Exam 3 - Forestomach Disorders

Question 1

how is rumen health assessed by rumen fluid analysis?

Answer 1

protozoal numbers & activity

new methylene blue reduction

sedimentation examination

Question 2

what is the new methylene blue reduction test? what is an abnormal result?

Answer 2

qualitative measure of the redox potential of rumen fluid generated by microbial fermentation to check for the function of anaerobic bacteria

abnormal - > 8-10 minutes, indicates microbial inactivity/death

Question 3

what is a sedimentation rate used for rumen fluid analysis? what is an abnormal result?

Answer 3

qualitative estimate of microbial activity & dietary particle size

floatation is minimal or not observed with inactive/decreased particle-associated bacteria - can indicate frothy bloat

Question 4

what is simple indigestion/rumen dysbiosis?

Answer 4

transient inappetence due to changes in rumenal microenvironment

Question 5

what are some general causes of simple indigestion/rumen dysbiosis?

Answer 5

moldy/spoiled feed, indigestible roughage, too much feed, & new type/batch of feed

Question 6

how is simple indigestion/rumen dysbiosis diagnosed?

Answer 6

rule out - usually multiple animals are affected

Question 7

what are the clinical signs associated with rumen dysbiosis/simple indigestion?

Answer 7

decreased appetite, decreased milk production, rumen hypomotility, mild bloat, & abnormal feces

Question 8

how is simple indigestion/rumen dysbiosis treated?

Answer 8

usually resolves spontaneously once the feeding error has been corrected

Question 9

what causes rumen acidosis?

Answer 9

overindulgence on carbs

readily digestible carbohydrates (such as starch. sugar, or pectin) are rapidly fermented an unadapted rumen resulting in increased VFA & lactate concentrations & a reduction in rumen pH

Question 10

what are some common offenders that cause rumen acidosis?

Answer 10

cereal grains - corn, wheat, barley

high sugar/starch fruit or root crops

corn or milo stubble fields

byproduct feeds - bakery waste & brewer’s grain

Question 11

what is the pathogenesis of rumen acidosis?

Answer 11

1. within 2-6 hours after ingestion, rumenal bacterial population begins to shift towards increased numbers of gram positive bacteria
2. fermentation is altered with a shift in VFA production from acetic > propionic > butyric to propionic > acetic > butyric and increased concentrations of undissociated VFAs lactate & glucose
3. rumen protozoa decline & lactate begins to accumulate at pH of 5.5 - dying protozoa release amylase & contribute to increased glucose generation from starch
4. these conditions favor proliferation of strep bovis & other gram positives that produce lactate & once pH falls to 5.0, gram negative organisms decline rapidly & there is a local release of endotoxin
5. pH 4.5, lactobacillus spp. predominate with rapid production of lactate & histamine
6. ability of the rumen to buffer acid is overwhelmed at pH <5, and D- & L- lactate accumulate causing a systemic lactic acidosis & metabolic acidosis
7. rumen epithelium is damaged as a result of acids & other mediators released during acute acidosis

Question 12

what bacteria predominate during rumen acidosis?

Answer 12

step. bovis & lactobacillus

Question 13

what is going on with d-lactate & l-lactate during rumen acidosis?

Answer 13

l-lactate is metabolized but d-lactate isn’t & it builds up causing a metabolic acidosis

Question 14

what damage occurs to the rumen epithelium in rumen acidosis?

Answer 14

chemical rumenitis, epithelial necrosis, absorption of bacteria into portal blood, & bacterial & fungal rumenitis

Question 15

T/F: acute rumen acidosis is an individual animal disease while subacute rumen acidosis is a herd disease

Answer 15

true

Question 16

what are some clinical signs associated with acute rumen acidosis?

Answer 16

individual animal disease!!!! sick!!!!

anorexia, depression, splashy/distended/static rumen, dehydration, tachycardia, cold extremities, weak or recumbent, diarrhea with or without grain, & death

Question 17

what factors can influence the development of acute rumen acidosis?

Answer 17

rate of dietary adaption, type of carb & processing method, forage availability, feed sorting, feeding frequency, feed intake, & feed mixing/delivery

Question 18

why are clinical signs of subacute rumen acidosis not as severe as acute?

Answer 18

the changes in fermentation rate, pattern, & rumen pH are temporary & not as severe

Question 19

what is supportive of acute rumen acidosis on rumen fluid analysis?

Answer 19

foul smell, pH <5.5, & dead protozoa & gram positive bacteria

Question 20

what may be seen on lab tests in an animal with acute rumen acidosis?

Answer 20

metabolic acidosis, increased anion gap, hemoconcentration, pre-renal azotemia, & mild-to-moderate hypocalcemia

Question 21

what are some clinical signs associated with subacute rumen acidosis?

Answer 21

herd disease!!!

decreased/variable feed intake, decreased performance/increased culling, increased incidence of lameness, milk component changes (decreased milk fat % & inversion of fat:protein ratio), & loose feces

Question 22

T/F: history & physical exam findings will not be pathognomic for subacute rumen acidosis

Answer 22

true

Question 23

how can subacute rumen acidosis be diagnosed?

Answer 23

ration analysis, rumenocentesis (pH >5.8, normal), manure scoring, lameness scoring, & milk fat inversion

Question 24

why does sudden introduction of fermentable carbs or a sudden change in amount of fermentable carbs carry a higher risk of developing acute rumen acidosis?

Answer 24

dietary adaption is necessary to build up populations of lactate-using bacteria, and you need to maintain the equilibrium between acid production & acid utilization

Question 25

what is the classic example of acute rumen acidosis?

Answer 25

animals accidentally gain access to a grain storage area & engorge themselves

Question 26

why does processing method carry risk for an animal developing rumen acidosis?

Answer 26

small particle size (fine grinding), heat or pressure processing, & high moisture storage of grain increase starch availability

Question 27

list the types of carbs that carry the highest risk of rumen acidosis

Answer 27

wheat = barley > corn > sorghum = oats

Question 28

how can feeding smaller meals frequently help prevent rumen acidosis?

Answer 28

not as much grain in the food when compared to 1 large meal

Question 29

what are some examples of causes for fluctuations in feed intake?

Answer 29

inclement weather, disease, management changes

Question 30

what animals may show predisposition to developing acute rumen acidosis?

Answer 30

feedlot animals/dairy cattle in transition from the dry to lactating period dairy cattle in early lactation animals being fitted for show or sale

Question 31

T/F: acute rumen acidosis is one of the rare conditions that results in metabolic acidosis in adult ruminants

Answer 31

true

Question 32

what are the principles for treating rumen acidosis?

Answer 32

remove further access to carbs - evacuate rumen contents (surgical or rumen lavage), correct dehydration & systemic acidosis, neutralize rumen pH stop acidification, correct metabolic abnormalities, reestablish flora, prevent sequelae, surgical/medical intervention

Question 33

what are some possible sequelae of rumen acidosis?

Answer 33

bacterial rumenitis, bacteremia/septicemia, fungal rumenitis, liver abscesses, metastatic pneumonia, polioencephalomalacia, & laminitis

Question 34

how is rumen acidosis prevented?

Answer 34

prevent accidents, transition cattle slowly to high concentrate diets, use ionophores, & buffers

Question 35

how is subacute rumen acidosis treated?

Answer 35

managed by dietary changes rather than treatment of individual animals

Question 36

what is bloat?

Answer 36

occurs when eructation is impaired & the rumen becomes overdistended with froth or gas

Question 37

what is primary ruminal tympany?

Answer 37

dietary factors lead to frothy or foamy rumen contents - gas bubbles are trapped by the froth/foam & eructation of gas is prevented

Question 38

what is secondary ruminal tympany?

Answer 38

following physical obstruction of the cardia or impairment of the rumenoreticular function with accumulation of free gas in the rumen

Question 39

what is the similar appearance & clinical signs shared between animals with primary & secondary ruminal tympany?

Answer 39

distended rumen & left paralumbar fossa dyspnea, abdominal pain, staggering, & death

Question 40

how does a stomach tube help differentiate between primary & secondary ruminal tympany?

Answer 40

primary - stomach tube passes easily but does not relieve bloat, frothy contents may be seen at the end of the tube secondary - stomach tube passes & relieves bloat or the stomach tube will not pass

Question 41

primary ruminal tympany affects what animals?

Answer 41

ruminants on pasture - pasture bloat ruminants fed high concentrate diets - feed lot bloat

Question 42

when can frothy bloat affect feedlot cattle?

Answer 42

those fed high protein pelleted rations early in the feeding period

Question 43

what is the pathogenesis of pasture bloat?

Answer 43

foaming agents (soluble proteins) are contained in the plant - lush, rapidly growing legumes (alfalfa, clover, winter wheat) that contain large amounts of proteins that are rapidly degradable & produce gas at a rapid rate - gas is trapped in the froth/foam

Question 44

what is the pathogenesis of feedlot bloat?

Answer 44

high grain diets slow rumen motility & decrease saliva production ingestion of high grain, low roughage (> 50% grain) diets results in mucopolysaccharide (slime) production by bacteria within the rumen which increases the viscosity of rumen fluid resulting in trapped gas & formation of stable foam

Question 45

why do finely ground diets increase the risk of feedlot bloat?

Answer 45

they increase the fermentation rate & decrease salivation

Question 46

when is feedlot bloat most likely to occur?

Answer 46

transition to a high grain diet is rapid or when very high concentrate diets are fed for a long time late in the finishing period

Question 47

what are some clinical signs of primary ruminal tympany?

Answer 47

severe abdominal distension, gasping for breath, prolapsed rectum, raised tailhead, & dead

Question 48

what is the preferred treatment for pasture bloat?

Answer 48

poloxalene - ionic surfactant that lowers the surface tension of foam

Question 49

what is the preferred treatment for feedlot bloat?

Answer 49

intraruminal administration of mineral oil to destabilize froth

Question 50

with both pasture bloat & feedlot bloat, why tie a rag in the animals mouth?

Answer 50

helps increase saliva production & stimulates chewing which increase rumenoreticular motility

Question 51

how is primary rumen tympany prevented?

Answer 51

antifoaming agents, grazing control - rotational or strip grazing, limit overgrazing, graze mature pasture, mixed pastures, feed prior to turnout feed ionophores

Question 52

what is secondary rumen tympany?

Answer 52

occurs when gas production continues but eructation of gas is limited - failure of eructation

Question 53

what are some examples of causes of secondary rumen tympany?

Answer 53

esophageal blockage & during step up to a high concentration diet

Question 54

how is secondary rumen tympany diagnosed?

Answer 54

pass a tube - try to release gas & treat the underlying cause

Question 55

how is secondary rumen tympany treated?

Answer 55

cause dependent - if you can't pass a tube, can do an indwelling rumen trochar or temporary rumenostomy

Question 56

when is rumen fluid analysis indicated?

Answer 56

off-feed animal rumen atony abdominal or rumen distension of undetermined origin history consistent with indigestion, acidosis, or urea toxicosis assist in diagnosis of feed quality or feed mixing/delivery problems