1. Animal Science
Digestive Systems

2. Types of Digestive Systems
Hind Gut Fermentors
Avian
Monogastrics
Ruminants
Chickens
Pigs
Beef Cattle
Dairy Cattle
Horses
Sheep
Goats
Turkeys
Dogs
Rabbits
Ostrich
Deer
Cats

3. Monogastrics One compartment stomach Cannot digest grass or hay
Secretes acid and enzymes that digest food
Need high energy diets
Humans
Pigs
Cats
Dogs

4. Small intestine (jejunum, ileum)
Digestive Tract - Pig
Esophagus
Stomach
Liver
Pancreas
Duodenum
Small intestine (jejunum, ileum)
Cecum
Colon
Rectum

5. Organs of Digestive System
Monogastrics
Mouth
Mechanical breakdown of foodstuffs by chewing
Saliva added as a lubricant and begins digestion.
Esophagus
Tube connecting the mouth to the stomach.

6. Organs of Digestive System
Monogastrics
Stomach
Enzymatic digestion of proteins begins.
Food reduced to liquid form.
Liver
Center of metabolic activity in the body.
Provides bile salts to small intestine (needed for digestion and absorption of fats).

7. Organs of Digestive System
Monogastrics
Pancreas
Provides digestive enzymes to the small intestine to help in digestion of fats, carbohydrates, and proteins.
Small Intestine
3 sections – duodenum, jejunum, ileum
Site of final stages of chemical enzymatic digestion.
Where almost all nutrients are absorbed.

8. Organs of Digestive System
Monogastrics
Large Intestine
3 sections – cecum, colon, rectum
Site of water absorption
Feces formed.

9. Avian Considered monogastric One compartment stomach
Chickens
Considered monogastric
One compartment stomach
Cannot digest grass or hay
Secretes acid and enzymes that digest food
Need high energy diets
Turkeys

10. Small intestine (jejunum, ileum)
Digestive Tract - Poultry
Esophagus
Crop
Proventriculus
Gizzard
Liver
Gall bladder
Cecum
Cloaca
Large intestine
Small intestine (jejunum, ileum)
Pancreas
Duodenum

11. Organs of Digestive System
Avian
Beak
No lips, no teeth, and no chewing.
Crop
Pocket of the esophagus that provides storage for consumed food.
Food is moistened and softened

12. Organs of Digestive System
Avian
Proventriculus
Glandular stomach adds digestive juices
Gizzard
Grinds and breaks up food.
May contain grit (small stones) eaten by bird.

13. Organs of Digestive System
Avian
Cloaca
Common chamber into which the digestive, urinary, and reproductive tracts open.

14. Ruminants Most herbivores Fore-gut fermentation vat for grass and hay
Four compartment stomach (not four stomachs)
Chews cud
Deer
Beef Cattle
Dairy Cattle
Sheep
Goats

15. Digestive Tract - Cattle
Esophagus
Rumen
Omasum
Reticulum
Abomasum
Pancreas
Liver
Gall bladder
Cecum
Small intestine
Large intestine
Rectum

16. Organs of Digestive System
Ruminants
Mouth, esophagus, liver, pancreas, small intestine, and large intestine have functions similar to monogastrics.
Stomach
Multi-compartmented stomach – rumen, reticulum, omasum, abomasum.

17. Parts of the Ruminant Stomach
Rumen:
Largest compartment
“Fermentation Vat”
Digests forages
Rumen Capacity
Species
Normal capacity
Maximum capacity
Cow (1000 lb)
25-30 gallons
55-60 gallons
Ewe (150 lb)
3-5 gallons
5-10 gallons

18. Parts of the Ruminant Stomach
Rumen (continued):
Lined with millions of papillae (short projections on wall of rumen) needed for absorption.
“Shag carpet” appearance

19. Parts of Ruminant Stomach
Reticulum:
Contains microorganisms (like the rumen).
Catches non-digested material.
“The Honeycomb”
Catches and holds hardware consumed by animal.
Hardware can be removed with rumen magnet.

20. Parts of Ruminant Stomach
Omasum:
“The Book”
A heavy, hard organ with a lining that has many folds
Function not well understood.
Filters large particles back to reticulum
Absorbs water

21. Organs of Digestive System
Monogastrics
Abomasum:
“True Stomach”
Similar to monogastric or human stomach
Digests grains and breaks down proteins

22. Hind-gut Fermenters One simple, glandular stomach
Hind-gut fermenter (Cecum) digests plant fiber
Must graze often
Must have fiber (grass or hay)
Ostrich
Horses
Rabbits

23. Digestive Tract - Horse
Esophagus
Stomach
Duodenum
Small intestine
Cecum
Large colon
Small colon
Rectum

24. Organs of Digestive System
Hind-Gut Fermentors
Mouth, esophagus, stomach, liver, pancreas, and small intestine have similar functions as compared to monogastrics.
Cecum
Large and complex compared to monogastrics and ruminants.
Cecum similar to rumen in ruminants
Fermentation vat
Microbes to break down fiber

25. Small intestine (jejunum, ileum)
Digestive Tract Type?
Liver
Pancreas
Cecum
Rectum
Esophagus
Stomach
Duodenum
Colon
Small intestine (jejunum, ileum)

26. Small intestine (jejunum, ileum)
Digestive Tract Type?
Gall bladder
Liver
Cecum
Gizzard
Esophagus
Crop
Proventriculus
Cloaca
Pancreas
Large intestine
Duodenum
Small intestine (jejunum, ileum)

27. Digestive Tract Type? Small intestine Rumen Rectum Pancreas Omasum
Esophagus
Large intestine
Reticulum
Abomasum
Cecum
Liver
Gall bladder

28. Digestive Tract Type? Small intestine Rectum Cecum Esophagus Stomach
Small colon
Duodenum
Large colon