Animal Science Digestive Systems

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

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

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

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.

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).

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.

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

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

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

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

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.

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

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

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

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.

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

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

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.

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

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

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

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

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

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

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

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

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