1. DIGESTION
SYSTEM
Bargfrede

2. Monogastric (non ruminate)
Pigs
Chickens
Turkeys
Dogs
Cats
Bargfrede

3. RUMINANTS
CATTLE
GOATS
SHEEP
DEER
Bargfrede

4. HIND GUT FERMENTORS
HORSE
RABBITS
OSTRICH
Bargfrede

5. Small intestine (jejunum, ileum)
monogastrics
Esophagus
Stomach
Liver
Pancreas
Duodenum
Small intestine (jejunum, ileum)
Cecum
Colon
Rectum
Bargfrede
mouth > esophagus > simple stomach > small intestine (duodenum, jejunum, ileum) > large intestine > rectum > anus

6. Mouth Esophagus Monogastrics
Mechanical breakdown of foodstuffs by chewing (reduces particle size, increases surface area for action of enzymes).
Saliva added as a lubricant and, in some species, contains amylase to begin starch digestion.
Esophagus
The portal to the stomach
Food passes quickly through the esophagus by PERISTALSIS into the stomach.
Peristalsis – a process by which muscular contractions propel food material through the digestion tract.
Bargfrede

7. Monogastrics Stomach Liver Pancreas
Enzymatic digestion of proteins begins.
Foodstuffs reduced to liquid form.
Liver
Center of metabolic activity in the body.
Major role in digestive process is to provide bile salts to small intestine (needed for digestion and absorption of fats).
Pancreas
Provides a potent mixture of digestive enzymes to the small intestine to help in digestion of fats, carbohydrates, and proteins.
Bargfrede

8. Monogastrics Small Intestine (duodenum, jejunum, ileum)
Site of final stages of chemical enzymatic digestion.
Where almost all nutrients are absorbed.
duodenum (first part of the small intestine)
Bile and pancreatic secretions enter here
jejunum (second part of the small intestine)
Absorption of nutrients
ileum (third part of the small intestine)
To split food molecules and absorb nutrients
Bargfrede

9. Monogastrics Large Intestine
Site of water absorption from G.I. tract.
Bacterial fermentation occurs (production and absorption of volatile fatty acids).
Somewhat limited in monogastrics
Feces formed
Remember: the large intestine is shorter in length than the small intestine but of greater diameter and volume.
Rectum
The last part of the large intestine where feces is stored before going to the anus.
Anus
Undigested feces that has passes through the body cavity is secreted.
Bargfrede

10. Small intestine (jejunum, ileum)
monogastrics
Esophagus
Crop
Proventriculus
Gizzard
Liver
Gall bladder
Cecum
Cloaca
Large intestine
Small intestine (jejunum, ileum)
Pancreas
Duodenum
Bargfrede
mouth > esophagus > crop > proventriculus > gizzard >
small intestine > ceca > large intestine > cloaca > vent

11. Beak Esophagus Crop monogastrics No lips, no teeth, and no chewing
The portal to the stomach
Crop
Out-pocketing of the esophagus that provides storage pack for consumed food.
Saliva assist the foodstuffs tomoistened and softened (little if any digestion).
Crop
Bargfrede

12. monogastrics Proventriculus Proventriculus
Glandular stomach where the first significant amount of digestive juices are added.
This part is also referred to the glandular stomach due to it containing hydrochloric acid (HCL) and digestive enzymes.
Proventriculus
Bargfrede

13. Gizzard monogastrics Gizzard
A muscular organ used to grind and break up food.
May contain grit (small stones) eaten by animal.
Most of the fine particles of feed are not retained and move rapidly into the small intestine.
Gizzard
Bargfrede

14. monogastrics Small intestine Large intestine Cloaca Vent
Major part of digestion and absorption.
About 5 feet in length.
Large intestine
Only 4-5 inches
Digestion here happens quickly
Cloaca
Large intestine joins the vent
Serves as a receiving area for the egg in hens.
Vent
The external opening of the cloaca which allows both
egg and waste material to be expelled from the body
Bargfrede

15. RUMINANTS
Esophagus
Rumen
Omasum
Reticulum
Abomasum
Pancreas
Liver
Gall bladder
Cecum
Small intestine
Large intestine
Rectum
Bargfrede
mouth > esophagus > rumen (regurgitate, rechew, reensalivated, reswallowed) > reticulum> omasum> abomasum > small intestine > cecum > large intestine > rectum > anus

16. Ruminant
Mouth, esophagus, small intestine and large intestine have functions similar to monogastrics.
Stomach
Structure and function of the stomach is the major difference between monogastrics and ruminants.
Multi-compartmented stomach – rumen, reticulum, omasum, abomasum.
Bargfrede

17. Ruminant Rumen (regurgitated, rechewed, reensalivated, reswallowed)
Lining of the rumen
Rumen (regurgitated, rechewed,
reensalivated, reswallowed)
The largest of the 4 compartments in the
stomach, predominantly on the left side of the body cavity.
Active microbial digestion occurs.
Covered with papillae to increase the surface area
Rumen saturated with gases and in constant motion.
Regurgitation: first step in rumination
large quantities of roughage are consumed and are chewed just enough to swallow
after swallowing, regurgitation (“cud chewing”) takes place, food is re-chewed and the process continues
till the food is small enough to travel to the reticulum,
the next step in digestion.
Bargfrede

18. Ruminant Reticulum Houses microorganisms
Catches hardware (ingested by animal)
Provides additional area for fermentation.
As fermentation by microorganisms proceed and feedstuffs are digested, smaller and more dense material is pushed into the reticulum (from which it along
with microbe-laden liquid is ejected into
the omasum).
Lining has a honeycomb structure.
Hardware can be removed with a rumen magnate.
Open to the rumen
Bargfrede

19. Omasum A heavy, hard organ with a lining that has many folds (leaves).
Ruminant
Omasum
A heavy, hard organ with a lining that
has many folds (leaves).
Function not well understood
Believed to produce a grinding action on foodstuffs.
May absorb residual
VFA’s and bicarbonate.
Absorbs mostly water
Bargfrede

20. The true, glandular stomach.
RUMINANT
Abomasum
The true, glandular stomach.
Secretes acids and functions very similarly to monogastric stomach.
Unique feature is that it secretes lysozyme.
Enzyme that efficiently breaks down bacterial cell walls.
Needed to break down the
large quantities of bacteria
that pass from the rumen.
Bargfrede

21. Ruminant Small intestine Cecum enzymatic digestion and absorption
Functions of the small intestine: digestion of proteins, carbohydrates, and fats; absorption of the end products of digestion
duodenum
jejunum
ileum
Cecum
Some microbial fermentation
Bargfrede

22. HIND GUT FERMENTOR
Esophagus
Stomach
Duodenum
Small intestine
Cecum
Large colon
Small colon
Rectum
Bargfrede
mouth > esophagus > stomach> small intestine > cecum > large intestine (small colon, large colon)> rectum > anus

23. HIND GUT FERMENTOR
Mouth, esophagus, stomach and small intestine have similar functions as compared to monogastrics.
Small and large colon (large intestine)
The large intestine of hind gut fermentors is analogous to the rumen in ruminants
Microbes digest structural carbohydrates (cellulose, hemicellulose) and soluble carbohydrates that escape digestion in small intestine to Volatile Fatty Acids (VFA’s).
VFA’s absorbed from large intestine and utilized by the animal.
Microbial protein produced in large intestine is wasted (only very limited absorption from large intestine).
Bargfrede

24. Digestive System Comparisons
Function
Monogastric
Ruminants
Hind Gut Fermentors
Digest and extract energy from cellulose
Very limited
(large intestine)
Yes
(rumen/reticulum)
Utilize dietary sugar sources directly
(absorbed as glucose) No
(fermented to VFA’s)
Utilize protein from feeds directly
Limited
(most converted to microbial protein)
Utilize fat from feeds directly
Some
(most fermented to VFA’s)
Utilize microbial protein
(60-80% of AA from microbes)

25. Digestive Tract Capacities
Sheep/Goats
Cattle
Swine
Horses
Rumen
5-10 gal
55-60 gal
----
Reticulum
1.5 qt
3-4 gal
Omasum
1 pt
1-2 gal
Abomasum
Stomach
2 gal
2-3 gal
Small intestine
2.5 gal
17-18 gal
12-15 gal
Small intestine length
85-90 ft
130 ft
60 ft
70 ft
Large intestine
1.5 gal
10 gal
3 gal
30-35 gal

26. Bargfrede

27. Bargfrede

28. Bargfrede