Lecture 5 Flashcards Preview

Ruminants > Lecture 5 > Flashcards

Flashcards in Lecture 5 Deck (34):
1

WHat does processing (chopping, grinding) of feed do to the pH of the rumen and why?

Decreases pH

Reduces chewing, increases saliva production

Increases fermentation rate by increasing surface area

2

3 affects of abnormal pH

Low pH decreases motility

Effects which microbes will grow or not grow

Decreases feed intake

3

What does saliva contains that helps with pH of rumen?

Lots of HCO3-

Phosphate buffers

4

How does rumen maintain an almost neutral pH?

1. Saliva

2. Carbonic anhydrase in rumen epithelial cells 

- Donates H to acid anion, absorbing acid from rumen to blood

- HCO3- left in rumen as buffer

3. Can add NaHCO3 to diet as a buffer

5

3 glands involved in saliva producion

Minor glands - mucus

Parotid Gland - Serous

Submandibular Gland - Mixed

6

What can occur to a ruminant with grain overload other than acidosis?

Rumen becomes hypertonic

H2O pulled in to rumen 

Systemic Dehydration

7

What produces CO2 in the rumen?

Decarboxylation

Carbonic Anydrase

8

What gasses are found in the rumen?

CO2 - 65%

CH4 - 25%

N2 - 7%

O2 - 0.5%

H2 - 0.2%

H2S - 0.01%

9

One way to reduce methane production?

Feed Ionophores

- H2 converted to propionate, not methane

10

Define Rumen Turnover

Amount of time required to replace the rumen contents with an equivalent volume

11

How do different feedstuffs affect rumen turnover?

Roughage diets - more rapid (3-7 times/day)

Grain Diets - slower (2-3 times/day)

12

What has the greatest influence on Rumen Turnover?

Salivation

Water Intake

13

What is solid turnover?

Rate of loss of solid material from the rumen

14

What determines solid turnover?

1. Digestibility of feed

- Grain digestibility = 90%

- Forage digestibily = 50%

2. Amount of feed

more feed = rumen distention = more motility

More motility = decrease time of digestion

15

How does feed intake affect energy intake?

More the cow eats the more energy intake

16

3 reasons why microbial efficiency might be increased with increased rumen turnover?

1. Increased rumen turnover favors faster growing bacteria so more protein produced

2. More bacteria in exponential phase of growth rather than maintenance

3. Decrease protozoa to eat bacteria when dilution rate increased (washed away with rumen material)

17

What is wrong with feeding pelleted dehydrated alfalfa to sheep?

Too much rumen turnover

- Goes full pellets go into GI which causes for GI to be hypertonic which pulls water in causes liquid feces

18

6 reasons why rumen environment is conducive to microbial growth

1. Acidity - pH is relatively constant

2. Temperature - Warm 39-40C

3. Motility - Mixes ingested feed with microbes and removes VFAs from site

4. Substrate and Moisture - Constant

5. Waste products - removed

6. Anaerobic

19

3 possible locations of rumen bacteria

Single Cells or Clumps (unattached) 50%

Attached to feed 

Attached to rumen epithelium

20

2 classes of bacteria in rumen

Primary Bacteria - directly ferment feed

-Amylotic

- Cellulolytic

Secondary Bacteria - Use byproducts produced by primary bacteria

 

21

What VFA does the following bacteria produce?

Fibrobacter succinogenes

Succinate

22

What VFA does the following bacteria produce?

Ruminococcus Albus

Acetate

23

What VFA does the following bacteria produce?

Selenomonas ruminantium

Proprionate (Randomizing)

24

What VFA does the following bacteria produce?

Methanobrevibacter

Methane

25

What VFA does the following bacteria produce?

Megasphaera elsdenii

Propionate (non-randomizing)

26

What VFA does the following bacteria produce?

Lactobacillus

DL Lactate

27

What VFA does the following bacteria produce?

butyrivibrio fibrisolvens

Butyrate

28

What do protozoa feed on?

Bacteria

Starch Granules

Protein

Fat

Cellulose and hemicellulose

29

Where are most protozoa found?

fibrous raft layer

30

What is protozoa a good indicator of?

Good health

31

What are the two major categories of protozoa?

Holotichs: Cilia cover entire body

Oligotrichs: Tufts of cilia at one end

32

What do fungi in rumen do?

Anaerobic and degrade

- Cellulose

- Starch

- Hemicellulose

- Some protein

33

When are fungi and yeast more important?

High Fibre diet

34

Affect of grain overload on protozoa?

DIE

protozoa are more sensitive to changes in rumen conditions