Dairy Nutrition II

Question 1

what is a transition cow?

Answer 1

3 weeks before and after calving, very vulnerable

Question 2

what is unique about the transition period?

Answer 2

adjusting moo to increased energy (grain)

Question 3

What percent should grain be limited to in a ration for dairy moos?

Answer 3

60%

Question 4

what is DMI influenced by?

Answer 4

stage of lactation, digestibility of fiber in diet, environmental conditions

Question 5

what does ADF measure?

Answer 5

lignin, cellulose - digestibility

Question 6

What does NDF measure

Answer 6

lignin, cellulose, hemicellulose - gut fill

Question 7

how is DMI affected by rumen fill?

Answer 7

eating a low digestibility diet (high ADF) rumen stays fuller longer so moo doesn’t want to eat

Question 8

how is DMI affected by level of production?

Answer 8

energy needs drive intake

Question 9

what can be used to estimate DMI?

Answer 9

120/NDF can be used to estimate DMI based on consumption of that feed

Question 10

how long do moos ruminate?

Answer 10

7-10 hours

Question 11

how long do moos needs to rest/lie down

Answer 11

10 hours

Question 12

what are the benefits of resting/lying down

Answer 12

rumination and eating goes up, stress on feet decreases, decrease lameness, increase blood flow to udder

Question 13

what happens when moo is resting <10 hours/d

Answer 13

milk production decreases

Question 14

what does it mean when a moo is perching?

Answer 14

can indicate lameness, uncomfy stall surface, bed is too short

Question 15

the space at the feed bunk should allow how many cows to eat at one time?

Answer 15

should allow 70% of cows to eat at one time

Question 16

what happens if there is decreased space in the feed bunk?

Answer 16

increased aggression, cows eat for shorter period, eat faster, eat more at night

Question 17

for every additional one pound of DM eaten, how much milk is made?

Answer 17

2.5-3 lbs more milk

Question 18

what is important about fiber for dairy cows?

Answer 18

long fibers are important to stimulate rumination

Question 19

what are structural carbs in forages?

Answer 19

lignin, cellulose, hemicellulose, pectin

Question 20

what are non structural carbs?

Answer 20

sugars, starch

Question 21

what are non fiber carbs?

Answer 21

beet pulp, citrus pulp

Question 22

how long should moos ruminate each day? (minimum value)

Answer 22

7-10 hours

Question 23

what is the highest yielding VFA produced from rumen?

Answer 23

acetate

Question 24

what is the lowest yielding VFA from rumen?

Answer 24

butyrate

Question 25

where does proprionate come from mostly?

Answer 25

mostly from NFC, particularly starch

Question 26

what is the main glucose precursor?

Answer 26

proprionate

Question 27

where is acetate mainly from?

Answer 27

mainly from structural CHO

Question 28

what is the main precursor for fat (adipose and milk)

Answer 28

acetate

Question 29

what is the precursor for fat and acetoacetate (ketone)

Answer 29

acetate

Question 30

what is the precursor for glucose?

Answer 30

proprionate

Question 31

what is the precursor for beta hydroxybutyrate (ketone)

Answer 31

butyrate

Question 32

what does Net energy account for?

Answer 32

energy loss from poo, pee, gas, and heat

Question 33

what is NEm

Answer 33

net energy for maintenance

Question 34

what is NEL

Answer 34

net energy for lactation

Question 35

as forage matures, what happens to NEL?

Answer 35

decreases

Question 36

for early lactation cows, what is the NDF recommendation from forage?

Answer 36

20-24% DM basis from forage

Question 37

for dry cows, what is the NDF recommendation from forage?

Answer 37

25% DM basis from forage

Question 38

moos need a minimum of what percentage of forage particles to be how long to stimulate rumination?

Answer 38

15-20% >1.5 inches

Question 39

why does 15-20% of forage need to be >1.5 inches long?

Answer 39

provides physically effective NDF

Question 40

how much peNDF is needed in dairy moos?

Answer 40

at least 22%

Question 41

why is rumen pH usually stable?

Answer 41

VFAs rapidly absorbed by papillae on rumen wall, bicarb in saliva buffers rumen pH

Question 42

what is subacute rumen acidosis?

Answer 42

prolonged periods of depressed pH (5.2-5.6)

Question 43

what causes SARA?

Answer 43

VFAs accumulate, but not persistent lactic acid accumulation; physio response to restore pH after many hours

Question 44

which moos are most susceptible to SARA?

Answer 44

transition moos

Question 45

insufficient peNDF reduces what?

Answer 45

reduces salivary production of buffer -> less rumination

Question 46

what is considered normal fluctuation for rumen pH?

Answer 46

normal for rumen pH to fluctuate 0.5-1pH units within a 24 hour perio

Question 47

what does pH of the rumen depend on?

Answer 47

intake of fermentable CHO, buggering capacity of the rumen, rate of VFA absorption in the rumen

Question 48

if pH falls below 5.5, what happens?

Answer 48

DMI will decrease as a protective mechanism - must recover before eating again

Question 49

what are signs of heat stress in moos?

Answer 49

panting, decreased activity, drooling, reduced intake

Question 50

what is the trend of rumen pH with cool temps and high roughage?

Answer 50

high pH

Question 51

what is the trend of rumen pH with high temps and high grain?

Answer 51

low pH

Question 52

what is soluble intake protein?

Answer 52

readily available nitrogen for microbes

Question 53

how is soluble intake protein provided?

Answer 53

provided by non-protein nitrogen source (urea)

Question 54

what is degradable intake protein/rumen degradable protein?

Answer 54

contains true proteins that are more slowly digested in the rumen

Question 55

what is undegradable intake protein/bypass protein?

Answer 55

protein that isn't rumen degradable by digested in SI

Question 56

what must be carefully balanced because microbial protein synthesis requires energy?

Answer 56

carefully balance CHO and RDP

Question 57

why is low quality forage and urea a bad combo?

Answer 57

low quality forage doesn't provide moo with enough energy for the microbes to effectively break down urea

Question 58

which cow is SASA a risk?

Answer 58

transition moo

Question 59

what percentage of microbial protein does the moo utilize?

Answer 59

utilize microbial protein for about 50% of protein requirement

Question 60

what protein is still needed in moo ration to meet remaining protein requirements?

Answer 60

rumen undegradable protein

Question 61

what percentage of fat doe base rations have?

Answer 61

3% fat

Question 62

what is the maximum fat in rations?

Answer 62

7% fat DM bais

Question 63

fat is rumen undegradable, so what does increased fat do to microbial protein synthesis?

Answer 63

decreases available CHO for microbial protein synthesis