RUMEN Digestion Flashcards
(44 cards)
Which side do you assess the rumen?
Left side
What is the main function of the rumen?
Fermentation of foodstuffs to produce…:
- Volatile fatty acids (VFA’s)
- Microbial proteins (synthesize by the bacteria)
- B Vitamins
(FERMENTATION: CORE FUNCTION OF THE RUMEN)
How do we mesure the feeding of ruminants?
With the dry matter (you DO NOT include the water component):
E.g.: 15 Kg DM –> Easier to give recommandation as a vet!
What does cellulose and hemicellulose turn into?
CARBOHYDRATES
Cellulose: starch + pectin
Hemicellulose: sugars
How is the carbohydrates metabolized?
BY THE BACTERIA IN THE RUMEN!
- Breaks them down into hexose –> 2 pyruvate –> Acetate, Butyrate, proprionate
What are the 2 big categories of carbohydrates?
Cell contents = non-fiber carbs or non-structural carbs (NFC/NSC) –> easily digested!
Cell wall = structural carbs = neutral detergent fiber (NDF)
What are the 2 components of NDF? Are they easily digestible like the NFC/NSC? Both digestible as easily?
- Hemicellulose
- Acid detergent Fiber: cellulose and lignin –> not digestible, need to limit those!
–> They are not as easily digested as NFC/NSC, they require specialize mechanisms to digest them!
Crude proteins is the name given to the protein being digested. What are the 2 main categories and subcategories of each? Are they all really able to be digested…?
So what are the metabolizable protein…?
RUMEN DEGRADABLE: (microbial protein synthesis)
- Non-proteins N fraction A
- AA & proteins Fraction B
RUMEN UNDEGRADABLE: (usually supplemented by the owner)
- AA & Proteins = absorption in the SI
- -> Part indigestible: lost in heat damages, complexed
It is the proteins that the ruminants can actually utilize.
- Rumen digestable and some rumen undigestable, but of those are lost!
What does NFC/NSC stimulate?
What does NDF stimulate?
For a balance rumen fermentation, what is the % of NDF, NFC and crude protein (CD) do you want to target? And why?
NFC/NSC: stimulate microbial digestion, therefore VFA production –> 40%
NDF: stimulates chewing, therefore saliva production (buffer) –> 30%
CP –> 17%
This formula will….
- increase VFA production = increase production (via NFC)
- Increase rate VFA production = decrease pH (via NFC again and lower % of NDF but not too much to keep buffer)
Is there a portion of the protein in the fecal material?
Yes! But need to minize it!
What is the main source of protein? Rumen digestable or undigestible?
Rumen degradable!
When bovins are eating they are ingesting big particles and later on (when not eating), what are they doing to make them smaller?
They are ruminating and fermenting the food. Bringing back food in the mouth to grinding them even more, and fermentation in the rumen.
What is a major source of lubrication? What is the other function of that thing?
Saliva! IMPORTANT Buffer substance! = key element for rumen function!!!!
If you change the diet of the ruminants, you have to do it….
gradually!!! The rumen is always adapting to the diet!
What does decreasing the size of the food does?
It increase the digestibility! Smaller piece = more efficient digestion!
How is the homoestasis of rumen maintained?
- Sources of buffer (epithelium, saliva)
- Effect of diet: VFA absorption
- Adaptation of the rumen all the time!
Is the epithelium of the rumen important?
Yes! The rumen epithelium acts as a buffer!
Why is a decrease of water supply will disturb the rumen function? How much acid does saliva absorbs (neutralize)?
Because it will decrease the saliva = decrease buffer HCO3- in the saliva.
Saliva neutralize 50% of acids produced!
So, now, what are the 3 element of constitutive control of Rumen pH?
And, what are the 3 element of inducible control of Rumen pH? (what you have control on)
Constitutive:
- VFA production
- Buffer from rumen epithelium
- Organic acid outflow
Inducible:
- VFA absorption
- Buffer from saliva
- Rumen microbiome
How does the rumen adapt? To what is it adapting?
Increase rumen mass and papillae size!!! It adapt to a change in diet, for example, in this case, it to an increase in dry matter intake.
Important to keep a precise pH range, how do ruminants do it?
Buffer inside the saliva!!
Major source of bicarbonate! + lubricate the food!
120L per day!
Neutralize 40-50% of acid produced
Need more water when producing milk = more water!
How do you ensure a good amount of saliva production?
Provide clean and ad lib water!
What can rumination time influence?
What can influence rumination time?
What affect the dry matter intake (DMI)?
- -> Increase ruminating = increase rumen pH (protect from acidosis)
- -> Increase NDF/peNDF = increase ruminating = increase saliva production = more buffer (also protect from acidosis)
NDF and peNDF affect DMI!
What is the main source of carbs use?
What does an increase of NFC/starch does?
Why is the rate of degradation of those NFC important? How do you control it?
CORN!
- Increase NFC/startch = decrease rumen pH
The rate of degradation is important for a good absorption and you can control it by fine chopping Alf silage and corn silage.
