1. Ruminant Anatomy and Physiology Flashcards
Four regions of the ruminant stomach
Rumen, Reticulum, Omasum, Abomasum
In the newborn calf, the large _______ is more important for milk digestion, rather than fermentation.
Abomasum
In the 5 year old cow, the rumen is large and occupies the entire ____ side of the abdomen, pushing the liver _____.
Left
Cranially
In a 6 year old heavily pregnant cow, the uterus displaces the rumen ______ and the abomasum ______.
Dorsally
Cranially
Allows the suckling calves to bypass to the abomasum
Esophageal groove
Condition in which the esophageal groove is not in place, allowing milk to enter the rumen
Rumen putrefaction
The rumen becomes functional once _____ is introduced.
Grain
Three main functional components of the rumen
Bacteria, Protozoa, Fungi
Only visible via electron microscope, they digest cellulose
Bacteria
Visible as small, medium, or large, they control the bacterial population
Protozoa
Usually present in a small amount, they aid bacteria with cellulose digestion
Fungi
Region of the ruminant stomach that acts as the hydration place, pulling out all of the water
Omasum
Region of the ruminant stomach that is the “true” stomach
Abomasum
Pressure over each area of the rumen can help determine ________ and _____ of the rumen contents
Consistency and fill
What three things can we determine from rumen auscultation?
- Rate and strength of rumen contractions
- Rumen volume
- Nature of rumen contents
With regards to reticuloruminal motility, another name for the primary cycle is _______
Mixing cycle
With regards to reticuloruminal motility, another name for the secondary cycle is _______
Eructation
What does the frequency of primary contractions indicate?
The overall health of the ruminant
How is strength of the primary cycle determined?
By observing movement and loudness of sounds
Complete absence of reticuloruminal motility
Atony
With regards to reticuloruminal motility, during atony, there is an absence of ______ inputs or an increase in ______ inputs to the gastric center of the hypothalamus
Excitatory Inhibitory
With regards to reticuloruminal motility, during atony, there is direct _______ of the gastric center
Depression
With regards to reticuloruminal motility, during atony, there is failure of the ______ or _______ pathways
Vagal (nerve lesion) or motor
Reduction in frequency OR strength of primary contraction
Hypomotility
With regards to reticuloruminal motility, during hypomotility, there is a reduction in _______ drive to the gastric center
Excitatory
With regards to reticuloruminal motility, during hypomotility, there is an increase in ______ inputs
Inhibitory
With regards to reticuloruminal motility, during hypomotility, there is weakness of the _____ pathway
Motor
The _____ cycle is necessary to prevent bloat
Secondary/Eructation
In order for the secondary cycle to occur, the ____ ____ must reach the cardia. If the cardia is in contact with foam or fluid, it will remain firmly shut.
Gas cap
Allows further breakdown of food and addition of large quantities of saliva (buffer)
Rumination
Stratification of Ingesta

- Gas cap
- Fibrous Mat
- Light liquid layer
- Dense liquid layer
What should the caudal aspect of the rumen be assessed for via internal ruminal palpation?
Volume and Consistency
5 qualities evaluated when examining feces
Amount
Color
Odor
Consistency
Degree of digestion
Decreased amount of feces could be due to which two things?
Functional obstruction
Decreased feed intake
The color of feces is influennced by composition of diet, but may also reflect what?
Mean or undigested blood
An abnormal odor to feces may indicate?
Abnormal fermentation
Fecal consistency is associated with
Hydration status and Transit time of ingest
Large fibers in feces indicates
Rapid turnover
Fine plant particles in feces indicates
Prolonged rumen turnover
Numerous corn kernels in feces indicates
Excessive grain consumption
What are the two methods for collecting rumen fluid and which is more accurate?
Ororuminal collection
Rumenocentesis (More accurate)
Why should rumen fluid samples be evaluated directly after collection?
To minimize coooling and air exposure on protozoal activity
Physical characteristics evaluated when examining ruminal fluid (4)
- Color
- Consistency
- Odor
- Sedimentation activity test
Chemical characteristics evaluated when examining ruminal fluid (5)
- pH
- Cellulose digestion test
- Glucose fermentation test
- Nitrate reduction test
- Rumen fluid chloride
Two types of microscopical exams when examining ruminal fluid
Quantitative and Qualitative
Normal rumen fluid color if eating hay
Olive to brownish green
Normal rumen fluid color if eating grain or silage ration
Yellowish brown
Abnormal rumen fluid color, black/green, indicates
Ruminal stasis
Abnormal rumen fluid color, milky gray/brown, indicates
Lactic acidosis
Normal rumen fluid consistency
Slightly viscous
Abnormal rumen fluid that appears watery indicates
Anorexia
Abnormal rumen fluid that contains excess froth indicates
Frothy bloat or vagus indigestion
An abnormally acidic rumen fluid odor indicates
Lactic acidosis
A rotting rumen fluid odor indicates
Rumen putrefaction
When performing a sedimentation activity test to evaluate microfloral activity in rumen fluid, sedimentation should occur within
4-8 minutes
On sedimentation activity test, if no sedimentation or floatation occurs, it indicates
Frothy blot or Vagus indigestion
On sedimentation activity test, if sedimentation occurs very rapidly (<3 mins), it indicates
Inactive microflora = Ruminal acidosis
Normal rumen fluid pH if grass fed
6-7
Normal rumen fluid pH if on TMR
5.5 -6
pH<5.5 indicates
Lactic acidosis
Test done on rumen fluid for anaerobic fermentation
Methylene blue reduction test
Test done for digestion of fibers
Cellulose digestion test
Test done for digestion of CHOs
Glucose fermentation test
Test done for digestion of protein
Nitrate reduction test
Normal time range for Methylene blue reduction
2-6 minutes
A methylene blue reduction test of > __ mins is inadequate and therefore ______ is indicated
>10 mins
Transfaunation
Measured in a supernatant of a centrifuged sample, a rumen fluid chloride >30 mEq/L is elevated, indicating
Abomasal Disease
Abomasal Reflux
Obstruction of intestinal flow
Percussion and Auscultation of the abomasum is done when we suspect ______ and we listen for a ______
A displaced abomasum
High pitched tympanic resonance (ping)
Abdominocentesis of a displaced abomasum
Liptak Test
Which displaced abomasum will definitely have changes seen on blood work: Left or Right?
Right Displaced Abomasum (often involves a volvulus)