Rumen ecology Flashcards
how to define rumen compartment
how many rumen contractions/min
-dynamic, continuous fermentation compartment
-provides suitable environment for: anaerobic bacT, fungi and protozoa
1-3/min in healthy animal!!
feed converted to ??
microbial matter and fermentation end products - want good bacT to proliferate
rumen colonization - each interaction adds??
can rumen microorganisms manufacture protein from non protein nitrogen?
bacT to rumen - from grooming, feeding etc.
YES!
rumen microbes ferment X to produce what 3 things??
ferment foodstuff to produce VFA, microbial proteins and B vitamins
feed gets absorbed by rumen microbes and converted to energy
3 VFAs
acetate, butyrate, proprionate
carbs in grass –> 2 pyruvate –> 3 outcomes
- acetyl coA –> acetate and butyrate
- proprionate
- lactate –> proprionate
plant carbs - cell wall
cell wall has cellulose and lignin
increase feeding of those = less digestible because expend more E to digest feed
-must be fermented before they can be utilized
protein -rumen degradable vs. rumen undegradable
degradable: part that is metabolized from microbial bacT
undegradable: bypass rumen to get to SI, similar to monogastric
plant nutrients comparison?
based on DM!!
increase H2O = less DM for bacT to utilize
-want least amount of rumen undegradable protein
increase total VFA = what to production?
increase RATE of VFA production = what to pH???
increase VFA = increase production
increase rate of VFA production = decrease pH
ruminal homeostasis impacted by what 3 things?
GOAL?
- sources of buffer (prevent extreme pH)
- effect of diet (transition diets)
- adaptation (control rumen microbiome)
maintain optimal ruminal envi!!!
control of rumen pH (3 things)
VFA absorption, buffer from rumen epithelium (absorbs VFA and prevents bacT from getting out of rumen), organic acid outflow (Saliva recycling)
rumen adaptation for ?
what happens (3 things) in the adaptations
more efficient absorption
-rumen must increase in size to keep up with milk production
- increase rumen mass
- thin cell layer - to absorb more
- increase in papillae - to increase SA of absorption that helps with Butyrate metabolism and nuclear receptors responding to SCFA
inducible control of rumen pH (3 things)
- VFA absorption
- buffer from saliva - cattle produce 40-250 L of saliva/day, which buffers rumen pH
- rumen microbiome
how much saliva do dairy cattle produce
250 L/day - need more nutrients because high producing
rumination time:
-increase rumination = does what to rumen pH
-increase NDF = does what to rumination
increase rumination = increase rumen pH
increase NDF = increase rumination
rumen microbiome breaks down feed to produce ??
VFA
-must adapt animal to feed!
altered ruminal ecosystem results in (6) things:
- bloat (excess gas in rumen)
- rumen acidosis (decrease in rumen pH)
- hypoglycemia (less glucose uptake)
- diarrhea (dehydration and lose of BCS)
- ulcers in GIT (lose GI epithelium barrier)
- reticuloperitonitis aka hardware disease
acute acidosis is
also have subacute ruminal acidosis (SARA)
-what does SARA do ?
what else can SARA affect?
SARA inflammation ?
SARA systemic effects (3 things)
optimal rumen pH
metabolic status defined by decreased blood pH and bicarbonate, caused by overproduction of ruminal D lactate aka lactic acidosis caused by grain overload
SARA: change from optimal pH
-reduces DM intake
-decrease ruminal contractions
-both lead to static rumen = reduction in rumen with lowered pH
-affects cecum as well = mucosal damage
-pro inflammatory activating and puts liver in overdrive
systemic effect:
1. laminitis: lameness = wont eat = decrease production =change rumen environment
2. liver abscesses = not efficient metabolism and liver condemned
3. caudal vena caval syndrome = occlusion and sudden death
optimal pH: 5.5-7
acute acidosis causes
lactate accumulation in rumen –> leads to systemic problem
-ends in low rumen pH and dead rumen because no bacT can survive
rumen epithelium - transition period
3 weeks before calving to 3 weeks after calving
-big changes during transition period because animals fed two different diets
-3 wks: thick epithelium with thick wall
+1 wk: thin epithelium to increase absorption
rumenocentesis
sampling times?
should be sampling rumen pH how often?
8 hours post feeding TMR herd
3 hours post concentrate feeding in component fed herd
get fluid and record pH
measure often, may need to intervene - can use accelerometers and rumination monitors
