1. Ruminant Digestion

2. 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

3. What animals are ruminants?

5. 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

6. Where does it all fit?

7. Ruminant Digestion – Close Up

8. 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

9. Inside has papilli – small rounded projection

10. Bloat

11. Eight week old calf’s rumen
Developing healthy papilli

12. Rumen Development
Undeveloped Rumen
Developed Rumen

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

14. 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

16. Cow Magnets

17. 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

19. 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

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

21. Label the Stomachs and the Pathway of Digestion

23. Fistulated Cow

24. What is this?

26. 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?