Rumen ecology

Question 1

how to define rumen compartment

how many rumen contractions/min

Answer 1

-dynamic, continuous fermentation compartment
-provides suitable environment for: anaerobic bacT, fungi and protozoa

1-3/min in healthy animal!!

Question 2

feed converted to ??

Answer 2

microbial matter and fermentation end products - want good bacT to proliferate

Question 3

rumen colonization - each interaction adds??
can rumen microorganisms manufacture protein from non protein nitrogen?

Answer 3

bacT to rumen - from grooming, feeding etc.
YES!

Question 4

rumen microbes ferment X to produce what 3 things??

Answer 4

ferment foodstuff to produce VFA, microbial proteins and B vitamins

feed gets absorbed by rumen microbes and converted to energy

Question 5

3 VFAs

Answer 5

acetate, butyrate, proprionate

Question 6

carbs in grass –> 2 pyruvate –> 3 outcomes

Answer 6

1. acetyl coA –> acetate and butyrate
2. proprionate
3. lactate –> proprionate

Question 7

plant carbs - cell wall

Answer 7

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

Question 8

protein -rumen degradable vs. rumen undegradable

Answer 8

degradable: part that is metabolized from microbial bacT
undegradable: bypass rumen to get to SI, similar to monogastric

Question 9

plant nutrients comparison?

Answer 9

based on DM!!
increase H2O = less DM for bacT to utilize
-want least amount of rumen undegradable protein

Question 10

increase total VFA = what to production?
increase RATE of VFA production = what to pH???

Answer 10

increase VFA = increase production

increase rate of VFA production = decrease pH

Question 11

ruminal homeostasis impacted by what 3 things?
GOAL?

Answer 11

1. sources of buffer (prevent extreme pH)
2. effect of diet (transition diets)
3. adaptation (control rumen microbiome)

maintain optimal ruminal envi!!!

Question 12

control of rumen pH (3 things)

Answer 12

VFA absorption, buffer from rumen epithelium (absorbs VFA and prevents bacT from getting out of rumen), organic acid outflow (Saliva recycling)

Question 13

rumen adaptation for ?
what happens (3 things) in the adaptations

Answer 13

more efficient absorption
-rumen must increase in size to keep up with milk production

1. increase rumen mass
2. thin cell layer - to absorb more
3. increase in papillae - to increase SA of absorption that helps with Butyrate metabolism and nuclear receptors responding to SCFA

Question 14

inducible control of rumen pH (3 things)

Answer 14

1. VFA absorption
2. buffer from saliva - cattle produce 40-250 L of saliva/day, which buffers rumen pH
3. rumen microbiome

Question 15

how much saliva do dairy cattle produce

Answer 15

250 L/day - need more nutrients because high producing

Question 16

rumination time:
-increase rumination = does what to rumen pH
-increase NDF = does what to rumination

Answer 16

increase rumination = increase rumen pH
increase NDF = increase rumination

Question 17

rumen microbiome breaks down feed to produce ??

Answer 17

VFA
-must adapt animal to feed!

Question 18

altered ruminal ecosystem results in (6) things:

Answer 18

1. bloat (excess gas in rumen)
2. rumen acidosis (decrease in rumen pH)
3. hypoglycemia (less glucose uptake)
4. diarrhea (dehydration and lose of BCS)
5. ulcers in GIT (lose GI epithelium barrier)
6. reticuloperitonitis aka hardware disease

Question 19

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

Answer 19

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

Question 20

acute acidosis causes

Answer 20

lactate accumulation in rumen –> leads to systemic problem
-ends in low rumen pH and dead rumen because no bacT can survive

Question 21

rumen epithelium - transition period

Answer 21

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

Question 22

rumenocentesis
sampling times?
should be sampling rumen pH how often?

Answer 22

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