Ruminant Digestive System

Ms. Zubiate
What is a ruminant animal ?
animal that has
a digestives
system with 1
containing 4
Other characteristics:
No upper incisors (teeth)
called a dental pad.
Chews cud (soft mass of
already chewed food)
that is brought back up
through the esophagus.
All ruminants are
herbivores, meaning they
only eat plant matter.
Can you think of any ruminant
Pathway of food through
digestive system.
 1.
 2. esophagus
 3. rumen
 4. back to mouth for “chewing of cud”
 5. Reticulum
 6. omasum
 7. abomasum
 8. small intestine
 9. Large intestine
Getting Started!
 1.
Using prehensile organs (lips & tongue)
the animal take food into its mouth where
it is then broken down using the teeth.
The esophagus
 2.
After the food is
broken down into
smaller particles it is
swallowed and passes
through the esophagus
using muscle
contractions known as
Muscle contraction is called peristalsis:
The rumen
 3.
The largest compartment of the
ruminant stomach is the rumen. This is
where the food that the animal has been
taken in is mostly fermented, it also houses
the bacteria, protozoa, and fungi that
aids in the breaking down of food.
Microbes in the rumen are what
break up the plant matter and
convert it to energy that the
animal can use.
Fermentation also produces large
amounts of gas.
Chewing cud
Food that is stored in the rumen is
regurgitated back up through esophagus
to be re-chewed in the mouth. This is know
as “chewing cud”. Food can be rechewed more than one time.
The food that is regurgitated back into the
mouth is known as a bolus.
Once the food has been broken down
enough it will then move onto the next step
in the digestion process of being
swallowed, moved through the esophagus
then back into the rumen.
The reticulum
4. Once food is broken
down small enough it
will travel from the
rumen to the reticulum.
The reticulum is the
honeycomb shaped on
the inside and is very
The reticulum can trap
foreign objects that
should not have been
eaten in the first place,
such as hardware.
The Omasum
5. Food enters the
omasum after leaving
the reticulum.
The omasum acts as a
filter to absorb water
and nutrients from what
has not been digested
The omasum resembles
an open book because
of its “pages” texture.
6. Once leaving the
omasum the rest of the
plant matter will enter
the abomasum.
The abomasum is also
known as the true
In the abomasum
gastric juices,
hydrochloric acid, and
digestive enzymes break
plant matter down into
its most basic molecular
components so that the
walls of the intestines
can absorb them.
Small intestine
From the abomasum
the plant matter will
then travel to the
small intestine.
Here, it is exposed to
enzymes from the
pancreas and
intestinal walls, and
bile from the liver.
Dietary protein,
starch, sugars, and
fats are all completely
digested here to enter
the bloodstream.
Small intestine
large intestine
Following the small
intestine any remaining
plant matter will pass
into the large intestine.
This is the second site of
fermentation (after the
rumen) where excess
water is reabsorbed.
The large intestine is the
final site of the
large intestine
gastrointestinal tract
(GIT), and will hold
feces until it is expelled
through the anus.

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