1. Welcome Class!

2. Objectives Describe the ruminant digestive system.
1 Stomach, 4 Compartments
Functions
How they change with maturity
Identify the primal cuts of beef and the retail cuts of each.
Describe the USDA beef grades.
Identify common injection sites as it deals with beef cuts.

3. 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

4. Where does it all fit?

5. Ruminant Digestion – Close Up

6. 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

7. Inside has papilli – small rounded projection

8. Bloat

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

10. Rumen Development
Undeveloped Rumen
Developed Rumen

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

12. 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

14. Cow Magnets

15. 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

17. 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

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

19. Label the Stomachs and the Pathway of Digestion

21. Fistulated Cow

22. What other animals are ruminants?

23. What is this?

25. Beef Carcass Cuts 9 primal carcass cuts on beef animal.
Retail cuts come from primal cuts.
Page 5 of Handout:
Work in groups of two and label your handout with the primal cuts

26. 9 Primal Cuts – Word Bank Round Chuck Brisket Sirloin Flank Rib Plate
Short Loin
Shank (done for you)

30. USDA Beef Grades Quality grades refer to characteristics of meat
Tenderness
Juiciness
Flavor
Top three grades are often found in restaurants and grocery stores

31. USDA Beef Grades – page 2 Prime: Choice: Select:
Most marbling – small flecks of fat throughout the meat
Generally in finer restaurants and higher priced
Choice:
Sufficient amount of marbling, cheaper than prime
Select:
Less marbling than choice, leaner

32. Marbling

33. Prime

34. Choice

35. Select

36. Injections Subcutaneous (Sub Q) – under the skin but not in the muscle
Intramuscular (IM) – directly into the muscle
Intravenous (IV)– into a vein

38. Sub-Q

39. Intramuscular

40. Intravenous (IV)

41. Quality Assurance - Injection Sites
Because of high-value meat cuts, you must be careful where to put intramuscular injections!
Injections can cause blemishes
Affects tenderness
Affects visual appeal

44. 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?
What are the 9 primal cuts of beef?
What are the top 3 quality grades?
What are the three types of injections?