3 Nutritional Management 1 Flashcards

1
Q

What is the role of grains?

A

Optimize rumen fermentation to maximize production

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2
Q

Different types of forage

A

Legume, grass, straw, barley silage, corn silage

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3
Q

Nutrient composition of the forage types

A

Legume: high NDF, high CP

Grass: high NDF

Straw: highest NDF

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4
Q

Compare CP, NDF and starch contents of barley vs corn silage

A

Barley:
10-15% CP
45-55% NDF
10-25% starch

Corn:
8-12% CP
40-50% NDF
5-30% starch (higher, but larger variation)

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5
Q

Why is barley silage used? When is it grown & harvested?

A

Agronomically more predictable than corn

Grows May to August
Harvested as whole crop silage at mid-dough stage

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6
Q

Why is corn silage used? What does it depend on

A

Greater yield
Environmental conditions affect starch content, plant growth and kernel filling

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7
Q

What are Corn Heat Units (CHU)

A

Measure of the heat accumulated over the growing season specific to the physiological needs of a corn plant

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8
Q

What is used to calculate CHU?

A

Minimum and maximum temperatures

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9
Q

When does no growth occur for corn plants?

A

Night temps (min) below 4.4C
Day temps (max) below 10C

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10
Q

What happens when CHU is low?

A

There is a greater risk of killing frost before corn matures

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11
Q

What is the milk line?

A

White line in corn
For silage, harvest when milk-line is in the middle

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12
Q

When is corn silage more digestible?

A

> 12 weeks after harvest
do not feed right after harvesting, there is poor digestibility

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13
Q

Why does corn silage become more digestible over time?

A

Starch granules are embedded in a protein matrix
Protein matrix solubility increases with time (less protective wall) = increased digestibility

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14
Q

Three types of silage storage

A

Upright silo
Ag-bag
Bunker silo

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15
Q

How is silage preserved?

A

fermentation and production of lactic acid (inhibits decomposition of the herbage until feeding)

25-50% dry matter anaerobically stored (high moisture = good environment for lactic acid producing bacteria)

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16
Q

Slide 25*

A

Ensiling process (confusing)

17
Q

Four important characteristics of silage storage environments

A
  • sugar (fermentable CHO to make lactic acid)
  • moisture (50-75%)
  • correct pH (4.0)
  • no oxygen
18
Q

Nutrient losses associated with ensiling

A
  • plant respiration
  • CO2 production (initial fermentation)
  • seepage (moisture content)
  • secondary fermentation (aerobic fermentation by yeasts and molds in silage exposed to oxygen at silo face)
19
Q

Losses associated with silage vs hay

A

Silage = storage loss
Hay = harvest loss

20
Q

How much moisture in hay? Why?

A

<20%
safe storage without mold

21
Q

How are nutrients lost during hay harvest?

A

When drying in the field, leaves easily fall off the stem. When collected, leaves may fall off and only stem is collected

Leaves contain more protein and are more digestible
Stems contain more fiber and are less digestible

22
Q

Nutrient losses associated with hay (5)

A
  • shattering (loss of energy and protein when leaves fall)
  • plant respiration
  • rainfall or leaching loss
  • bleaching (sun curing)
  • losses at feeding
23
Q

Pros of feeding grains to ruminants

A
  • high in digestible E
  • low cost / kg of digestible energy (in general)
  • decrease need for on-farm storage
  • easy to feed
24
Q

Cons of feeding grain to ruminants

A

Risk of rumen acidosis / lameness

25
Q

Structural differences between corn grain and barley grain

A

Corn grain: starch is protected by a prolamin protein

Barley grain: starch is protected by fibrous hull layer

26
Q

Where does barley grain ferment? Corn grain?

A

Barley = rumen
Corn grain = digested more in small intestine

27
Q

How can grain decrease feed intake?

A

Grain with greater rumen fermentation (barley) decreases feed intake

28
Q

Feed intake of corn vs barley grain

A

Barley has greater rumen fermentation decreases intake
When fed the same amount of corn & barley grain, animal will eat more corn

29
Q

Slides 45-59

A

Grain studies

30
Q

Two ways of processing grain

A

Grinding (use of a hummer mill)
Rolling

31
Q

Why do we process barley grain?

A

Expose the endosperm (break the fiber layer) which makes it more digestible

32
Q

What does the processing index tell us?

A

How volume weight changes through processing

32
Q

What factors affect an animals response to being fed grain

A
  • dietary grain allocation
  • starch content of diet
  • type of grain (corn vs barley)
  • extent of processing