source of energy for fermenting species.
Roughages are a source for starch in ruminant diets.