Lecture 21 3/25/25

Question 2

What is the normal rate of rumen contractions?

Answer 2

2 contractions a minute to 3 contractions every 2 minutes

Question 3

What are the typical layers found within the rumen/

Answer 3

-gas at the top
-fiber mat in the middle
-fluid phase at the bottom

Question 4

What is the purpose of primary rumen contractions?

Answer 4

move material from the rumen to the reticulum

Question 5

What is the purpose of secondary rumen contractions?

Answer 5

eructation of gas out of the rumen

Question 6

What are the main volatile fatty acids?

Answer 6

-acetate
-propionate
-butyrate

Question 7

Which molecules are fermented by bacteria in the rumen?

Answer 7

-glucose
-fat
-microbial proteins
-essential vitamins

Question 8

What is the role of acetate?

Answer 8

building block for fatty acids such as butter fat and triglycerides

Question 9

What is the role of propionate?

Answer 9

glucose precursor that provides resources for the Kreb’s cycle

Question 10

What is the role of butyrate?

Answer 10

less commonly utilized, more inert byproduct of fermentation

Question 11

What causes each of the abdominal contours in the depiction?

Answer 11

A: rumen tympany/free gas bloat
B: frothy bloat
C: vagus indigestion
D: right-sided distention due to cecal volvulus or RTA
E: abomasal impaction

Question 12

How can rumen fluid be collected?

Answer 12

-OG tube: will be contaminated with saliva
-rumenocentesis: requires percutaneous aspiration

Question 13

What is the pH of normal rumen fluid, acidotic rumen fluid, and saliva?

Answer 13

-normal rumen: 5.5 to 7 pH
-acidotic rumen: < 5.5 pH
-saliva: 8 pH

Question 14

What is the typical cause of high rumen fluid pH?

Answer 14

salivary contamination

Question 15

What is the normal odor of rumen fluid?

Answer 15

aromatic and unobjectionable

Question 16

What is the qualitative examination of rumen fluid?

Answer 16

-observation of big, medium, and small protozoan activity
-want a good amount of activity from all three sizes
-larger protozoa will die off first when problems occur

Question 17

Which metabolic function test can be done on rumen fluid?

Answer 17

new methylene blue reduction

Question 18

What are the characteristics of simple indigestion?

Answer 18

-mild disruption of normal rumen fermentation
-occurs with sudden diet changes, stress, and spoiled feed

Question 19

What are the clinical signs of simple indigestion?

Answer 19

-mild bloat
-diarrhea 12 to 24 hours later
-decreased milk production
-weak rumen contractions

Question 20

What are the treatment steps for simple indigestion?

Answer 20

-typically self-resolves
-free choice bicarbonate
-transfaunation
-good quality hay
-possibly probiotics

Question 21

What are the characteristics of ruminal acidosis?

Answer 21

-dramatic disruption of rumen fermentation
-abrupt change in the non-structural carbohydrates
-exacerbated by external stressors

Question 22

How does the level of feed processing impact digestibility and bloat?

Answer 22

feeds that are more highly processed and/or have more moisture are more digestible/fermentable; more gas is produced which increases chances for bloat

Question 23

What are the steps of rumen acidosis pathogenesis?

Answer 23

1. excessive grain/starch intake
2. non-structural carbs are converted to glucose
3. glucose is used to produce VFAs and D- and L-lactic acid
4. D- and L-lactic acid destroy good microflora and epithelium, reduce motility, and are systemically absorbed
5. destroyed microflora release endotoxins
6. Fusobacterium necrophorum, Trueperella pyogenes, and Strep. bovis cause rumenitis and enter circulation
7. lactic acid production and abnormal fermentation dramatically increases rumen fluid osmolality; water rushes into rumen and causes distention

Question 24

How does L-lactic acid differ from D-lactic acid?

Answer 24

-L-lactic acid results from anaerobic metabolism and is normal
-D-lactic acid is produced by bacterial fermentation and cannot be used by mammals

Question 25

What are the clinical signs of acute ruminal acidosis?

Answer 25

-toxemia -bloat -dehydration -ataxia -recumbency -metabolic acidosis -fetid diarrhea -possible death

Question 26

What are the clinical signs of subacute ruminal acidosis/SARA?

Answer 26

-signs similar to recurring simple indigestion -incidence increased with stress

Question 27

What are the clinical signs of chronic ruminal acidosis?

Answer 27

-months of ups and downs in fermentation -thickening and cornification of rumen wall -blunting of papillae -poor production -unthrifty

Question 28

Why is acute ruminal acidosis life threatening?

Answer 28

-abdominal pressure can impact CV system -acidemia can cause death

Question 29

How is ruminal acidosis diagnosed?

Answer 29

*clinical presentation and history *rumen fluid analysis -pH < 4.5 (acute) -pH 4.5 to 5.5 (SARA) -few to no protozoa -foul smelling, gray/yellow fluid

Question 30

What are the treatment steps for ruminal acidosis?

Answer 30

*restore the rumen -empty rumen contents -raise rumen pH -activated charcoal (true toxins) -transfaunation *rehydrate -oral and IV fluids *systemic therapy -antibiotics -NSAIDs

Question 31

What are the long term sequelae of ruminal acidosis?

Answer 31

-laminitis -liver abscess -caval syndrome -parakeratosis -mycotic rumenitis -polioencephalomalacia -low butter fat -poor production

Question 32

How is ruminal acidosis prevented?

Answer 32

-avoid rapid changes in diet -avoid feed bunk drama -maintain adequate amounts of forage

Question 33

What are the characteristics of rumenitis?

Answer 33

-inflammation of rumen wall following toxic/caustic insult -almost always associated with ruminal acidosis -damage to wall of rumen leads to shed of bacteria into circulatory system -can cause liver abscess, septic renal infarcts, and vegetative endocarditis

Question 34

Which pathogens are associated with rumenitis?

Answer 34

-Fusobacterium necrophorum (esp. liver abscess) -Strep. bovis -Trueperella pyogenes (seen in all abscesses)

Question 35

Where do bacteria spread to following rumenitis?

Answer 35

-liver -right side of heart -lungs

Question 36

What are the characteristics of vagal indigestion?

Answer 36

-syndrome of motor neuron dysfunction of the forestomachs -NOT a diagnosis -many possible etiologies; hardware disease is most common

Question 37

What are the four types of vagal indigestion?

Answer 37

type 1: failure to eructate type 2: failure of omasal transport type 3: failure of abomasal transport type 4: pregnancy associated

Question 38

What can cause type 1 vagal indigestion?

Answer 38

-foreign body -pneumonia -calf diphtheria

Question 39

What can cause type 2 vagal indigestion?

Answer 39

-impaction -traumatic reticuloperitonitis/hardware dz -foreign body

Question 40

What can cause type 3 vagal indigestion?

Answer 40

-displaced abomasum -lymphosarcoma -ulceration -impaction -volvulus of duodenal flexure

Question 41

What can cause type 4 vagal indigestion?

Answer 41

-late gestation -diffuse peritonitis

Question 42

What are the clinical signs of vagal indigestion?

Answer 42

-gradual distention of rumen -"papple" contour -homogenization of rumen contents -anorexia -bradycardia -scant mucoid feces -hypermotile/hypomotile rumen contractions

Question 43

What causes the following abdominal contours?

Answer 43

A: normal contour E: vagal indigestion type 2; omasal transport failure F: vagal indigestion type 3; pyloric outflow obstruction M: vagal indigestion type 3; abomasal impaction

Question 44

What is the appearance of type 1 vagal indigestion?

Answer 44

very massive cow; too large to see any papple contour