Ruminant Nutrition Flashcards
What are the functions of the stuctures of the mouth
Mouth: dental pad/prehend with lower incisors and tongue/mastication with cheek teeth
What are the features of saliva
- Saliva: continuous production (70-90% rumen fluid) – urea (N) and buffers (HCO3)
o No amylase
What are the 4 compartments of the stomach and their functions
- Reticulum: transport food into rumen and omasum
- Rumen: fermentation
a. Ruminal contractions: ruminal pillars/circulation of ingesta/regurgitation - Omasum; water absorption/small particulate passage
- Abomasum: glandular
Define rumination
b. Rumination: fibre content and particle size
Define eructation
c. Eructation: gas produced removed
Differentiate starch from cellulose
starch
- connected by alpha 1-4 bonds
- mammals have alpha amylase
beta
- connected by beta 1-4 bonds
- mammals don’t have beta cellulase (bacteria do)
What is the main VFA produced by rumen fermentation regardless of feeding
acetate
What is the most important VFA
propionate (3 carbons) because it is the only VFA that forms glucose (gluconeogenesis)
the other VFA (acetate - only 2 carbons/butyrate - 4 carbons) form ATP in krebs cycle (not glucose)
What is the main source of protein/amino acids to ruminants
microbial protein
What is the nutrient value of crude protein
source of nitrogen
What are ruminal microbiota? What are their function
Ruminal Microbiota: symbiotic anaerobiotic microorganisms
* Fermentation
What is the composition of ruminant rumen microbiota
- Bacteria: 50-60%
- Protozoa: 40-30%
- Fungi: 5%
- Archaea: 4%
List the 3 main factors influencing microbiota in rumen
Factors
* Rumen environ (pH)
* Substrate/diet
* Resistance to end-products (VFA)
What do bacteria require to live/reproduce? What are their end products?
Bacterial requirements
* Energy/carbs: fibre/non-fibre
* Nitrogen: ammonium/amino acids/peptides
* Form volatile fatty acids + methane + carbon dioxide + heat
What is the main non-carb energy sources for cows? How are they processed
Cow energy source: gluconeogenesis
* Propionate used for gluconeogenesis = make glucose
o Result in 36 ATP in krebs cycle
* Amino acids/glycerol/lactate can also be used for energy
What is one main factor that can reduce rumination
acidosis
What are 3 factors that affect dry matter intake
Factors affecting dry matter intake
* Rumen fill
* Environment temp
* Water availability
What are 3 factors affecting rumen fill
o Forage quality: fibre digestibility
Neutral detergent fibre (fibre)
o Forage growth stage
List 3 examples of structural and non-structural carbs. List common sources of each
- Structural: cellulose/hemicellulose (NDF)/cellulytic microbiota
o Pasture/hay/straw/haylage/silage - Non-structural: starch/sugar/amylolytic microbiota
o Barley/corn/wheat/sorghum
What is acetate? How is it metabolized? What is it used for?
- Acetate: 2 carbon = fibre
o Used in kerbs cycle to make acetyl co-A then to ATP and fatty acids
o Precursor for milk
What is butyrate? How is it metabolized? What is it used for?
- Butyrate: 4 carbon = starch
o Used in kerbs cycle to make acetyl co-A then to ATP and fatty acids
o Metabolized in rumen as energy
o Makes ketone bodies
What is proprionate? How is it metabolized? What is it used for?
- Propionate: 3 carbon = starch
o Used in gluconeogenesis (main energy source)
o Precursor for milk lactose
What are the main sources of protein for ruminants
- Crude protein: true protein from feed
o Rumen degradable protein
o Rumen non-degradable protein: microbes digest - Non-protein nitrogen: urea
o Important in low nitrogen environment conditions - Most from microbial protein
List 3 sources of crude protein in ruminant diet
o Canola meal/soybean meal/distillers grain
