Exam 3: Lecture 32 - Ruminant Digestive Physiology 2

Question 1

How does the rumen look at birth?

Answer 1

-Rumen same size as abomasum
-No microbes
-Milk bypasses rumen via esophageal groove (don’t want milk in rumen)
-Thin wall w/ short papillae & undeveloped pillars

Question 2

What happens to the rumen (& calf) by 3 weeks old?

Answer 2

-Calves start to ingest forage & concentrate (grain)
-Microbes start to establish - cow licks the calf, pick up microbes from environment
-Rumen enlarges ->mucosa transforms, papillae grow

Question 3

What stimulates rumen papillae development?

Answer 3

-Grain (more than hay)
-Why grain is offered to dairy calves early

Question 4

What is the anatomical structure of the newborn/young calf that connects the cardia region to the omasum?

Answer 4

-Esophageal groove

Question 5

What is the job of the esophageal groove?

Answer 5

-Bypassing the forestomachs
-Important b/c milk is poorly digested in rumen

Question 6

When is the esophageal groove prominent in ruminants?

Answer 6

-Functional in calf through weaning age
-Inactive in adult

Question 7

Formation of the esophageal groove is stimulated by

Answer 7

-Chemical (milk)
-ADH
-Suckling

Question 8

Rumen fermentation produces a lot of gas, what are they?

Answer 8

-65% CO2
-25% CH4
-7% N
-Trace amounts of O2, H2, and H2S

Question 9

How much gas does rumen fermentation produce?

Answer 9

-Up to 600 L of gases/day

Question 10

What is eructation stimulated by?

Answer 10

-Gas pressure in the rumen

Question 11

What are the major gases that stimulates eructation?

Answer 11

-CO2 & CH4
(Gas production peaks 30 min. to 2 hours after feeding)

Question 12

What forces gas into the reticulum towards the cardia during eructation?

Answer 12

-Secondary rumen contractions

Question 13

What are the 5 F’s of abdominal distension?

Answer 13

-Fart (gas)
-Fluid
-Food
-Fetus
-Fat (visceral/intra-abdominal fat, subcutaneous/extra-abdominal fat)

Question 14

What is important when you have a “bloated animal”?

Answer 14

-Important to ascertain cause of abdominal distention when examining a “bloated” animal

Question 15

What is “vagal indigestion syndrome”?

Answer 15

-Gradual development of abdominal distention secondary to rumenoreticular distention

Question 16

What causes vagal indigestion syndrome?

Answer 16

-Diseases resulting in injury, inflammation, or pressure on vagus nerve

Question 17

How many “types” of vagal indigestion syndrome are there?

Answer 17

-4

Question 18

What is type 1 vagal indigestion syndrome?

Answer 18

-Free gas bloat/failure to eructate

Question 19

What is type 2 vagal indigestion syndrome?

Answer 19

-Failure of transport out of rumen (blockage at reticulo-omasal orifice)

Question 20

What is type 3 vagal indigestion syndrome?

Answer 20

-Failure of transport out of abomasum (blockage - impaction or displacement)

Question 21

What is type 4 vagal indigestion syndrome?

Answer 21

-Indigestion associated with advanced pregnancy (large fetus shifts the location of the abomasum)

Question 22

What is this shape called?

Answer 22

-Papple shape

Question 23

Explain a “papple shaped abdomen

Answer 23

-Lower & upper left quadrants are both bloated (apple shape)
-Lower right is bloated (pear-shaped)

Question 24

What is bloat (ruminal tympany)?

Answer 24

-Overdistention of the rumenoreticulum with gases of fermentation

Question 25

What types of bloat (ruminal tympany) are there?

Answer 25

-**Frothy bloat** (primary ruminal tympany) -**Free gas bloat** (secondary riminal tympany)

Question 26

What is **frothy bloat** (primary ruminal tympany)?

Answer 26

-Gas dissolved in liquid digesta (causes foam)

Question 27

What is **free gas bloat** (secondary ruminal tympany)?

Answer 27

-Gas separated from digesta

Question 28

What causes **free gas bloat** (secondary ruminal tympany)?

Answer 28

-Esophageal obstruction (choke) -Interference in nerve pathways involved in eructation -Grain overload leading to esophagitis & rumenitis interfering with eructation

Question 29

How do we "fix" **free gas bloat** (secondary ruminal tympany)

Answer 29

-Stomach tube to relieve gas pockets -Trocar (through skin into rumen) -Rumenotomy (surgical incision into rumen to relieve gas)

Question 30

Explain **frothy bloat** (primary ruminal tympany)

Answer 30

-Foam mixed w/ ruminal contents -Stable foam of small gas bubbles & eructation can't occur (b/c can only eructate free gas) -Froth gets up against cardia region & any free gas there also can't be eructated -High surface tension

Question 31

What causes **frothy bloat** (primary ruminal tympany)?

Answer 31

High legume diets -Soluble proteins & saponins allow small bubbles to form Feedlot cattle -Fine particle size of diet allows gas bubbles to form

Question 32

How can we prevent & treat **frothy bloat**?

Answer 32

-Limit time on high-risk pastures (ex: legume pastures), give anti-foaming agents -Mineral oil can treat b/c it is a surfactant & will break up the foam

Question 33

What is traumatic reticuloperitonitis?

Answer 33

-Hardware disease -Heavy material/foreign objects fall into the reticulum during primary rumen contractions -> reticulum contractions force sharp objects to penetrate wall -> also prevents movement of rumen contents through reticulo-omasal orifice

Question 34

What are the resulting problems of traumatic reticuloperitonitis depending on direction of penetration?

Answer 34

-Liver abscess -Pleuritis -Pericarditis -All accompanied by peritonitis

Question 35

What are the clinical signs of hardware disease?

Answer 35

-Rumen motility slows down/stops -Reduced appetite, milk production decreases in dairy cows -Fever -Abdominal pain -Arched back -Reluctant to move -Abducted elbows -Grunt on expiration

Question 36

How is hardware disease diagnosed?

Answer 36

-Withers pinch test: grunt or hold breath -Abdominal paracentesis -Hemogram (complete blood count) -Imaging

Question 37

How is hardware disease treated?

Answer 37

Medical -Administer a magnet -Antibiotics Surgical -Rumenotomy

Question 38

How is hardware disease prevented?

Answer 38

-Clean up the environment (baling & fence wire) -Magnets in feed handling equipment -Prophylactic magnets to all adult cattle

Question 39

What is meant by "displaced abomasum"?

Answer 39

-Abomasum suspended loosely by greater & lesser omentum in right front quadrant of abdomen

Question 40

Explain a LDA

Answer 40

-Hypomotility & gas production that causes displacement towards the left laterally towards the lumen

Question 41

Explain a RDA

Answer 41

-Hypomotility & gas production that causes a counterclockwise rotation (when viewed from back) -Leads to obstruction & ischemia

Question 42

What factors can contribute to a displaced abomasum?

Answer 42

Hypomotility -High grain diet = less motility, get more gas flowing into the abomasum Periparturient changes in location of intra-abdominal organs -Happens within ~14 days of calving

Question 43

What determines the rumen pH?

Answer 43

-Intake of fermentable carbohydrates -Buffering capacity of rumen -Rate of VFA absorption

Question 44

What happens during rumen acidosis?

Answer 44

-Abrupt increase in readily fermentable carbohydrates -Rumen microflora need time to transition from cellulolytic -> amylolytic, so sudden diet change upsets rumen

Question 45

What are the types of rumen acidosis?

Answer 45

-Subacute rumen acidosis (SARA) -Acute rumen acidosis

Question 46

What is subacute rumen acidosis (SARA)?

Answer 46

-pH drop not as severe & due to overall accumulation of VFAs -Lactic acid production starts and will accumulate

Question 47

What are the steps to development of SARA?

Answer 47

-Shortage of amylolytic bacteria allows S. bovis to grow & produce lactic acid -Lactic acid builds up, pH drops

Question 48

What are the clinical signs of SARA?

Answer 48

-Clinical signs not as severe, but feed intake decreases & milk production stops

Question 49

This is showing signs of

Answer 49

-Rumen acidosis

Question 50

What is acute acidosis?

Answer 50

-pH < 5.5 -Lactic acid accumulation, pH depression extreme, some lactic acid absorption into blood -pH in rumen can drop as low as 4.0 causing papillae to peel (parakeratosis) - bacteria invade rumen wall

Question 51

What is the treatment/prevention for SARA & acidosis?

Answer 51

-Feed ionophores, buffers, lactic acid utilizing bacteria

Question 52

What is the primary gas produced by fermentation in the rumen?

Answer 52

-CO2 (2nd is methane)

Question 53

Which type of bloat is associated with an obstruction interfering with eructation of gas?

Answer 53

-Free gas bloat (obstruction like choke)