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Feeds lecture > Dairy Nutrition > Flashcards

Dairy Nutrition Flashcards

(66 cards)

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1
Q

what state ranks 1st in dairy cow inventory

A

california

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2
Q

where does Texas rank in terms of dairy cattle inventory

A

4th

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3
Q

what percent of total US dairy inventory does Texas hold

A

6.8%

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4
Q

trend of average dairy herd size and number of herds

A

size has increased and number has decreased

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5
Q

what are NE values affected by

A

-nutrition composition of feeds
-physiological function of animal

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6
Q

how does nutritional composition of feed affect NE

A

fiber has higher heat increment

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7
Q

which has a higher heat increment: growth or lactation

A

growth

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8
Q

T/F NE for lactation will always be higher? why/why not?

A

TRUE, heat increment is low

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9
Q

equation for NE

A

NE = ME- HI

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10
Q

T/F lactating cattle are less efficient than growing cattle

A

FALSE. they are more efficient

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11
Q

why is it impossible to meet lactating cows nutrient demands

A

demands exceed DMI

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12
Q

how do dairy cows meet nutrient requirements when feed doesnt

A

mobilization of fat

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13
Q

dairy cow production phases

A
  1. early lactation
  2. mid lactation
  3. late lactation
  4. dry period
  5. transition period
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14
Q

early lactation characteristics

A

-0-10 wks
-peak milk production at 3-6 wks

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15
Q

mid lactation characteristics

A

-10-24 wks
-milk yield begins to decrease
-peak DMI at 11-13wks

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16
Q

late lactation characteristics

A
  • > 24 wks
    -decreased milk yield
    -cow regains body tissue reserves
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17
Q

dry period characteristics

A

-5-8 wks
-late pregnancy

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18
Q

transition period characteristics

A

-2-3 wks
-late pregnancy
-prepare for lactation

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19
Q

how does lactation rank in physiological priority throughout milking phases

A

Early: highest priority
Middle: 2nd(behind repro)
Late: lowest(repro, growth, maintenance)

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20
Q

issue with feeding high grain diets to dairy cows

A

damage to rumen papillae and depress milk fat

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21
Q

milk fat thresholds for $/cwt increase

A

.1% above 3.2%
bonus .1% over 3.5%

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22
Q

what factors are producers paid based on

A

milk volume
milk composition
milk quality

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23
Q

what threshold of milk quality are producers paid extra

A

$.03 per 20,000?l below somatic cell count of 400,000/L

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24
Q

how does rumination affect digestion

A

salivation increases rumen pH, increased pH is favorable for fiber loving microbes

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25
why is the acetate:propionate ratio important
acetate helps with milk fat production
26
what rumen pH does acetate prefer
higher pH
27
what rumen pH does propionate prefer
lower pH
28
rule of thumb for adequate fiber levels
-forage:concentrate ration of 40:60 -minimum 21% ADF -minimum 1-1.5% BW as forrage
29
what is effective fiber dependent on
-particle size(larger=effective) -amount of chemical fiber(CF, ADF, NDF) -type of fiber(amount lignin)
30
how does effective fiber affect rumination
increased effective fiber increases rumination
31
how does the roughage index value effective fiber
measures amount of time cow spends ruminating(calculated as minutes chewing per unit DM)
32
methods to measure effective fiber
-roughage value index -particle size separator -sensor technologies
33
how does the particle size separator measure effective fiber
sorts into large, medium, and small large:6-10% medium:30-50% small:40-60%
34
how do sensor technologies measure effective fiber
collar monitors rumination
35
what reproduction phase will the cow have a drop in feed intake
a few days before calving
36
short term benefits of proper fiber
increased milk fat synthesis
37
long term benefits of proper fiber
prevent acidosis and rumen burnout
38
nutritional factors(other than fiber) that affect milk composition, and how?
-type of grain: faster fermentable grains increase milk depression -grain processing: more processed = faster fermentation -dietary buffers: increase rumen pH to minimize milk fat depression -dietary fats: decrease milk protein
39
grain rates of fermentation(fastest to slowest)
Fastest: Wheat Barley Slower: Milo, Corn
40
situations where dairy buffers are beneficial
high corn-silage diets high grain diets low effective fiber diets cows off feed(early lactation)
41
what and how much buffer can be fed to cows
sodium bicarbonate @ 1% of DM
42
how much fat can you add to cattle diet
5%, most feeds contain 3% fat
43
issues with adding more than the acceptable amount of fat to the diet
-decreased feed intake -decreased fiber digestion -increased digestive upset
44
how much fat is acceptable in cow diets
8%
45
benefits of adding fat to dairy cows
-increased milk production -less weight loss -less impacted by heat stress -decreased heat increment -reduce ketosis -enhance reproductive performance
46
cheapest fat sources
plant seed oils
47
most expensive fat sources
processed fat sources
48
mid range fat sources
unprocessed fat
49
purpose of bypass fats
dont disrupt rumen fermentation of fiber
50
feeding systems for lactating dairy cows
Traditional TMR
51
disadvantages of traditional feeding system
estimating forage DMI and nutritional quality makes it difficult
52
what is the traditional feeding system
forage and concentrates fed separately
53
what is Total mixed ration feeding system
forages and concentrates mixed together
54
disadvantages of TMR
all forages must be harvested
55
advantages of TMR
-cows dont choose which forage to eat(cows are forced to eat correct balance of forage and concentrate) -multiple small meals help maintain stable pH -easier to feed various production groups -reduce incidence of social dominance
56
advantages of traditional feeding system
-no need for harvesting forages -equipment is less expensive
57
new method for preventing milk fever
dietary cation-anion balance(DCAB)
58
how does DCAB work
negative DCAB before calving lowers milk fever(feed negative balance during stage 5)
59
cation(alkalogenic) macrominerals
Na and K
60
anion(acidogenic) macrominerals
Cl and S
61
what is the recommended DCAB
-10 to -15 meq/100 g diet DM
62
challenges to feeding negative DCAB
-anion salts are more expensive -anion slats are less palatable
63
symptoms of ketosis
-elevated ketone bodies -depressed blood glucose levels -decreased appetite -decreased milk production -distinctive acetone
64
T/F ketosis is very deadly to dairy cattle
FALSE. cows rarely die from it
65
occurrence of ketosis
-2-15% get clinical ketosis -50% get borderline ketosis -most cases occur within 60 days of calving
66
prevention of ketosis
-avoid excess BCS at calving -good transition diet -maximize DMI during early lactation -feed glucose precursors -feed niacin(b-complex vitamin)

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