Ruminant Anatomy And Physio + Ruminal disorders Flashcards
How does the anatomy of the stomach differ between newborn and adult cows?
Newborn — large abomasum for milk digestion
Adult — rumen is large and occupies entire left side; liver is pushed cranially
In calves, the ______________ groove allows milk to bypass the rumen into the abomasum
Oesophageal groove
How can we assess the bacterial population in the rumen?
Microscopically - protozoa population
When doing an external ruminal palpation, what are the normal layers you can feel?
Free gas
Fibrous mat
Fluid
What occurs during the primary mixing cycle of the rumen?
Contraction of the dorsal and ventral sacs moving contents caudally
Contraction of the caudal sacs moving material cranially
What are causes of atony in the rumen?
Absence of excitatory input or increased inhibitory input signal to hypothalamus
Direct depression of gastric center
Failure of vagal or motor pathways (lesions or hypocalcemia)
What are causes of hypomotility of the rumen?
Reduced excitatory drive to the gastric center
Increased inhibition
Weakness of motor pathways (hypocalcemia/hypokalemia)
What is the normal number of rumen contractions you should auscultation?
1-2 rumen contractions / min
What is the secondary cycle of recticuloruminal motility?
Gas layer sits dorsal in rumen. As gas expands, it extends down to cardia causing eructation
Cardia remains closed when in contact with fluid or foam
What are you looking at when examining feces?
Amount Colour Odor Consistency Degree of digestion
You take a ruminal fluid sample and it appears watery. What does this indicate?
Anorexia
You take a ruminal fluid sample and it appears very frothy. What would this indicated?
Bloat or vagus indigestion
From ruminocentesis, the fluid smells acidic. What does this indicate?
Lactic acidosis
You take a ruminal fluid sample and it smells rotten, what does this indicate?
Rumen putrefaction
What is the normal colour of rumen fluid?
Olive-brownish green — hay
Yellowish brown — grain or sialate
What is the colour of ruminal fluid in a cow with lactic acidosis ?
Milky gray/brown
Black/green coloured rumen fluid indicates?
Rumen stasis
What is the normal pH of the rumen (beef vs dairy)?
Beef (grass fed): 6-7
Dairy (TMR): 5.5 - 6
Best measured 2-4hrs after feeding concentrate or 4-8hrs after TMR
What test measures anaerobic fermentation of ruminal fluid?
Methylene blue reduction test
10ml of rumen fluid to 0.5ml of 0.03% solution
Normal clearance is 2-6mins
Abnormal >10mins
What procedure is indicated if the methylene blue reduction test is >10mins for clearance?
Transfaunation
What is normal level of rumen chloride? What does an elevated level indicate?
30mEq/L
Abomasal disease
Abomasal reflux
Obstruction of intestinal flow
What test can you do to determine microflora activity?
Glucose fermentation test
Normal microflora = 1-2ml gas/hr
Inactive flora = little or no gas production
What type of bloat is caused by esophageal or ruminal motility dysfunction?
Free gas bloat
What type of bloat is caused by high risk feeds like alfalfa or sweet clover?
Frothy bloat
Clinical signs of bloat?
Asymmetric abdominal distention, most pronounced in left paralumbar fossa
Abdominal discomfort —> kicking or rolling
Increased HR and RR
Acute: death in 30mins - 4hrs
Asymmetric abdominal distention, most pronounced in left paralumbar fossa
Abdominal discomfort —> kicking or rolling
Increased HR and RR
DDX?
Bloat Ruptured bladder Hydroallantosis LDA Abomasal volvulus Mesenteric volvulus
Treatment for free gas bloat?
Emergency : trocharization
Stomach tube
Chronic: temporary rumenotomy, find underlying pattern
Treatment for frothy bloat?
Emergency: trocharization
Polaxalene Vegetable oil Dactyl sodium sulfosuccinate Manage diet Ionophores
What causes primary (acute) rumen indigestion?
Abrupt dietary change that results in self-limited but rapid decline of rumen fermentation
What are causes of a secondary (chronic) rumen indigestion?
Result of other disease (endotoxemic infection, abomasal disease, metabolic disease)
Clinical signs of chronic rumen indigestion?
Rumination absent
Rumen under filled
Fecal production depressed
+/- diarrhea
What is the treatment for rumen indigestion?
Mild - self correcting Rumen transfaunation - from cow adapted to expected ration -min 3L, 8-16L is best - repeat for 2-3days
Increase rumen fill
- 20-30L of fluid, +/- sodium, potassium, propylene glycol, niacin, alfalfa pellets
What are causes of subacute rumen acidosis?
Not enough fiber
Component or slug feeding
Selective feeding
Subacute rumen acidosis is a risk factor for what diseases?
Rumenitis
Liver abscess
Laminitis
Posterior vena cava thrombosis
Acute death syndrome/hemorrhagic bowel syndrome (C. Perfringens)
Mycotic rumenitis
Abomasal ulceration and displacement
Cerebral-cortical necrosis - thiaminase producing bacteria
What is fat cow syndrome?
Proprionic acid surge caused by increase in lactic acid fermenters
Eg during feedlot “rounding off” phase OR dairy cows with prolonged lactation
What are your top differentials for a cow with chronic weight loss and hypoalbuminemia ?
Rumenitis
Johnes disease
Treatment for mild cases of rumentitis?
Feed antibiotics as prophylactic
Prevent further access to grain
Hay and water only
Antacid orally: MgOxide 1g/kg
How does rumenitis predispose to liver abscess?
Facilitate penetration of bacteria —> T. Pyogenes and F. Necrophorum into portal system —>liver abscess
What bacteria are associated with acute death syndrome/ hemorrhagic bowel syndrome?
C. Perfringens enterocolitis
What bacteria are associated with cerebral-cortical necrosis?
Thiaminase producing bacteria —> breakdown thiamine
C. Sporogenes
B. Thiaminolyticus
What is the cause of lactic acidosis ?
Grain overload
Increased production of lactic acid
Lactic acidosis is present when pH of the rumen is ________
<5.5
History commonly associated with lactic acidosis?
Feedlot and dairy cattle Fermentable feed (wheat, barely, corn) Usually relates to a single episode of feed intake (engorement)
What is the pathogenesis of rumen lactic acidosis?
Celluolytic and amylolytic Bacteria —> decrease pH —> proliferation of strep bovis and lactobacillus —> produce D and L lactic acid
D lactic acid cannot be metabolized
What are consequences of lactic acid accumulation?
Metabolic acidosis —> ataxia, depression, and severe nephrosis
Raises osmolarity and fluid sequestration in rumen —> dehydration, hypovolemia and circulatory collapse
Chemical rumenitits —> sloughing of mucosa and bacterial invasion
Gram negative bacteria die off —> endotoxemia (contribute to circulatory collapse)
How can a subacute/acute rumenitis be diagnosed?
Low pH
Milky-gray fluid
No protozoa
methylene blue reduction test > 5mins
Treatment for moderate to severe rumenitis?
Euthanasia /slaughter Intensive supportive care and surgery —IV fluids (polyionic fluid 10% bw) —sodium bicarb (1-3meq/kg) —NSAID —antibiotic: penicillin —Vit B1 and B12 —calcium —rumenotomy and rumen lavage (kingman tube)
How is rumenitis avoided?
Avoid sudden ration changes
Don’t slug feed
Avoid finely ground and soluble starches
Supply enough effective fiber
How can you detect feed sorting in your cattle?
Detectable in variation in manure consistency between individuals receiving the same ration.
Clincial signs of traumatic reticulopericarditis?
jugular pulse
Washing machine murmur
Abduction of the elbows
Brisket edema
How can you diagnose traumatic reticulopericardidtis?
History and PE Increased fibrinogen (acute) Increased globulin (chronic) \+/- neutrophilic Mild metabolic alkalosis Cl in rumen
Abdominocentesis
Reticulogrpahy
Ultrasound
Exploratory laparotomy
How does an abdominocentesis appear in a cow with TRP?
Increased WBC — PMN (>6000 nucleated cells/uL)
Increased protein (>3g/dL)
A dry/normal tap is inconclusive
Treatment for TRP?
Magnet PPG 5+ days NSAID Oral IV fluids Stall rest
Surgical — retrieve object/ drain perireticular abscess
What would you see on ultrasound that could indicate TRP?
Decreased reticular motility
Fibrin deposits
Perireticular abscess
What is a type I vagus indigestion?
Uncomplicated TRP —> damages vagus nerve
Failure of contractions results in free gas bloat and ruminal distention
What is a type II vagus indigestion?
Failure of omasal transport preventing aboral movement of ingesta —> functional mechanical outflow disturbance
Nerve damage can result form mycoticomastitis, reticular abscess, localized adhesions
What is type III vagus indigestion
Failure of transpyloric outflow (abomasal obstruction )
Primary obstruction — dry feed or limited water
Secondary obstruction — disturbance in motility or obstruction (vagus damage from TRP or RDA)
What is a type IV vagus indigestion?
Late gestation indigestion
During advanced pregnancy the enlarged uterus displaces abomasum which interferes with motility
Clinical signs of vagus indigestion?
Chronic progressive weight loss with abdominal distention
Papple shaped
