Rumen

Question 1

Describe the rumen.

Answer 1

-dynamic, continuous fermentation compartment
-suitable environment for:
>anaerobic bacteria
>Protozoa
>fungi
—feed converted to microbial matter & fermentation end products

Question 2

Describe rumen colonization.

Answer 2

-rumen microorganisms manufacture protein from non protein nitrogen
-ferment foodstuff to make:
1. VFA
2. Microbial proteins
3. B vit

Question 3

Describe plant protein & carbohydrates.

Answer 3

Question 4

Describe plant nutrients.

Answer 4

Question 5

Describe how rumen fermentation changes.

Answer 5

1. NDF 50% NFC 20% CP 14%
2. NDF 30% NFC 40% CP 17%
   -inc total VFA/day = inc production
   -inc rate VFA production = dec pH

Question 6

Describe rumen homeostasis.

Answer 6

-source of buffer
-effect of diet
-adaption
*maintain optimal ruminal environment

Question 7

Describe the control of rumen pH.

Answer 7

1. VFA production
2. Buffer from rumen epi
3. Organic acid outflow
   -75-85% VFA -> rumen = salivary HCO3 supply 50% absorbed acids

Question 8

Describe rumen adaptation.

Answer 8

1. Inc rumen mass
2. Thin cell layer
3. Inc in papillae
   >butyrate metabolism
   >nuclear receptors responding to SCFA

Question 9

Describe the control of rumen pH.

Answer 9

1. VFA absorption
2. Buffer from saliva
   -neutralize 40-50% acid made
3. Rumen micro biome
   cattle make 40-250L* of saliva per day to buffer rumen pH

Question 10

Describe rumination time.

Answer 10

-inc ruminating = inc rumen pH
-inc NDF/peNDF = inc ruminating
-NDF & peNDF affect DMI

Question 11

Describe the rumen micro biome.

Answer 11

-break down feed to make VFA *
-all forage
>acidosis = ground barley

Question 12

Describe CHO source.

Answer 12

-inc NFC/starch -> dec rumen pH
-rate of degradation imp

Question 13

Describe the effect of grain source.

Answer 13

Question 14

Describe altered rumen ecosystem.

Answer 14

1. Acute acidosis
   -dec blood pH & bicarb due to overproduction of ruminal D-lactate
   -lactic acidosis, grain overload
2. Sub acute ruminal acidosis (SARA)
   NORMAL RUMEN PH IS 5.5-7

Question 15

Describe acute acidosis.

Answer 15

-lactate accumulation
>rumen & systemic
—rumen pH 4.2-5 *
—blood pH 7-7.2 *
—dead rumen

Question 16

Describe SARA ruminal pH & DMI.

Answer 16

<5.5 for >3hr/day
<5.8 for >5hr/day

Question 17

Describe the rumen epithelium.

Answer 17

Transition period = 3wk before calving to 3wk after calving *

Question 18

Describe SARA & the cecum.

Answer 18

-inc starch
-inc VFA
-dec pH
-mucosal damage *
—inc caspase 3 & 8
—inc MyD88, NFkB
>LPS -> TLR4 -> MyD88 ->NFKB

Question 19

Describe SARA & inflammation.

Answer 19

-inc LPS rumen, binding protein in blood, portal vein
-inc cytokines portal vein: IL1B, IL6, TNFa *
-inc cytokines liver: ILa, IL1B, IL6, TNFa, IL10
-inc acute phase proteins: haptaglobin, serum amyloid A

Question 20

Describe SARA systemic effects.

Answer 20

1. Laminitis = inflam of lamina corium of hoof & corium of sole
2. Liver abscess
   -12-32% in feedlots
   -cd vena cava syndrome = sudden death *

Question 21

Describe rumenocentesis.

Answer 21

-sample time
>8h post feeding in TMR herd *
>3h post conc feeding in component fed herd *
-sample method
>percutaneous aspiration
>pH meter

Question 22

Describe acidosis & other digestive problems.

Answer 22

Question 23

Describe SARA threshold test.

Answer 23

-15 cows
>distinguish 1st lactation VS older
>fed same diet
>housed similarity
>14-200 DIM
-if 4/15 rumen samples pH 5.5 take action *
-not an estimate of prevalence
-reasonable accuracy
>error offset by feasibility & potential cost of inaction

Question 24

Describe the technologies for pH monitoring.

Answer 24

-ideal measure time pH <5.6/5.8
-current impediments for on farm use
>cost 1k
>life span 6mo
>one time use
HIGH TECH:
1. Accelerometers: position not just steps
-dec activity w disease/lameness
2. Rumination monitors
-normal >450 min/day

Question 25

Describe the prevention via diet formulation.

Answer 25

-assess grain >rate starch digestion >6hr DM disappearance >acidosis index {(6hr starch disappearance x starch %)x[total in vitro acid prod+(2x in vitro LA prod)] – 0.55xNDF} x 1.3

Question 26

Describe grass quality.

Answer 26

-change sparingly >forage availability & quality -supplemental hay for high risk periods

Question 27

Describe temperature management.

Answer 27

-thermal neutral zone 40-68c -host weather >dec rumination time >alter feeding pattern

Question 28

Describe diet.

Answer 28

1. Ionophore -control gram pos bacteria -inc feed efficiency -no effect on rumen pH 2. Dietary buffers -+DCAD, not rumen pH 3. Fungal/yeast extract/culture -aspergillus oryzae -saccharomyces cerevisiae