Welcome Class!

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.

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 other animals are ruminants?

What is this?

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

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

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

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

Marbling

Prime

Choice

Select

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

Sub-Q

Intramuscular

Intravenous (IV)

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

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?