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VETM 465 Nutrition > Dairy Nutrition 3 > Flashcards

Dairy Nutrition 3 Flashcards

1
Q

What are the energy needs for dry cows

A
  • Maintenance
  • Fetal growth
  • Colostrum production
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2
Q

What are the goals for feeding dry cows

A

Goals
* Control BCS
* Optimize dry matter intake
* Ruminal adaptation for lactation
* Reduce metabolic disorders post-birth

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3
Q

What is the timeline for a year for a dairy cow? How is nutrition and BCS impacted

A
  • 0d = calve
    o Decreased DMI close to calving
  • 0 – 30d = rest post-parturition – then begin breeding
  • 100d = breed (9 months before drying out) – should be pregnant
  • 1-305d = milk production
    o Start with 15L/d – slowing increase production (peak at 60d)
     Most susceptible period
    o 1st 2 month (pre-peak production) = low DMI (negative energy balance) = low BCS
    o After they reach peak milk production – they eat more DMI than energy expended = regain BCS
  • 305 - 365d = dry (60d)
    o ‘dry out’ cow by reducing milking
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4
Q

What to consider when feeding a dry cow? How does the timeline of the cow affect feeding?

A
  • Control energy intake – will eat more than they need
  • Far off group: 60d before calving
    o 1.2 Mcal/kg with 12-13% CP
    o Minimal grain – high forage
  • Close up group: 21d before calving
    o 1.5 Mcal/kg with 14-15% CP
    o Lower dry matter intake, higher energy requirement
    o Silage based (higher grain)
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5
Q

What is the max BCS loss you should see for a dairy cow

A

1 point

ideally 0.5 - 0.75

in a _/5 scale

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6
Q

What is the transition peroid for a dairy cow and why is it important

A
  • 3 weeks before calving and 3 weeks after
  • Lots of physiologic and metabolic changes = high risk for disease
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7
Q

What is critical for a transitioning dairy cow

A
  • Dry matter intake critical
    o Good: >13 kg
    o Meh: 10-13 kg
    o Bad: <10 kg
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8
Q

What is the ideal BCS for dairy cows drying off, calving, and breeding

A

o Drying off = 3.25 – 3.75
o Calving = 3.25 – 3.75
o Breeding = 0 – 3.5

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9
Q

What are the goals for feeding a lactating cow

A

Goals
* Prevent BCS loss
* Maximize DMII and milk production
* Return to reproductive function

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10
Q

What are the energy requirements of a lactating cow

A
  • Maintenance
  • Growth (if in 1st lactation)
  • Milk production
  • Reproduction
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11
Q

What factors impact nutritional requirements for lactating cows

A
  • Parity (number of prior lactations)
  • Days in milk
  • Milk yield and composition
  • Cow wight
  • Activity/environment
  • Gestational phase
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12
Q

How should you feed a fresh cow

A

Early lactation
* Fresh cow (transition)
* Feed separately from main lactation herd

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13
Q

What are the nutritional requirements of a fresh cow? Why is it important

A
  • Nutritionally
    o High fibre/NDF
    o Low starch
    o Bypass rumen for amino acids and fat
    o Molasses
  • Should be getting pregnant after ~ 90 days in milk
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14
Q

What are 2 reasons why a cow isn’t getting pregnant

A
  • If not pregnant
    o Negative energy balance: delay first ovulation
    o Increased dietary crude protein: excess urea in plasma = change uterine environment
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15
Q

What are the requirements of a cow in late lactation? What are 2 things to consider when feeding

A

Late lactation
* Low nutrient demand
* Low milk yield

  • High DMI – recover BCS but don’t overcondition
  • No negative energy balance
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16
Q

Why is overconditioning dry cows a problem

A
  • Excess = reduced DMI near calving and higher risk of metabolic disorders
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17
Q

What is Negative energy balance and Low dietary fibre associated with in the transition period respectively

A
  • Negative energy balance associated with ketosis and fatty liver
  • Low dietary fibre = acidosis and displaced abomasum
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18
Q

What type of feed do you use for lactating cows

A
  • TMR: single ration for all lactating cows + avoids social distress and competition
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19
Q

How is concentrate and forage balanced in lactating cow TMR? Why

A

o Forage: high cellulose that facilitate rumination
 Ruminal pH = 6-7
 Acetate : Propionate (4 : 1)
 More = milk fat/acetate/fatty acids
 Less = milk volume

o Concentrate: starch, less rumination
 Ruminal pH = 5.5 - 6
 Acetate : Propionate (2 : 1)
 More = propionate/glucose/lactose/milk volume
 Less = milk fat

o Should have a ratio of 60 : 40 (forage : concentrate)

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20
Q

Compare structural and non structural carbs for lactating cows

A

o Structural: from rumination (acetate VFA), microbial protein and milk fat
 Particle size is important: minimum size to stimulate rumination
 NDF or ‘physically effective’ NDF (physical effectiveness based on particle size)

o Non-structural: propionate VFA, microbial protein, lactose, milk volume
 Via non-thermal processing: roll/crack/grind
finer ground is more digestible but higher risk of acidosis
* Increase surface area and break pericarp = make endosperm accessible

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21
Q

How do automated milking systems influence lactating cow diets

A
  • Automated Milking system:

o Partial mixed ration between milkings
o Concentrate when milking (grain)

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22
Q

How is protein given to dairy cows

A
  • Protein: Nitrogen
    o Low in diet – most from microbial protein synthesis
    o In diet: focus on bypass protein and amino acids (methionine and lysine) – plant based
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23
Q

How is lipid utilized in dairy cows? What is their max amount allowed in diet?

A
  • Lipid: not fermented
    o Max dietary = 7%
    o Can bypass rumen to allow utilization
24
Q

What is the law of minimum in the context of dairy nutrition

A

o Law of minimum: require all amino acids to make protein, rate limiting amino acids = methionine and lysine

25
When do dairy cows need fat supplementation the most
When they are fresh because they have a negative energy balance
26
Why is water important to dairy cows
* Water: affect DMI and milk production drink = (150L/d)
27
What are the 3 types of diets
Diet types * Formulated by a software * Mixed * Eaten
28
What herd parameters to evaluate when looking at dairy cow nutrition
Parameters * BCS * Fecal score * Milk components * Health events * Repro performance
29
What are the 3 parameters to evaluate when looking at dairy cow nutrition
* Dairy herd * Feed/feeding * Bunk management
30
How is BCS used to evaluate dairy nutrition
* BCS: 1/5 scale, shouldn’t decrease more than 1 score – overconditioning is worse than under
31
How is fecal score used to evaluate dairy nutrition
* Fecal score: 1/5 scale, reflect passage rate – fibre and water content o Lactating score = 3/5 (more grain) o Dry cow/heifer/calf = 4/5 (watery = 1, fast transit)
32
How are milk components (2 components) used to evaluate dairy nutrition
o Milk fat %: diet inadequacy + milk fat depression syndrome – high non-structural carbs and low fibre  Made from acetate o Milk urea nitrogen mg/dl: reflect protein nutrition
33
What are 3 main feed parameters to evaluate
Feed/Feeding Parameters * Quality * Particle size/mixing * Ingredient changes
34
What are 3 main bunk management factors to evaluat
Bunk Management * Distribution along the bunk * Bunking space – reduce competition * Frequency of push-ups and feeding (SID/BID – push up many times daily)
35
List 5 nutritional/metabolic disorders common in dairy cows
Ketosis Hypocalcaemia Displaced Abomasum Ruminal acidosis Bloat
36
What is ketosis? What causes it?
* Energy metabolism disorder – negative energy balance o Use triglycerides via lipolysis = make non-esterified fatty acids (NEFA) for krebs cycle  Lack of proprionate = no glucose = no krebs cycle function  NEFA made into beta-hydroxybutyrate (ketone bodies)  In liver * Hyperketonemia = excess long chain fatty acids o Will be positive feedback loop = negative energy balance cause anorexia = worsen negative energy balance
37
Compare type 1 and 2 ketosis
* Type 1: 2-4 weeks post partum o Increased milk production/energy demand – no association with fatty liver * Type 2: near parturition o Associated with fatty liver
38
What are the clinical signs of ketosis
* Clinically: reduced dry matter intake and milk production + lethargy o Behaviour: aggression/incoordinate/chewing on non-food
39
What are 4 ways to prevent ketosis
o Adequate nutrition in transition period o Avoid reduced dry matter intake and maximize postpartum  Use palatable feed/water/adequate bunk space  Control BCS o Smooth transition to lactation diet o Use additives
40
What are 3 types of additives to dairy cow feed? What do they do?
 Choline: fatty liver, limiting factor for VLDL fat export in liver  Proprionate precursors: propylene glycol, glycerol  Ionophores: monensin/lasalocid * Make pore in gram + bacteria = increase propionate > acetate production
41
What is hypocalcemia? What causes it?
* Calcium homeostasis failure * Excess demand for calcium postpartum and no PTH sensitization
42
What are the types of hypoCa? When does it occur
* Usually 2-3 days in milk o Transition period * Clinical form: 2-5% * Subuclinical form: 50% (especially older cows
43
How to prevent hypoCa? How does it work?
acidogenic diet o Promote bone mobilization o Negative dietary cation-anion difference: compensated metabolic acidosis  Ionized calcium displacing it from albumin = mobilize Ca earlier  Excess PTH secretion and sensitization + expression of PTH receptor on kidney  Fresh forage high in K = if on pasture and given DECAD diet it does not work * Only works for cows on TMR HOW o Add Cl/SO4 (no Na/K supplement) = imbalance epithelial cell = force HCO3 into GI lumen and retain H+ = acid
44
How are acidogenic diets monitored
o Monitor via urine pH – check 48h post new diet  Goal pH = 6.2 – 6.8  Bad/uncompensated metabolic acidosis = 5 – 5.5 (reduced DMI)
45
What is abomasal displacement
* Gas distension and hypomotility of abomasum – usually LDA
46
What are risk factors of abomasal displacement
* Higher risk in transition period and several weeks post – calving * Risk factors o Reduced DMI: feed availability/crowded bunks/poor TMR o Hypocalcaemia: reduce smooth muscle contractility o High grain diet for fresh cows: increase VFA in abomasum lowers contractility (reduce ruminal contractions)
47
How is abomasal displacement prevented
* Prevent o Avoid reduced DMI and maximize post partum o Smooth transition to lactation diet o Use additives
48
What is ruminal acidosis
* Acid production > absorption (due to excess fermentable carbs)
49
Compare the 2 types of ruminal acidosis
* Acute/Lactic: pH = <5 o Lactic acid accumulation o Less common – can be fatal * Subacute ruminal acidosis: pH = 5.2 – 6.2 o Chronic o Common in dairy o VFA accumulation: reduce DMI/cellulytic fermentation
50
What are 2 clinical consequences of subacute ruminal acidosis
o VFA accumulation: reduce DMI/cellulytic fermentation  Cause damage to rumen leading to liver abscess  Altered hemodynamics/histamine/endotoxin = laminitis
51
How is ruminal acidosis prevented
* Prevent o Gradual diet change – small increase in starch o Use same ingredients o Minimize peNDF in TMR o Give dietary buffers (sdium bicarb/limestone) or ionophores
52
What is bloat
* Abnormal distension of rumen
53
What are the 2 types of bloat
* Frothy/primary o Stable foam that traps gas and prevents eructation * Free gas/Secondary
54
What causes primary bloat
o Stable foam that traps gas and prevents eructation o High soluble protein diet = dairy cows on pasture (legumes/young green cereal crops)
55
How to prevent primary bloat
 Grazing management: avoid early stage grass  Use bloat safe forage: plants with tannins (bind soluble protein and inhibit microbial fermentation)  Inter-seeding legume/grass  Surfactant oils: add to water

VETM 465 Nutrition (10 decks)

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