Ruminant Digestive System

Introduction

• Ruminants: Large group within hoofed animals (artiodactyls).
• Important in food chains globally due to unique digestive systems.
• Examples: Cows, sheep, goats.
• Diet: Forages and roughages.

Digestive System Overview

• Runs from mouth to anal canal.
• Functions: Grind food, digest, absorb nutrients, eliminate waste.
• Key Organs: Mouth, esophagus, four-chambered stomach, small intestine, large intestine.
• Auxiliary Organs: Pancreas and gallbladder (assist but not part of primary system).

Digestion Process

Mouth

• Large molars and premolars for grinding.
• Increases saliva production for chemical breakdown and buffering.
• Feed and saliva form a mixture that is swallowed.

Esophagus

• Muscular tube using peristalsis for food movement.
• Bidirectional: Can send food back up (cud chewing).

Stomach

• Four chambers: Rumen, reticulum, omasum, abomasum.

Rumen

• Location: Left side of body.
• Functions: Storage and fermentation.
• Contains saliva and gut microbes for fermentation.
• Mechanical and chemical digestion through muscle contractions and microbial action.
• Layers: Gases (top), today's food (middle), yesterday's food (bottom).
• Nutrient absorption through papillae.
• Bi-directional with reticulum.

Reticulum

• Alias: Honeycomb.
• Functions: Transitional chamber, nutrient absorption, collects smaller food pieces.
• Regurgitates cud if needed.
• Rarely referred to as reticulorumen along with rumen.

Omasum

• Varies in size by animal; large in cattle.
• Function: Reabsorbs water and some nutrient absorption.
• Also known as tripe when harvested.
• Lined with tissue folds (like book pages).

Abomasum

• Alias: True stomach.
• Produces acidic gastric juices and enzymes for further breakdown.
• Small particle size facilitates efficient gastric juice action.

Small Intestine

• Main site for nutrient absorption.
• Lined with villi to increase surface area.
• Enzymes from pancreas and gallbladder assist digestion.
• Nutrients pass into blood and lymph systems.
• Feed moved via peristalsis.

Large Intestine

• Absorbs remaining water.
• Has microbes for additional nutrient extraction.
• Waste stored in rectum before being passed out as stool.