Lecture 36 - Physiology of the rumen Flashcards
describe glandular enzymatic digestion
- starch
- host origin
- rapid, incomplete
- stomach, small intestine
- simple sugars, amino acids, fatty acids
describe fermentative enzymatic digestion
- starch, cellulose
- microbial origin
- slow, complete
- rumen, cecum, colon
- VFAs and methane
rumen microflora can be considered as
one functional organism
describe the fermentation of carbohydrates from polysaccharide to butyrate
- polysaccharide
- glucose
- acetate
- propionate
- butyrate
describe acetate
- 60-70% of VFAs
- forage
- increases methane production
- not removed by liver (increase milk fat)
describe propionate
- 20-30% of VFAs
- grain
- does not influence methane production
- completely removed by liver (drives milk volume)
T/F: microbes are digested in the abomasum and small intestine to maintain protein:carbohydrate balance
TRUE
CH2O + protein =
VFAs, CO2, CH4, microbes
if pH is less than 5.5, what is likely occurring in the rumen
- too much grain
- rapid fermentation
- protozoa die and bacterial population shifts to produce lactic acid
if pH is more than 5.5, what is likely occurring in the rumen
- anorexia, poor feed
- outflow obstruction
rumen motility is required for what 4 things
- facilitate fermentation
- allows for rumination
- move digested food out of the rumen
- remove byproducts of fermentation
what stimulates the vagus nerve in ruminants
- feeding (buccal receptors)
- moderate rumen distension (low threshold receptors in reticulum and dorsal sac)
what is inhibitory for the vagus nerve in ruminants
- moderate to severe rumen distension (high threshold in rumen)
- increase VFA concentration-low pH
- pain
- fever, endotoxemia
T/F: control of secondary contractions is autonomous
TRUE
what stimulates secondary contractions
distension of dorsal sac
what inhibits secondary contractions
- severe distension
- fluid at cardia
- damage to cardia receptors
- systemic disease
- failure of esophageal transport
T/F: ruminant time does not depend on feed consistency
FALSE
rumination occurs before
primary or secondary contraction
describe omasal motility in 4 steps
- filter based on particle size
- negative pressure sucks ingesta in
- canal contracts with dorsal sac
- omasal body contracts
describe vagal indigestion syndrome symptoms
- retention of fluid
- hyper-/hypo- motility
- severe abdominal distension
type 1 vagal indigestion
- failure to eructate
- large gas-filled rumen, left side distension
type 2 vagal indigestion
- failure of rumen/reticulo-omasal outflow
- large fluid-filled rumen, distension on both sides
- rumen pH and Cl- are normal
type 3 vagal indigestion
- failure of abomasal/pyloric outflow
- large fluid-filled rumen, distention of both sides
- serum Cl- decreased
- serum Cl- and bicarbonate increased
how are types I and II vagal indigestion treated
left flank exploratory and rumenotomy
how is type III vagal indigestion treated
right flank exploratory
what are the 3 primary patterns of motility
- mixing
- excruciation
- ruminantion
