L1 - GI Rumen Anatomy & Physiology Flashcards
What are the 4 regions of the ruminant stomach?
- Rumen
- Reticulum
- Omasum
- Abomasum
Describe the different GI characteristics in a newborn calf.
Large abomasum more important for milk digestion rather than fermentation
What differences do you see in GI of the 5-year-old cow?
The rumen is large and occupies the entire left side of the abdomen.
The liver is pushed cranially.
What changes in GI do you see in a 6 y/o heavily pregnant cow?
The uterus displaces the rumen dorsally and the abomasum cranially.
TRUE/FALSE:
the Esophageal groove allows suckling calves to bypass to the omasum.
FALSE
It bypasses to the ABOMASUM
When does the rumen become functional?
Once grain is introduced
What types of organisms are found within the rumen?
- Bacteria (largest)
- Protozoa
- Fungi (smallest population)
What is the function of bacteria within the rumen?
Digest cellulose
What is the function of protozoa within the rumen?
- Control the bacterial population
- You want to ensure that there is a diverse bacterial population (small, medium, large)
What is the function of fungi within the rumen?
Aid bacteria with cellulose digestion
TRUE/FALSE
The omasum lies on the medial aspect of the rumen and is responsible for absorption of water.
TRUE
What part of the GI secretes enzymes & HCl for digestion?
Abomasum
TRUE/FALSE
Disruptions with the abomasum may lead to metabolic changes.
TRUE
TRUE/FALSE
Dairy cattle fed with TMR and grass fed beef cattle have the same rumen composition.
FALSE
What when visually assessing your cattle, where should you start?
From the back.
Look at symmetry
What is the point of doing an external ruminal palpation?
Put pressure on each area in order to determine consistency and fill. You may be able to palpate distinct layers
What are the different rumen layers?
Top: Gas Cap
Middle: Fibrous Mat
Bottom: Liquid
What are you listening for on rumen auscultation?
Rate and strength of rumen contractions
_____ is associated with cud chewing.
Rumination
_____ is associated with suckling milk.
Esophageal groove closure
What are the different parts of the reticuloruminal motility cycle?
Primary or mixing cycle
Secondary or eructation cycle
What is atony?
Complete absence of reticuloruminal motility
What are the causes of atony?
- Absence of excitatory inputs or increase in inhibitory inputs to the gastric centre of the hypothalamus
- Direct depression of the gastric centre
- Failure of the vagal (nerve lesion) or motor pathways (Hypocalcemia)
What pathologies may be seen with the primary/mixing cycle?
- Atony
- Hypomotility
TRUE/FALSE
Frequency of 2˚ contractions indicates the overall health of the ruminant.
FALSE
1˚
____ is determined by observing movements and loudness of sound (Primary/mixing cycle)
Strength
TRUE/FALSE
The 1˚ and 2˚ cycles are easily differentiated on auscultation.
FALSE
What will cause the cardia to remain firmly shut during the 2˚/eructation cycle?
The cardia will remain firmly shut if foam or fluid is in contact.
______ allows for further breakdown of food and addition of large quantities of saliva.
Bonus: What is the role of saliva during this process?
Rumination
Bonus: acts a buffer
What is assessed during an internal luminal palpation?
The caudal aspect of the rumen is assessed for volume and consistency.
What qualities of feces are examined?
- Amount
- Color
- Odor
- Consistency
- Degree of Digestion
What may cause ↓ amount of feces?
Functional obstruction or ↓ intake
Color of feces is influenced by _____.
composition of diet
*may also reflect mean or undigested blood
What does a strange odor of feces indicate?
Abnormal fermentation
What is consistency of feces associated with?
Hydration status and transit time of ingesta
When examining feces, what is indicated by each of the following:
- Large fibers
- Fine plant particles
- Numerous corn kernels
- rapid turnover
- Prolonged rumen turnover
- Excessive Grain consumption
What are collection methods of rumen fluids?
- Ororuminal
2. Rumenocentesis (preferred)
What are some precautions for rumen fluid examination?
- Samples should be evaluated directly after collection to minimize cooling and exposure on protozoal activity.
- Transport of luminal fluid for long distance must be done in double jacket container (No light and keeps cool).
- Estimation of chloride and ammonia concentrations can be delayed up to 9 hrs in room temp and up to 24 hrs in refrigerator.
What physical characteristics of ruminal fluid are examined?
- Color
- Consistency
- Odor
- Sedimentation activity test
What chemical characteristics of ruminal fluid are examined?
- pH
- Cellulose digestion test
- Glucose fermentation test
- Nitrate reduction test
- Rumen fluid chloride
What kind of microscope exams are done on ruminal fluid?
Quantitative
Qualitative
What is the normal color of rumen fluid?
- Depends on feed
- Olive-brownish green (hay)
- Yellowish brown color (grain/silage)
Upon examination of rumen fluid, it is black/green. What is your top differential?
Ruminal Stasis
Upon examination of rumen fluid, it is milky gray/brown. What is your top differential?
Lactic Acidosis
What is the normal consistency of rumen fluid?
Slightly viscous
Upon examination of rumen fluid, its consistency is like a water sample. What is your top differential?
Anorexia/rumen acidosis
Upon examination of rumen fluid, it has excess froth. What is your top differential?
Frothy bloat
Vagus indigestion
What is the normal odor of rumen fluid?
Aromatic?
Upon examination of rumen fluid, it has an acidic odor. What is your top differential?
Lactic acidosis
Upon examination of rumen fluid, it has a rotting odor. What is your top differential?
Rumen putrefaction
What are the characteristics of rumen fluid of a cow with lactic acidosis?
- Acidic Odor
- Milky gray/brown color
What does the sedimentation activity test evaluate in rumen fluid?
Microfloral Activity
You perform a sedimentation activity test on rumen fluid. Interpret the possible results:
- No sedimentation or floatation
- Very rapid sedimentation <3min
- Frothy bloat, vagus indigestion
2. Inactive micro flora (ruminal acidosis)
When is the best time to measure pH of rumen fluid?
2-4 hrs after feeding concentrate or 4-8 hrs after offering TMR
What is the expected pH for the following feed types?
- Grass
- TMR
- Grass: 6-7 (more alkaline)
- TMR/Grain: 5.5-6
You analyze rumen fluid with a pH <5.5. What is this indicative of?
pH <5.5 indicates lactic acidosis
Match the test with chemical characteristic
- Anaerobic Fermentation
- Digestion of fibers
- Digestion of Carbohydrates
- Digestion of Protein
a. Glucose fermentation test
b. Methylene blue reduction test
c. Nitrate Reduction Test
d. Cellulose digestion test
- b
- d
- a
- c
What is the normal level for rumen fluid chloride?
30 mEq/L
What are your differentials for elevated Rumen Fluid chloride?
- Abomasal Disease
- Abomasal reflux
- Obstruction of intestinal flow
*think abomasal problem since abomasum releases chloride
What is being analyzed during a qualitative analysis of rumen fluid?
Motility of Protozoa >40x/field
What is examined during a quantitative analysis of rumen fluid?
protozoal count/ml
TRUE/FALSE
Diagnosis of omasum disorders is difficult and typically through a rule to dx.
TRUE
What are some examinations that can be done during clinical assessment of the abomasum?
- Percussion & Auscultation
- Abdominocentesis
- Blood work (metabolic changes can occur)
*think of where it is, how big it is, what kind of gas is there