1. Animal digestive systems

2. Why are digestive systems important?
It determines the quality of food an animal needs
and quantity of food an animal can take in.
How does a simple stomach digestion system work?
All animal digestive systems start with the mouth.
Teeth mechanically break down food into smaller pieces.
This process is called MASTICATION.
Saliva is secreted which contain enzymes with start the
Digestive process on carbohydrates. Lubricants also help
Animals swallow the food.
The tongue helps form the food so it will pass down the throat.
The pharynx is the common passage for the digestive and
Respiratory tract.
Esophagus connects pharynx to the stomach-tube like,
peristaltic movement

3. Stomach Small Intestines
Cardia- a flap valve located at the end of the esophagus prevents
Food from coming back up from stomach.
Stomach
Muscular movements break the food down mechanically
low PH of the stomach break food down chemically—mostly
Act on proteins.
Three areas of the stomach- Cardia, fundus, and pylorus. The
Pylorus valve, a sphincter valve, separates the stomach from the
Small intestines.
Small Intestines
Digestion continues with the aid of enzymes from the liver and
Pancreas.
Most of the absorption of nutrients takes place in the small
Intestines through the villi.
Chyme, partially digested food, is moved through the intestines by
Peristaltic movement.

4. Caecum appendix Large intestine Rectum
Found at the junction of the small and large intestine. In most mono-
Gastric animals it is non functional. The horse is a different story!
Large intestine
The major function of the large intestine is to recover water which
May contain some water soluble vitamins.
Rectum
Controls the release of solid wastes

5. Ruminant (poly gastric)
Much like the simple stomach digestive system except for the stomach.
Saliva of ruminants does not contain enzymes to help digest the starches.
Mature cows produce about 12 gallons of saliva per day
while sheep produce 2 gal.
Stomach
Divided into four parts
Rumen
Reticulum
Omasum
Abomasum

6. Protein in the rumen is converted to ammonia, organic acids and
Rumen - paunch
A large vat where the micro-organisms live that break down the high fiber food
Makes up to 80% of mature digestive system.
Protein in the rumen is converted to ammonia, organic acids and
amino acids. PH of the rumen should be between (acidosis)
Most amino acids synthesized by the rumen,
therefore, it is not necessary to supply large
quantities of amino acids in the ration.
The three types of rumen bacteria are
streptococci, lactobacilli and celluloytic bacteria.
Bacterial action in the rumen produces large
quantities (30-50 quarts per hour) of gas,
mainly CO2 and CH4.
This gas must be removed or the
animal will bloat.
The interior surface of the rumen forms numerous papillae that vary in shape and size from short and pointed to long and foliate

7. Bloat:
If a ruminant animal can not eructate (belch) or pas gas it builds
Up in the rumen.
Notice the location of the rumen to the lungs. An animal that dies
From bloating actually dies from suffocation!

8. Reticulum – hardware stomach
Located near the heart and diaphragm
Prevents heavy object; rocks, nails, fence post clips; from entering the
Digestive system.
Feed is moved back and forth between the rumen and reticulum by
regular contractions originating in the reticulum.
Magnets are sometimes
Placed in the reticulum
To keep metal objects
From moving, possibly
Piercing the heart or
Diaphragm.
This part of the stomach is also called
The honeycomb or tripe. In some
Ethnic groups it is considered a
Delicacy!
Reticular epithelium is thrown into folds
that form polygonal cells that give it a
reticular, honey-combed appearance.
Numerous small papillae stud the interior
floors of these cells.

9. The main function of the omasum is to
Omasum – many plies.
The main function of the omasum is to
Remove water from the food before it
Passes on to the Abomasum.
The material leaving the omasum is
60-70 percent drier than the material
entering it.
It is about the size of a basketball in a
Mature digestive system.
The inside of the omasum is thrown into
broad longitudinal folds or leaves
reminiscent of the pages in a book
(a lay term for the omasum is the 'book').
The omasal folds, which in life are packed
with finely ground ingesta, have been
estimated to represent roughly one-third
of the total surface area of the four stomachs.

10. Abomasum – true stomach
Digestion here is much the same as
it is in a monogastric animal.
Digestive juices are added to the
feed and it is moistened.
pH level of
The feed becomes highly fluid as it
passes into the small intestine.

11. Pusedorumenants – horse, rabbits.
These animals have an adapted
Simple stomach digestive system.
The ceacum is greatly enlarged and
This is where the micro-organisms
Live that break down the fibrous
Feed.
Horse saliva does not contain enzymes.
The stomach of the horse has less muscular activity than that of other species,
causing an increased tendency toward digestive disorders.
The stomach of a horse is smaller, compared to other species, in relation to the
size of the animal. Therefore, it is more desirable to feed horses in smaller amounts
at one time but provide more frequent feedings.
Horses do not have a gallbladder, therefore, bile is secreted continuously from the
liver to the duodenum.
Horses can use large amounts of roughage because of the presence of bacteria
in the cecum and colon. The large intestine makes up approximately 60% of the
total digestive tract.
Their digestive system is not as efficient as ruminant animal!