Unit 3A: The Ruminant Digestive System

Question 1

A function of the ruminant digestive system is to be able to get energy from _____

Answer 1

fibrous plants, better than other herbivores

Question 2

As sheep and cattle get older, which parts of the stomach components change and in which way?

Answer 2

With increased age, the size of the reticulorumen increases and the size of the abomasum decreases

Question 3

How many compartments make up the stomach in ruminants and what are they?

Answer 3

4 Parts:

1. rumen
2. reticulum
3. omasum
4. abomasum

Question 4

What is unique about the esophagus in ruminants?

Answer 4

-bi-directional which allows for cud to be regurgitated

Question 5

What is cud and why is it regurgitated?

Answer 5

• partially digested food

- regurgitations allows for more chewing and mixing with saliva

Question 6

What is the basic pathway of cud?

Answer 6

• after swallowed again gets passed to reticulum

- slowly moves to reticulum for fermentation ~48hrs

Question 7

Briefly describe the structure and function of the rumen component in the ruminant stomach

Answer 7

Structure: 75% of abdomen, 182 L, contains papillae, pH ~6.5-6.8
Function: nutrient absorption, starch and sugar digestions, produces gas

Question 8

Briefly describe the structure and function of the reticulum/reticulorumen

Answer 8

Structure: micro-organisms present, 23L, small muscular folds, honeycomb appearance
Function: fermentation/breakdown of plant cell walls, volatile fatty acids produces as byproduct that are used for fat/glucose synthesis and later used for energy, also traps swallowed objects

Question 9

Briefly describe the omasum

Answer 9

• spherical shaped
• connected to reticulum
• absorbs nutrients and water

Question 10

Briefly describe the structure and function of the abomasum

Answer 10

Structure: true stomach, chief cells, highly acidic pH
Function: produces HCl, pepsin, receives lipase, chief cells secrete mucous which protect from acidic pH

Question 11

Why is it important for the small intestine to have a more neutral pH?

Answer 11

• protects tissues

- enzymes (proteins) denature at lower pH

Question 12

What are the different types of ruminant feeders?

Answer 12

1. Concentrate selectors
2. Grass/roughage eaters
3. Intermediate

Question 13

Briefly explain what concentrate selectors are

Answer 13

• selective browsing and eat specific plant parts
• limited ability to digest plant fibre
• small reticulorumen relative to body size
  e. g. deer, giraffes