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Feeds and Feeding > Dairy Rations > Flashcards

Dairy Rations Flashcards

1
Q

What best determines productivity of lactating dairy cows?

A

Feeding

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2
Q

Feed represents how much of total feed cost?

A

~50%

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3
Q

Nutrient requirements for ____ are often several times the requirements for ____

A

lactation
maintenance

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4
Q

More variation exists in ____ content than ____ among various forages and concentrates

A

protein
energy

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5
Q

What to use when balancing dairy cow rations

A

NEL, CP, and fiber content

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6
Q

Can a producing dairy cow eat enough forage to meet her nutrient needs during lactation?

A

No

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7
Q

Feed intake may be stimulated by:

A

feeding several times per day
providing a variety of forages

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8
Q

Concentrate mixture includes:

A

grains
milk feeds
protein supplements
minerals

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9
Q

The mixture fed will depend on:

A

forage being fed (low protein forage = high protein concentrate)
availability
cost

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10
Q

Amount of concentrate fed will depend on:

A

amount of forage consumed
amount of milk produced
composition (% fat) of milk produced

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11
Q

Limit concentrate to a maximum of ____ regardless of comparative costs

A

65%

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12
Q

What happens when more than 65% of concentrate is consumed?

A

change in VFA production causing a decrease in milk fat

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13
Q

Concentrate intake can be affected by

A

palatability
time available to consume

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14
Q

Describe early lactation

A
  • milk production rapidly increases, peaking at 6-8 weeks after calving
  • increase grain intake to meet energy requirements, but avoid excessive levels (<65% of total DM)
  • extra dietary protein allows more efficient use of body fat for milk production since cows are usually losing BW
  • limit urea to 0.4-0.5 lb/d
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15
Q

Describe peak lactation

A
  • max intake is reached at ~12-14 weeks and cows should be kept at peak lactation as long as possible
  • grain intake may reach 2.5% BW, forage intake should be at least 1-1.25% BW to maintain rumen function
  • feed several times daily
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16
Q

Describe mid- to late lactation

A
  • milk production is declining, cow is pregnant
  • match grain intake to milk production ; avoid wasteful grain feeding to low producers
  • avoid overconditioning
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17
Q

Describe dry period

A
  • forage quality not as critical
  • DM intake ~2% of BW
  • ~2 weeks before calving increase grain feeding (~1% BW) ; helps decrease ketosis
  • feed low Ca ration to help prevent milk fever at calving
  • 4-8 week dry period, depending on age and physical condition
18
Q

Describe ketosis

A
  • high blood and urine ketone levels
  • low blood sugar
  • depleted glycogen reserve
  • LACK OF APPETITE
  • just giving glucose will not work in ruminants
  • propylene glycol is best - use steroids
  • high producing cow -> needs glucose for milk -> begins using body fat -> acetoacetic acid, b-hydroxybutyrate, and acetone -> KETOSIS!
  • cattle prone can be fed high quality before calving and increase substantially after parturition
19
Q

Describe milk fever

A
  • correlated with number of lactations
  • 75% of cases occur at or within 24 hours of parturition
  • decrease in blood Ca (hypocalcemia)
20
Q

Milk fever symptoms

A

drowsy
head turns to flank

21
Q

Milk fever treatment

A

IV calcium

22
Q

Milk fever prevention

A
  • low Ca diet 2-3 weeks before calving
  • Vit. D before calving -> BUT toxic so must know exact calving date
  • decrease DCAD (ratio of cations to anions in the diet)
23
Q

Feed young growing cows enough for …

A

growth as well as for maintenance and milk production

24
Q

It is best to group cows by ____

A

production level

25
Q

More cows are underfed on ___ than ____

A

energy
protein

26
Q

Concentrate mix should contain:

A
  • energy
  • protein
  • 0.5-1% trace mineralized salt
  • 1-2% Ca-P supplement
  • No more than 6% molasses
  • No more than 1% urea
27
Q

It is best to feed some ____ with silage

A

hay

28
Q

Fiber requirement

A

CF = ~17%
ADF/NDF = ~21%/35%

29
Q

Cow will consume ____ of water per lb of milk produced

A

3-5 lbs

30
Q

Relationship of feeds and milk flavor

A

remove from wheat pasture several hours before milking to prevent off-flavor

31
Q

2 protein sources ingested

A

CP and NPN

32
Q

2 protein sources available in the small intestine

A

bypass (from CP)
microbial (from NPN)

33
Q

DIP

A

Rumen Degraded Intake Protein
- degraded by microbes in the rumen
- microbial protein
- end up in SI

34
Q

UIP

A

Rumen Un-digestible Intake Protein
- by-pass/escape protein
- end up in SI

35
Q

Advantage for using DIP/UIP

A
  • decrease overall CP in diet
  • resulting in reduced cost of ration
36
Q

Describe Urea Fermentation Potential

A
  • evaluation of the useful urea in the ration
  • estimation of the g urea/kg DM that can be converted to microbial protein
  • value is dependent upon the energy in the diet
  • negative value indicates no protein would be synthesized with the energy available
37
Q

BST

A

bovine somatotropin = natural product produced in the pituitary (growth hormone)

38
Q

BST injected SQ every ____

A

14 days

39
Q

BST is FDA approved for healthy cows beginning

A

9th week of lactation

40
Q

BST injection results in

A
  • immediate (2-3 d) increased milk production (8-12% or 5-15 lbs milk/d)
  • Nutrients directed from body tissues to mammary gland
  • increased intake (nutrients) needed because of improved performance
  • DM intake not increased (as result of BST) until 3-6 wks post injection (3-5 lb/d) - usually results in decreased body condition
41
Q

BST effect on reproduction

A
  • increase days open (decrease pregnancy rate)
  • increase twinning
  • increase lameness (decrease bone and muscle mass)
  • increase mastitis

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