Ruminant Digestion

Objectives Describe the ruminant digestive system. 1 Stomach, 4 Compartments Functions How they change with maturity Identify what kinds of animals have what type of digestive systems

What animals are ruminants?

Ruminant Digestive Tract Animals with four stomach compartments through which digestive processes occur Advantages: Bacteria or “microbes” in the rumen can break down cellulose – main component of cell wall in plants Can eat forages (alfalfa and other feeds) as well as grasses that are lesser quality

Where does it all fit?

Ruminant Digestion – Close Up

Ruminant Compartments 1. Rumen Large “fermentation” vat Where all the microbes are Break down of cellulose Causes build-up of gases, and animals burp… Animals will regurgitate food and re-chew it – an animal that is chewing their “cud” Accounts for 10% of digestion at birth and 80% at maturity

Inside has papilli – small rounded projection

Bloat

Eight week old calf’s rumen Developing healthy papilli

Rumen Development Undeveloped Rumen Developed Rumen

Importance of Diet to Rumen Development (12 Weeks of Age) Milk, hay and grain Milk and hay

Ruminant Compartments 2. Reticulum Contents from the rumen often mix back and forth with the reticulum Often called the “honeycomb” due to its appearance Accounts for 10% of digestion at birth and 5% at maturity

Cow Magnets

Ruminant Compartments 3. Omasum (O-mace-um) Very little if any digestion occurs here Many layers of tissue in this compartment, also called the “book” Accounts for 10% of digestion at birth and 8% at maturity

Ruminant Compartments 4. Abomasum(Ab-O-Mace-Um) Known as the “true stomach” because it is closest to our stomach Secretes enzymes and acids to break down nutrients Accounts for 70% of digestion at birth and 7% at maturity

Size of Ruminant Stomach Compartments Adult, % Newborn, % Rumen 55 29 Reticulum 7 6 Omasum 24 14 Abomasum 51

Label the Stomachs and the Pathway of Digestion

Fistulated Cow

What is this?

Review Describe and identify the compartments of the ruminant digestive system. What are they? Which does the food go to first? Which is most used in adult animals?