Bovine Mastitis Flashcards Preview

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Flashcards in Bovine Mastitis Deck (143)
1

What should you monitor in the parlour?

Fore milking
Visual changes in udder/cow (Off food? Pyrexia? Depressed?)
Teat/udder feel
Cow response to palpation
Californian Mastitis test
In line detectors (filters, electrical conductivity)

2

What can you monitor when investigating mastitis?

In parlour monitoring (clinical signs, fore milking etc)
Clinical case records
SCC
Bulk tank bactoscan
Bacteriology (bulk tank/individual/high SCC)
Multiplex PCR

3

Why might a bulk tank bactoscan be high?

Poor housing cleanliness
Putting milk from clinical cases in bulk tank
Poor plant cleaning
High levels of mastitis on farm
Poor teat cleanliness

4

Why do we do individual cow cell counts?

Identifies high cell count cows in herd, chronically infected and stage of lactation

5

What does a SCC of >200,000 cells/ml indicate?

Infected quarter with major pathogen

6

What is the target % of clinical cases of mastitis?

<30% (UK average is actually 45-65%)

7

A bulk milk cell count over which value would put a farmer under threat of not collecting milk any longer?

>400,000

8

A cow will test positive on a California Mastitis Test if it has a SCC value of what?

>300,000 from any quarter

9

What does a Bactoscan tell you?

Actual count of bacterial numbers in milk

10

Who carries out a Bactoscan?
When?

Milk processor company
Measured weekly but can get daily

11

Give a treatment plan for chronic high cell count cows

Identify pathogen
1. Treat during lactation according to culture and sensitivity
2. Dry off and treat-better bacteriological cure rate
3. Cull chronically infected, older cows

12

Which treatment should you use for cows with chronic high cell counts if treating during lactation?

Extended courses of intra-mammary therapy for Staph aureus and Strep uberis eg cloxacillin for 6 days
Systemic eg tylosin, penethamate
Mini blitz-all high cell count cows together as a group and treat according to culture and sensitivity

13

Which treatment should you use for cows with chronic high cell counts if drying off and treating?

Dry cow intra-mammary antibiotic and systemic antibiotic eg tylosin

14

Milk exceeding which value for Bactoscan will be excluded from the supermarket supply?

50,000/ml, until under 50,000 for 3 months

15

What is included in a bulk tank bacteriology?

Total bacterial count
Cell count
LPC thermoduric count and pseudomonas
Coliform count
Total Staphylococcal count
Staph aureus
Identifies other pathogenic bacteria

16

Which cows should be sampled when doing individual cow bacteriology?

All clinical cases
High cell count cows

17

Give some possible problems with individual cow bacteriology

Contaminated samples
Some pathogens are only intermittently shed eg Staph aureus
May be no bacterial growth if cow has had antibiotics

18

How would you carry out a milk sample collection for individual cow bacteriology?

1. Wear gloves
2. Clean, disinfect and dry the teat
3. Discard 10-15ml of foremilk
4. Clean each teat end and orifice for 15-20 seconds with a cotton wool swab soaked in 70% alcohol (clean further ones before closer one)
5. Sample close teats then far away ones (avoid contamination)
6. Keep sample container horizontal
7. Teat-dip afterwards

19

How would you interpret finding more than 3 bacteria on an individual cow bacteriology?

Probably a contaminated sample
Repeat

20

How would you interpret finding no growth of bacteria on an individual cow bacteriology?

Cow is intermittently shedding or has had antibiotics
Repeat

21

How would you interpret finding more than 1 major pathogen on an individual cow bacteriology?

Mixed aetiology

22

How would you interpret finding a major pathogen and a minor pathogen on an individual cow bacteriology?

The major pathogen is the causal agent

23

How is milk removed from the teat during milking?

Negative pressure is created outside the teat by applying a vacuum (42-48kpa) controlled by a regulator
Vacuum is applied intermittently (continuous -> would stop circulation in teat)

24

Where does the long milk tube of the cluster unit go?

To the bulk tank

25

How does the milking machine contribute to mastitis?

1) Damages the teats and teat ends
2) Acts as a vector for transfer of infection

26

How may the milking machine cause teat damage?

-Worn/hard/faulty liners
-Inadequate rest phase in pulsators/pulsators set too fast (poor teat circulation)
-Excess vacuum
-Over-milking
-Inadequate emolient in post-milking teat dip
-Poor pre-milking teat preparation (slow milk let down)

27

Which condition of the teat can occur due to damage from the milking machine?

Teat end sphincter hyperkeratosis

28

How would you recognise damaged teats?

Blue, oedematous, chapped or petechiations

29

How can milking machines transfer infections?

-Contamination of liners-transfer of pathogens in teat skin
-Wet miling (milk flushed up into teat canal carrying pathogens with it)
-Blocked air bleed
-Fluctuating/inadequate vacuum

30

Give a problem with air bleeds getting blocked on cluster units

Can cause flooding of the claw piece -> teat end impactions

31

How many pulsations should occur per minute in a milking cluster unit?

60

32

Why may a cow kick/paddle when being milked?

-Over-milking
-Faulty vacuum/pulsators
-Excess vacuum
-Hard liners

33

How many cows should you score when teat scoring?

20% of cows in each pen

34

What are the 4 scores for teat scoring?

1= normal
2= smooth (best)
3= rough
4= very rough

35

What is a problem with over-shedding of keratin on teat ends?

Bacteria can stick to keratin and cause infection

36

Do the front or back 2 teats produce the most milk?

Back 2 (hence the back 2 clusters are weighted)

37

What should be carried out before milking?

Fore-milking
Teat disinfection (must dry after washing)

38

What should be carried out after milking?

Post-milking teat disinfection
Loafing time (let cows stand to allow time for teat ends to close)

39

Why should we carry out fore-milking?

-Legal requirement
-Allows early detection of mastitis
-Stimulates milk let down reflex

40

Which hormone stimulates milk let down?
When is it released?

Oxytocin
Released in reponse to physical stimulation of teat

41

Give some common disinfectants used to clean teats before milking

Chlorohexidine (non-irritant, 0.35-0.5%)
Iodophors (0.1-0.5%)
Chlorine dioxide (active in presence of faeces)

42

Why should we clean teats post-milking?

To remove bacteria transferred to teats during milking (particularly contagious pathogens)

43

Why should cows have loafing time after milking?

Allows closure of the teat sphincter post-milking and prevents environmental infections

44

How much loafing time should cows have?

30 mins

45

Give a potential problem with loafing times

May exacerbate lameness

46

How can we prevent the spread of mastitis in the parlour?

-Milking order (milk clinical cases last)
-Cluster disinfection

47

Give the order cows should be milked in

1) Heifers
2) Fresh calvers
3) High yielders
4) Low yielders
5) High cell count cows
6) Mastitic cows

48

Describe a parlour wash routine

Clean milk out and remove bacteria deposited
Cold rinse (once daily)
Hot wash (once daily)
Rinse with hypochlorite
Acid and alkali washes (acid gets rid of calcium and protein, alkaliturns fat into soap and rinses out)

49

How hot does a parlour wash have to be?

85-90oC

50

What should you listen for in a parlour?

Liners slipping off
Vacuum regulator (hissing sound if working)

51

How should you manage high cell count/mastitic cows in the parlour?

Use a separate cluster and disinfect between cows
Back flush the cluster with water and disinfectant between cows
Hypochlorite solution
Per-acetic acid

52

Describe the cure rate for mastitis caused by Staph aureus

Low (20-60%) as it exists intra-cellularly so can be recurrent

53

What kind of antibiotics should be used to treat Staph aureus?

Systemic (as it exists intra-cellularly)

54

What kind of pathogen is Staph aureus (ie contagious or environmental)?

Contagious

55

Is Staph aureus gram +ve or -ve?

Gram +ve cocci

56

How would you identify Staph aureus bacteriologically?

Forms cream-yellow colonies and is haemolytic on blood agar

57

Is Trueperella pyogenes gram +ve or -ve?

Gram +ve rods

58

What kind of pathogen is Trueperella pyogenes (ie contagious or environmental)?

Environmental

59

How would you identify Trueperella pyogenes bacteriologically?

Small haemolytic colonies on blood agar

60

How would you identify Strep uberis bacteriologically?

-Small alpha haemolytic colonies on blood agar
-Edwards plate: aesculin hydrolysis -> plate turns black

61

What kind of pathogen is Strep uberis (ie contagious or environmental)?

Both

62

Is Strep uberis gram +ve or -ve?

Gram +ve cocci in chains

63

Is E.coli gram +ve or -ve?

Gram -ve, short stumpy rods

64

What kind of pathogen is E.coli (ie contagious or environmental)?

Environmental

65

How would you identify E.coli bacteriologically?

EMB agar: metallic green sheen to colonies

66

How would you identify Klebsiella bacteriologically?

Large mucoid colonies

67

What kind of pathogen is Klebsiella (ie contagious or environmental)?

Environmental

68

Is Klebsiella gram +ve or -ve?

Gram -ve rods

69

Is Pseudomonas gram +ve or -ve?

Gram -ve, slender long rods, medium-sized

70

What is the prognosis like for Pseudomonas?

Poor as typically very resistant

71

What kind of pathogen is Pseudomonas (ie contagious or environmental)?

Environmental

72

How would you identify Pseudomonas bacteriologically?

Green pigmentation on nutrient agar

73

How long is the dry period?

Typically 60 days but can be shortened to 42-45 days

74

How would you interpret a California Mastitis Test?

If milk becomes clumpy/gloopy -> positive result

75

When should you replace a liner from a cluster?

After 2500 milkings

76

Why do we use dry cow therapy?

To clear persistent infections (contagious pathogens eg Staph aureus) and protect against new ones (environmentl pathogens eg E.coli)

77

Which pathogens cause summer mastitis?

Arcanobacter/trueperella pyogenes (necrosis)
Strep dysgalactiae (1o infection?)
Peptococcus indolicus (foul smell)

78

What are the main antibiotics in UBRO red?

Penecillin as procaine salt 300mg, + Framycetin (Neomycin) + Penethamate (Penecillin ester)

79

Give some disadvantages of dry cow therapy

-Lower cell count (more prone to acute mastitis?)
-Hygiene during application -> new infections
-Product must have wide spectrum of activity
-Need to treat 100% of quarters to protect 15% of herd
-Antibiotic resistance
-Expensive
-Consumer pressure?

80

When should you use teat sealants?

In cows with cell counts below 200,000 and no case of mastitis in previous lactation

81

What are the main ingredients of teat sealants?

4g of suspension containing 65% bismuth subnitrate

82

How do teat sealants work?

Remain as a paste within the base of the teat cistern and teat canal until stripped out at calving

83

What is Arlagarden?

Vet must complete a form which states which dry therapy is being used on the farm and why, and some measures towards a more selective approach to dry cow therapy

84

Cows not treated with a sealant are how many times more likely to get mastitis?

50% more likely

85

With selective dry cow therapy, which cows should you give teat sealants to?

Cows: <150,000 cell/ml
1st lactation heifers: <125,000 cell/ml
Must all have no clinical cases of mastitis in this lactation

86

What should you do before inserting an intra-mammary tube (antibiotic)?

HYGIENE!!!
Do after milking and cleaning of parlour
Clean gloves
Pre-dip and allow kill time of 30s+
Loads of surgical spirit and cotton wool
Clean teat end until no more comes off
Repeat

87

Which antibiotics are typically in intra-mammary tubes?

Cloxacillin +/- ampicillin
(Aim is to target Staphs primarily then broaden out)

88

Give some problems with mis-judging calving dates when using intra-mammary antibiotic tubes

If the product has too short a duration: risk of re-infection
If the product has too long a duration: will have to discard milk if calf is born whilst cow is still being treated

89

What is the average post-calving milk withhold of intra-mammary tubes?

Used to be 96hrs, but can now sell milk straight away after removing sealant

90

What is the average meat withold time of intra-mammary tubes?

10-30 days (most are 28 days)

91

What is a delvotest?

Tests milk for all antibiotic residues

92

How could you test milk for antibiotic residues?

Delvotest tests for residues of all/most antibiotics
Or can do a quick dip test for beta lactams

93

What is Tilmicosin licensed for?

Staph aureus in sheep not cattle

94

Give some other treatments you could use at drying off

Tylosin
Other long-acting macrolides:
-Tulathromycin (Draxxin)
-Gamithromycin (Zactran)
-Tildipirosin (Zuprevo)
(last 3 not licensed for milking cows)

95

Why might you not need to treat all mastitis cases?

-Some may be due to yeast
-Some will self-cure
-Some are culture negative
-Some farms don't treat mild gram-ve infections during lactations

96

Why may a mastitis treatment fail?

-Antibiotic resistance
-Bacterial dormancy (ie duration of tx isn't long enough)
-L-forms are resistant to beta lactams as don't have a cell wall
-Biofilms
-Reduced host response (steroids, stress)
-Reduced phagocytosis
-Pharmacokinetic limitations (eg binding of AB to milk/serum protein, intracellular parasitism, diffusion barriers due to eg oedema)
-Re-infections

97

Why may antibiotics not reach the site of infection in adequate concentrations?

-Too low a dose
-Too long a dose interval
-Too short a treatment period

98

Is milk acidic or alkaline?

Acidic

99

How can mastitis affect the blood/milk barrier?

Can cause it to break down

100

Which antibiotics are best for treating E.coli mastitis?

Tetracyclines
Potentiated sulphonamides (better penetration)

101

Why would MRSA be an issue in dairy cows?

Cross-infection between humans and cattle

102

Which antibiotic is good against gram -ve bacteria?

Neomycin

103

Are all streps and staphs gram +ve or -ve?

Gram +ve

104

Is lincomycin good for treating gram +ve or -ve bacteria?

Gram +ve

105

Give an example of a broad spectrum combination for treating gram +ve and -ve bacteria

Lincomycin (gram +ve) with neomycin (gram -ve)

106

What is 'pusle therapy'?

Treatment with ABs by treating then witholding then treating etc

107

What is 'blitz therapy?'

Treatment of whole herd with ABs (Strep agalactiae only)

108

Blitz therapy can only be used with which bacteria?

Strep agalactiae

109

What is the typical therapeutic strategy for ABs during lactation?

12 hr intervals for 3 consecutive milkings

110

Do intra-mammary or systemic ABs result in a quicker return to milk production and more milk production?

Systemic

111

What is 'Startvac'?

Vaccine for mastitis (against E.coli, Staph areus and coliforms; hinders the production of biofilm)

112

When is Startvac given?

Day 97 post-calving, 10 days pre-calving, and 45 days pre-calving

113

How long does Startvac protect for?

Up to 130 days post-calving

114

How could you tell that a cow is painful?

Increased sensitivity to touch, hyperalgesia, increased kicking, increased HR and RR, increased rectal temp

115

Give some NSAIDs you can use in cattle

Flunixin meglumine
Ketoprofen
Tolfenamic acid
Meloxicam
Carprofen
Aspirin

116

How would you treat the following case:
Young cow, first case of mastitis this lactation, high SCC previous month

Intra-mammary and systemic ABs

117

How would you treat the following case:
End of lactation, high SCC

Dry off and treat with dry cow therapy +/- injectable AB

118

How would you treat the following case:
Old cow, 3rd case this lactation, chronic high SCC

Cull

119

How would you treat the following case:
Young cow, first case, low SCC previous month

No treatment- watchful waiting

120

What should you do to every mastitis case before treating?

Sample it

121

What does 'ADF' stand for?

Automated dipping and flushing of cluster

122

What is Velactis?

New product: macrolide, dopamine receptor agonist -> inhibits prolactin
An aid to drying off as reduces milk production -> reduced milk leakage at drying off -> reduced risk of intramammary infections

123

What is Pegbovigrastim?

New product: restores normal neutrophil function during the peri-parturient period -> fewer cases of clinical mastitis

124

What is the difference between clinical and sub-clinical mastitis?

Clinical: visible grossly; changes in milk/udder/cow

Subclinical: infection present but no visible clinical signs. Changes in SCC, milk quality and yield

125

Give the possible consequences of a mastitis infection

-Cow clears the infection and returns to normal milk production
-Doesn't clear the infection and develops chronically-persistent bacterial infections -> spreads within herd
-Permanent damage to udder tissue and reduced milk yield
-Death from toxaemia or PTS

126

How does the innate immune response work?

WBCs -> activate acquired immune response -> humoral and cellular response (B and T lymphocytes, Abs)

127

How is the teat skin designed to fight bacteria?
How can it be compromised?

Stratified squamous epithelium with bacteriostatic fatty acids (to prevent colonisation of bacteria)
Can be compromised by bruising, chapping, trauma, teat lesions, milking machine (eg vacuum)

128

How often should a milking machine be serviced?

Every 12 months

129

How long does it take the teat sphincter muscle to close?

20-30 mins

130

How does the teat canal stop bacteria entering the udder?

Teat sphincter muscle acts as a barrier
Keratin lining traps bacteria and is continuously sloughing
Keratin plug forms over teat when cow is dried off

131

What % of cows form an effective seal from the keratin plus at drying off?

50%

132

What make up the innate immune response inside the udder?

Resident leukocytes (macrophages, neutrophils, T lymphocytes)
Lactoperoxidase (bacteriostatic)
Lysozyme (bacteriocidal)
Lactoferrin (inhibits growth of bacteria requiring iron eg E.coli)
Complement (opsonisation of bacteria; attracts phagocytes)

133

Which antibodies to B lymphocytes produce initially and after repeated exposure to bacteria?

Initially: IgG1, IgM
After repeated exposure: IgG2 ('vaccination')

134

Which antibodies are most important when dealing with bacteria in the udder?

IgG2

135

Which antibodies function in the udder? What do they do?

IgM: fixates complement for opsonisation of pathogens, agglutination of bacteria, neutralises toxins
IgA: agglutination of bacteria, neutralises toxins
IgG1: opsonisation of bacteria

136

Give some factors that affect mammary gland immunity

Genetics
Nutrition
Stage of lactation
Vaccination
Stress?

137

Cows in which period are more likely to acquire new mastitis infections?

Early and late dry period (although clinical disease is usually seen in the first 6 weeks after calving)

138

Why is WBC function reduced in the dry period and post-calving?

Early dry period: neutrophils are present but full of fat and cellular debris -> impaired function

Peri-parturient period:
-Increasing levels of IgG1 may interfere with neutrophil function
-Reduced neutrophil recruitment and phagocytic ability
-Macrophages have reduced phagocytic function

139

How does nutrition affect mastitis?

-Negative energy balance -> impaired activity and lower numbers of leucocytes
-Vit E and selenium deficiency -> slow migration and weaker activity of leucocytes
-SARA: reduced appetite -> reduced DMI -> NEB. Diarrhoea
-Hypocalcaemia -> weakened teat sphincter mechanism

140

What is the mastitis vaccine and what does it protect against?

Startvac
Protects against Staph aureus, coliforms, and coagulase-negative Staphylococcus
Reduces incidence of sub-clinical mastitis and severity, and incidence of clinical mastitis

141

Are Strep agalactiae and dysgalactiae contagious or environmental?

Contagious

142

If a cow develops mastitis in the first few months of lactation, what does this tell us about the infection?

It was likely picked up during the dry period

143

What can happen if teat sealants are not removed properly before a cow's first milking after the dry period?

'Blackspot' in cheese