Lab 8: Ruminal Fluid Flashcards
How to obtain ruminal fluid?
- by orogastric tube
- by ruminal puncture
what tubes are not allowed in a orogastric sample taking?
ones with internal diameters of less than 1.5cm
- they may become obstructed with ingesta
How do we confirm that the tube is in the rumen?
Using auscultation of the abdomen as ait is simultaneously blown into the tube.
Why should the initial fluid portion be discarded?
it often contains an excessive amount of saliva
- this elevates pH level in saliva
Where is a ruminal puncture sample taken?
The site is marked by the horizontal line level with the top of the patella about 15 to 20 cm posterior to the last rib.
How must ruminal fluid be transported for long distance?
in double jacket container.
What is the latest was can estimate the ammonia or chloride conc?
can be delayed up to 9 hrs in room temperature and up to 24 hrs in refrigerator
What influences the ruminal fluid composition?
composition of the diet, the circumstances of the feeding and sampling, and the time interval from feeding or drinking
When should samples be taken?
at least 4-6 hours from the feeding, and the animals should not drink before the sampling.
- food will increase fermentation
- water will dilute the sample, decrease temp
What do we physically examine in ruminal fluid?
- odour
- colour
- consistency
- sedimentation time or sedimentation/floatation test
Physical Examination:
Odour
Normal vs abnormal
Normal:
-Aromatic odour
Abnormal:
- Ammonia smell (urea poisoning)
- Mouldy rotting (protein putrefaction)
- Acidic or sour odour (excess lactic acid/grain overfeeding)
Physical Examination:
Colour
Normal:
Olive to brownish green (hay ration)
Deeper green color (green ration)
Yellowish brown color (grain or silage ration)
Abnormal:
Milky grey (grain overfeeding, lactic acidosis)
Darker greenish or brownish (ruminal stasis/decomposition)
Grey with clots of milk (calves with abomasal reflux)
Physical Examination:
Colour
- Milky gray
grain over feeding, lactic acidosis
Physical Examination:
Colour
darker greenish or brownish
ruminal stasis/decomposition
Physical Examination:
Colour:
Grey with clots of milk
Calves with abomasal reflex
Physical Examination:
Consistency
Normal?
slightly vicous
Physical Examination:
Consistency:
Increased viscosity?
saliva contamination
Physical Examination:
Consistency:
Decreased viscosity, watery with few feed particles
inactive bacteria or protozoa
Physical Examination:
Consistency:
Excess frothy, stable bubbles
frothy bloat/vagus indigestion
Physical Examination:
Sedimentation time:
How do we perform this test?
Allow fluid to sit in a test tube and determine the time for complete sedimentation and flotation of solid particles. Smaller particles sink, larger particles float on the bubbles of fermentation.
Physical Examination:
Sedimentation time:
normal range?
The normal range is 4–8 minutes
Physical Examination:
Sedimentation time:
What does active fluid show?
may exhibit sedimentation of fine particles with subsequent flotation
Physical Examination:
Sedimentation time:
What does inactive fluid show?
rapid sedimentation with little to no flotation, due to a lack of
fermentative gases
- rumen acidosis, prolonged anorexia (????)
Physical Examination:
Sedimentation time:
What does stable froth bloat show?
indicates frothy bloat or some types of vagal indigestions in the Hoflund disease (stenosis, hypermotility)
or in the case of treatment with
sympathomimetics (acetylcholine) used for the treatment of ruminal atonia.
Biochemical examination:
What do we examine?
- pH
- VFA
- reducing ability of anaerobic rumen flora
- Ruminal flora and fauna
- Ruminal fluid chloride
Biochemical examination:
pH:
When is it best to measure?
Best measured 2–4 hours after feeding concentrates or 4–8 hours after feeding a total mixed ration.
Biochemical examination:
pH:
How do we measure?
with pH paper or portable pH meter paper.
Biochemical examination:
pH:
normal pH?
range between 6.3–7 (slightly acidic)
cows fed grain can have slightly lower, those fed hay or green slightly higher pH
Biochemical examination:
pH:
elevated pH- why?
-Simple indigestion or reduced feed intake for greater than 2 days
-Urea indigestion
-Putrefaction of ruminal content from prolonged rumen stasis
- Saliva contamination
Biochemical examination:
pH:
Lowed pH - why?
-Grain overfeeding
-Chronic ruminal acidosis
Biochemical examination:
pH:
Things worth noting with pH
An animal with lactic acidosis may have a normal rumen fluid pH if anorexia has been
prolonged due to continued saliva production Abomasal reflux generally results in little to no change in rumen pH, making rumen chloride a better choice for evaluation.
Biochemical examination:
VFA:
name them
acetic acid
propionic acid
butyric acic
Biochemical examination:
VFA:
ratio
The average ratio at the pH 6-7 is 60-65% acetic acid, 20-25% of propionic acid and 10-15 mol% of butyric acid and 5 mol% other acids. In normal condition lactic acid is no present in the rumen fluid.
Biochemical examination:
VFA:
What does a decrease in VFA indicate?
a diet low in fiber or insufficient intake
AND
decreased activity of the microbial organisms
also high grain diet
Biochemical examination:
VFA:
how do we measure?
with high performance liquid gas chromatography (HPLC). It is the highest around 3 to 5 hours after feeding.
Biochemical examination:
VFA:
normal conc
The concentration of VFA in the rumen is between 80-120 mmol/l.
Biochemical Examination:
Reducing ability of anaerobic rumen flora:
What tests do we do?
nitrate
methylene blue
TTC
Biochemical Examination:
Reducing ability of anaerobic rumen flora:
when does the redox potential increase?
in a diet rich in starch and during ruminal acidosis
Biochemical Examination:
Reducing ability of anaerobic rumen flora:
When does the redox potential decrease?
when the ruminal flora is destroyed
Nitrate reduction test
- what do we test?
the capability of the ruminal bacteria to reduce nitrates and nitrites
Nitrate reduction test
- Chemicals
- potassium nitrate (KNO2)
- ad one drop of Griess-Ilosvay reagent (a mixture of alpha-naphthylamine and sulfanilic acid).
Nitrate reduction test
- colour change
In the presence of nitrite the color will be pink.
Nitrate reduction test
- when is the reaction more rapid?
Reduction is more rapid when cattle are fed green fodder or have ruminal decomposition or bloat, and slower when a deficient ration is fed or inapetence.
Methylene blue reduction test
- what do we test?
the reducing ability of the anaerobic rumen flora.
Methylene blue reduction test
- chemicals
methylene blue
Allow to stand and determine time taken to decolorize sample until only a blue ring remains at the top of the sample
Methylene blue reduction test
- normal
3–6 minutes; concentrate diets result in faster times, forage diets result in longer time of range
Methylene blue reduction test
- prolonged
Discoloration which takes longer than 10–15 minutes indicates inadequate anaerobic bacterial population, rumen acidosis or indigestible roughage.
Ruminal flora and fauna:
Types
protozoa
fungi
bacteria
protozoa
- types in rumen
ciliates and flagellates
but only ciliates are important
Protozoa
- are ciliates aerobic or anaerobic?
anaerobic
Protozoa
- functions
breaking down soluble sugars and various polysaccharides (starch, hemicellulose, xylane, pectin) or storing them
-they are capable to prevent rapid fall in ruminal pH by utilizing some starch that otherwise would be broken down by bacteria
-their active movement help at the mixing of the ruminal content
Protozoa
When is motility reduced?
in both acidosis and alkalosis
and in chronic processes
Bacteria
- conc
between 10.7 and 10.12 per ml of fluid rumen.
fewer- rich in cellulose
more - rich in startch
Bacteria
- categories and examples
The amylolytic and proteolytic bacterial flora comprises streptococcus and lactobacillus,
whilst streptococci, sarcina, spirillacea and selenomonas are fibrolytic.
Bacteria
- gram neg vs gram positive
neg - diet rich in fiber
pos - diet rich in starch
Fungi
- how can they be found
by Giemsa, PAS staining or culturing.
Rumen Ammonia
- what is it synthesised from?
protein and non protein nitrogen
Rumen Ammonia
- how is it absorbed?
through ruminal wall and into portal vein
Rumen Ammonia
- normal level
6-20 mmol/l
Rumen Ammonia
-what causes an increase?
- high protein intake
- energy deficiency
- liver disorders
increased nh3 leads to alkalosis and intox
Rumen chloride
- normal
15-20 mmol/l
Rumen chloride
- main source
saliva and diet
Rumen chloride
- when can the conc increase
In case of gastric torsion or in other cases ofpylorus obstruction the hydrogen chloride will pass into the rumen (reflux phenomenon) and can increase chloride up to 30-100 mmol/l.
Rumen chloride
- elevated