5 Milking Management 1 Flashcards

1
Q

Explain the physiology behind milk ejection

A

Mechanical stimulation of teats leads to oxytocin release from posterior pituitary
Oxytocin reaches the mammary gland via blood circulation, binds to receptors of myoepithelial cells
Myoepithelial cells contract, milk evacuation from mammary gland

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2
Q

What is epinephrines role in milk ejection

A

Prevents oxytocin from binding its receptors when cow is excited, nervous, fearful

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3
Q

How does milk evacuate the mammary gland

A

Vacuum pressure (calves, milking machines) or mechanical forces (hand-milking)

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4
Q

Four basic steps of milking routine

A
  1. Pre-milking teat disinfection
  2. Fore-strip
  3. Machine attachment/detachment
  4. Post-milking disinfection
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5
Q

Describe the pre-milking teat disinfection

A

Wear gloves or disinfect hands
Kills bacteria on teat skin surface
Contact time needed: 20-30 seconds
Pay close attention to teat ends - where the milk comes out

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6
Q

Describe the fore-strip process

A

Eliminate bacteria in the ends of all four teats
Helps detect mastitis (abnormal milk in one teat)
Strongest stimulus for milk let-down; allows natural milk ejection process

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7
Q

Describe attaching the milking unit

A

Attach within 60-90 seconds after stimulation
Minimal air admission during claw attachment
Adjust milking cluster so weight is evenly distributed, aligned so teats are not twisted and liners don’t squawk

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8
Q

Slides 17-19

A

Prep vs no prep & oxytocin

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9
Q

What is the ‘ideal milking routine’

A

Udder prep: 10-20 sec/cow
Attachment delay: 40-70 sec/cow
Total prep-lag time: 60-90 sec/cow

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10
Q

How do you assess completeness of milking?

A

Using residual milk
250-500ml = ideal

> 500 ml = under milking
<250 ml = over milking

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11
Q

Describe post-milking disinfection

A

Full teat coverage for each teat
Spray may not adequately cover entire teat
Dipping cups use less disinfectant

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12
Q

Overarching goal for a milking routine

A

Every cow should be milking exactly the same at every milking for her entire lactation
Consistent routine! Cows are creatures of habit

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13
Q

Good milking management will… (3)

A
  • increase milk production and udder health
  • increase labour efficiency
  • decrease new intra-mammary infections
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14
Q

Mastitis definition

A

Inflammation, infection or trauma of the breast or mammary gland

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15
Q

Causes of mastitis

A

99% are bacterial infections
Rarely: algae, yeast
Very rarely: viral

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16
Q

Symptoms of mastitis

A

Inflammation = gross swelling, redness, heat, pain
Loss of function (yield and composition)

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17
Q

Clinical mastitis signs

A

Visible clots (leucocytes), swelling & redness, serum/blood in milk, pain, high SCC and LS< milk loss

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18
Q

How often should clinical mastitis occur in well managed herds?

A

~1% of cows

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19
Q

Subclinical mastitis signs

A

Normal appearing milk
Elevated SCC (>200,000)
Elevated LS (>4)
Milk loss

May affect large percent of herd

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20
Q

What are the contagious mastitis pathogens?

A
  • Streptococcus agalactiae
  • Staphylococcus aureus
  • Mycoplasma bovis
  • Prototheca
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21
Q

What are the environmental mastitis pathogens

A
  • Strep non-ags (uberis, dysgalactiae)
  • Coliforms
  • Yeasts, nocardia, pseudomonas
22
Q

Describe Strep agalactiae

A

Gram +
Lives on membrane surfaces
Easily killed with teat dips, penicillin
Spread through contaminated milk
Easily controlled via routine teat dipping and dry cow treatment

23
Q

Describe Staph aureus

A

Gram +
Produces penicillinase; resists most antibiotics
Highly infectious; chronic; no effective cure

24
Q

Describe mycoplasma bovis

A

Naturally in respiratory tract of cattle
Multiple quarters can be infected, reducing milk yield drastically
Antibiotic treatment not effective

25
Q

Describe prototheca

A

Caused by algae
Considered both contagious and environmental pathogen
Antibiotic treatment not effective

26
Q

Describe Strep uberis, Strep dysgalactiae

A

Gram +
Produces penicillinase
Resistant to some antibiotics
Sources: hair, flies

27
Q

Describe coliforms. E.g.

A

(E. coli, Klebsiella, Enterobacter)
Gram -
Sources: manure, bedding, contaminated water
Toxins released by lipopolysaccharides in membrane causes severe systemic reaction

28
Q

What pathogens can be identified using Mastitis 4 DNATest

A

Strep agalactiae, Staph aureus, Mycoplasma bovis, Prototheca

29
Q

Slide 39, 41

A

Mastitis $$$ losses

30
Q

How does Mastitis affect milk?

A

Lower milk yield, cheese yield, Ca & P content, casein content, lactose content, fat content

31
Q

Mastitis may cause an increase of what in the milk?

A

Some minerals (Sodium chloride

32
Q

What is SCC? LS?

A

Somatic cell count (thousands/ml)
Linear score for SCC

33
Q

When do you start to see minor reductions in milk production with SCC?

A

SCC 71-140,000
LS 3

34
Q

At what SCC does it become illegal to ship milk?

A

283-565,000
LS 5

35
Q

Slide 42** & 43

A

SCC and LS

36
Q

What are SCC management goals for 1st lactation and the herd

A

1st lactation want an average LS around 2 (80% LS 0-3)

Herd you want an average LS of 2.8 (65% LS 0-3, 30% LS 4-5)

37
Q

What provides natural protection from mastitis

A

Udder conformation (strong support by median suspensory ligament, teat placement)

Teat sphincter & Furstenburg’s rosette (prevent milk leakage, keratin)

38
Q

How does the immune system respond to mastitis infections

A

Chemotaxic leucocyte response to antigens
Phagocytosis of antigens (bacteria)
Polymorphonuclear leucocytes (PMN)

39
Q

What is PMN invasion

A

Polymorphonuclear leucocytes
Pathogen colonization of alveolar tissue
PMN infiltration into alveoli
Inflammation

40
Q

What is the National Mastitis Council (NMC) five-point program for mastitis control

A
  1. Functional milking equipment
  2. Dip all teats after milking
  3. Treat clinical cases with effective antibiotic
  4. Dry cow treatment
  5. Cull chronic mastitis cows
41
Q

When will you see effective results with antibiotic treatment of mastitis

A

Works well for first treatment in young animals
Older animals with chronic mastitis = less effective results

42
Q

What is dry cow treatment

A

Treat all quarters of cows at dry-off
Culture to know pathogens and use effective anitbiotics

43
Q

When do most new mastitis infections occur

A

At calving or early postpartum or at dry-off

44
Q

Advantages and disadvantage of dry treatment

A

Adv:
- higher legal dose of antibiotic (cows not milked)
- antibiotic remains in udder longer
- better tissue contact (less dilution)
- no milk discard

Dis: antimicrobial resistance?

45
Q

Why do we cull chronic mastitis cows?

A
  • some mastitis is incurable (esp Staph aureus)
  • infected cows are potential reservoirs of infectious organisms
46
Q

Ways of detecting clinical mastitis (3)

A
  • strip cup
  • other signs of inflammation (pain, redness, swelling, heat)
  • fever
47
Q

What is a strip cup good for

A
  • detecting abnormal milk
  • identification of infected quarter(s)
  • visible changes in milk (clots, clumps, watery)
48
Q

How do we detect subclinical mastitis using SCC

A

Somatic cell counts (SCC)
- uses optical density to detect somatic cells
- majority of cells are PMN leucocytes
- indicates cellular response to infection

49
Q

Second way of detecting subclinical mastitis

A

California mastitis test
- detergent coagulates cellular DNA
- more coagulation = more SCC
- rapid cow-side test: able to identify specific quarters

50
Q

Third way of detecting subclinical mastitis

A

Electrical conductivity
- infected milk is high in Na and Cl content
- salts increase electrical conductivity