MODULE 21 - B > PATHOLOGY - Mastitis > Flashcards

PATHOLOGY - Mastitis Flashcards

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1
Q

What is mastitis?

A

Mastitis is inflammation of the udder

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2
Q

Why is mastitis of such concern within the dairy industry?

A
  1. Mastitis is a welfare issue as clinical mastitis is very painful
  2. Mastitis causes production and economic losses
  3. Mastitis increases somatic cell count (SCC) which reduces milk quality
  4. Mastitis increases antibiotic use which contributes to antimicrobial resistance
  5. Mastitis can result in poor consumer perception
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3
Q

What are the production and economic impacts of mastitis?

A
  1. Mastitis causes damage to the mammary tissue which reduces milk production, with clinical mastitis causing cows to lose 15% or their total production
  2. Mastitis increases somatic cell count (SCC). An increase beyond certain levels will result in financial penalisation of the farmer in accordance with supermarket contracts
  3. Milk discard costs
  4. Treatments costs
  5. Early, unwanted culling of cows
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4
Q

What is the difference between clinical and subclinical mastitis?

A

Clinical mastitis presents with visible changes in the milk and there may be visible changes of the udder. Whereas subclinical mastitis there will be no visible changes in the milk or udder

When answering exam questions about the difference between clinical and subclinical mastitis, specify the changes you would see in the milk and udder

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5
Q

What is mild clinical mastitis?

A

Mild clinical mastitis is where there are visible changes in the milk

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6
Q

What is moderate clinical mastitis?

A

Moderate clinical mastitis is where there are visible changes in the milk and the udder

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7
Q

What is severe clinical mastitis?

A

Severe clinical mastitis is where there are visible changes in the milk, udder, and signs of systemic disease

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8
Q

Which visible changes can you see in the milk in a cow with clinical mastitis?

A

Watery
Thickened
Discoloured
Blood
Pus
Flakes
Clots

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9
Q

Which visible changes can you see in the udder in a cow with clinical mastitis?

A

Swollen
Firm
Red
Hot
Painful
Reduced size of the quarter

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10
Q

Which systemic disease signs can you see in a cow with severe clinical mastitis?

A

Pyrexia
Dehydration
Weakness
Inappetence

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11
Q

Define a ‘clinical case’ of mastitis

A

A clinical case of masitis refers to one infected quarter. If the same cow has two infected quarters, this would be two clinical cases of mastitis

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12
Q

Define a ‘new clinical case’ of mastitis

A

A new clinical case of mastitis refers to mastitis that has arisen 8 or more days since the previous case in the same cow

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13
Q

Define a ‘recurrent clinical case’ of mastitis

A

A recurrent clinical case of mastitis is when less than 7 days have passed and there is another case of mastitis within the same cow

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14
Q

Define chronic clinical mastitis

A

Chronic clinical mastitis refers to long-term, persistent, recurring mastitis

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15
Q

What are somatic cells?

A

Macrophages
Lymphocytes
Neutrophils
Epithelial cells

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16
Q

Define a ‘new subclinical case’ of mastitis

A

A new subclinical case of mastitis refers to an increase in somatic cell count (SCC) in a milk sample to over 200 000 cells/ml (in cows) and 150 000 cells/ml (in heifers)

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17
Q

Define a chronic subclinical case of masitis

A

Chronic subclinical mastitis refers to a cow with 3 or more consecutive milk records with over 200 000 cells/ml on their somatic cell count (SCC)

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18
Q

How can you detect subclinical mastitis?

A

California mastitis test (CMT)
Herd test/milk test
Conductivity meter

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19
Q

What is the California mastitis test (CMT)?

A

The California mastitis test (CMT) is a crude, cow-side test which can estimate the somatic cell count (SCC) in a milk sample

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20
Q

How do you carry out a California Mastitis Test (CMT)?

A
  1. Directly squirt milk from each quarter into the appropriate section of the paddle
  2. Look at the milk for any obvious gross changes in the milk
  3. Tilt the paddle to a 45° angle pour off excess milk so there is an equal amount of milk in each tray
  4. Add equal parts of the reagant to the milk, and mix them by swirling the paddle for 15-20 seconds
  5. Watch for changes in the solution. If there are no changes, the milk is fine, if the solution forms a thick slime, this suggests a high somatic cell cound (SCC)
  6. If the results are positive, mark the cow with spray to identify the positive quarter
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21
Q

What is the grading system for the California Mastitis Test (CMT)?

A

0 = no slime
1 = little slime
2 = moderate slime
3 = heavy slime

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22
Q

What is a herd test/milk test?

A

A herd test/milk test is a voluntary service that farmers pay for where people will come out and take milk samples and send these off to the laboratory to get an accurate somatic cell count (SCC). This is the most accurate way to determine the somatic cell count (SCC) within a sample

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23
Q

Why is a conductivity meter not recommended for the detection of subclinical mastitis?

A

Conductivity meters have low sensitivity and specificity for the detection of subclinical mastitis

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24
Q

In what types of milk samples can somatic cell count (SCC) be measured?

A

Somatic cell count (SCC) can be measured for both individual and bulk tank milk samples

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25
What is indicated by a sudden increase in somatic cell count (SCC) by 100 000 cells/ml or more in the bulk tank milk sample?
A sudden increase in somatic cell count (SCC) by 100,000 cells/mL or more in a bulk tank milk sample typically indicates a clinical mastitis cow has accidentally been put into the supply, indicated by this sharp increase in SCC
26
How do mastitis infections commonly spread through cows?
Infection can occur through haematogenous spread of the pathogen, however this is less common. Most mastitis pathogens enter the udder through the teat canal
27
What are the cow's innate immune defences agaisnt mastitis?
Teat skin Teat sphincter Keratin Innate immune cells
28
How does the teat skin provide innate immunity to mastitis?
The teat skin acts as a physical barrier against pathogens, and has a protective mantle of fatty acids which slow the growth of bacterial pathogens
29
How does the teat sphincter provide innate immunity to mastitis?
The teat sphincter is a smooth muscle which tightly closes between milkings to prevent pathogens entering through the teat canal
30
Why is the 30 minutes after milking a risk factor for mastitis?
The 30 minutes after milking is a risk factor for mastitis as it takes approximately 30 minutes for the teat sphincter to close after milking, increasing the risk of pathogens entering via the teat canal
31
How can you reduce the risk of mastitis after milking?
Post-dipping solutions should work for 30 minutes post milking, allowing the teat sphincter time to close, reducing the risk of mastitis
32
How does keratin provide innate immunity to mastitis?
Keratin is a fibrous protein with a lipid component which lines the teat canal and has bacteriostatic activity
33
What is the significance of the keratin plug?
The keratin plug forms at the teat sphincter at dry-off as an additional form of protection agaisnt pathogens. However, it has been found that it can take cows within the herd a long time to form this keratin plug, especially high performing cows - which increases their risk of mastitis during the dry-off period
34
What has been shown to increase the chances of cows forming keratin plugs at the beginning of dry-off?
Dry cow therapy has been shown to increase the chances of cows forming keratin plugs at the beginning of dry-off by 30%
35
What can impair the innate teat defences against mastitis?
Abrasions Cracks Chapping Viral infections Overmilking/milking machine malfunction
36
What damage can be caused to the teat by overmilking/milking machine malfunction?
Hyperkeratosis Oedema
37
What are the immunosuppressive related risk factors for mastitis?
Dry-off Calving Nutritional deficiencies Transition cow diseases Individual variation in immune system Concurrent disease | These factors can immunosuppression and/or stress
38
How do you manage subclinical mastitis?
Subclinical mastitis does not typically require antibiotic treatments unless you culture bacteria from a milk sample
39
How do you manage clinical mastitis?
Intramammary antibiotics NSAIDs Milking out the affected quarter(s) Fluid therapy (if indicated) Systemic antibiotics (if indicated)
40
Why should you milk out the affected quarter(s) when treating mastitis?
You should milk out the affected quarter(s) when treating mastitis as this flushes out the bacteria and debris to help to clear the infection
41
What are you aiming for when you're treating clinical mastitis?
When treating clinical mastitis, you are aiming for a clinical cure which refers to there being no clinical signs of mastitis after treatment
42
How do you choose an appropriate antibiotic to treat clinical mastitis?
Choose an antibiotic based on the historic milk samples from the farm which could indicate the causative pathogen, and determine the resistance profile of the farm based on historic culture and sensitivity results
43
What are the three factors that are assessed to assess milk quality?
Milk hygiene Inherent milk quality Adulteration contamination
44
What is used to determine milk hygiene?
Total bacteria count (TBC) Bactoscan Somatic cell count (SCC)
45
What are the main sources of bacterial contamination of milk?
Dirty teats Mastitic milk Pool cleaning/disinfection of the milk machine Pool cleaning/disinfection of the bulk tank Poor milk refrigeration
46
What are the limitations of total bacteria counts (TBC) and bactoscans to assess milk hygiene?
Total bacteria counts (TBC) and bactoscans only provide a retrospective evaluation of milk hygiene
47
What are the limitations of somatic cell counts (SCC) to assess milk hygiene?
Somatic cell counts (SCC) only provide a retrospective evaluation of milk hygiene, have physiological variations between cows, and there is a dilutional effect so farmers with larger herds could potentially keep cows with high SCC within the supply as the dilutional effect of the rest of the herd will mask it
48
Why should freshly calved cows be kept out of supply for 8 milkings post calving?
Freshly calved cows be kept out of supply for 8 milkings post calving as their body will be under stress and she will be immunocompromised so she will have a high individual somatic cell count (SCC) which would increase the bulk tank somatic cell count (SCC)
49
Which factors are measured to assess inherent milk quality?
Milk protein percentage Milk butterfat percentage
50
What is the main protein found in milk?
Caseins
51
What is the normal protein percentage in milk?
3.2%
52
What is indicated by a decrease in milk protein percentage?
A decrease in milk protein percentage following an increase in milk butterfat percentage indicates an energy deficit
53
What is the normal butterfat percentage in milk?
4%
54
What is indicated by an increase in milk butterfat percentage?
An increase in milk butterfat percentage could be due to breed variation - i.e. Jersey cows have a high buttermilk percentage - or due to an energy deficit
55
How does mastitis alter the inherent milk quality?
Mastitis reduces the caseins, lactose, butterfat, and calcium, which overall reduces the protein and butterfat percentages - reducing milk quality
56
Which factors are measured to assess for adulteration contamination of milk?
Water content Residues (especially antimicrobial residues)
57
Why is water content assessed when assessing milk for adulteration contamination?
In the UK, farmers are paid for their milk by the litre, so it is important to assess if water has been added to the milk to increase the litres
58
What should be done if dairy cows are being treated with antibiotics?
Dairy cows being treated with antibiotics should be marked with red spray paint and tail tape to prevent them being put into the milk supply - as this could result in antimicrobial residues being present in the milk
59
What are the required standards for milk at the time of collection?
- Total bacteria count (TBC) less than 100 000 CFU/ml - Somatic cell count (SCC) less than 400 000 cells/ml - Absent antimicrobial or other residues - Temperature at point of collection less than 6℃ - Tracebility of the milk to the farm of production - Water used to clean the milking equipment should be tested annually
60
What are the potential sources of infection for mastitis?
Human to animal transmission Iatrogenic mastitis Contagious mastitis Environmental mastitis
61
How can humans transmit pathogens and cause mastitis in cows?
Contaminated hands or gloves Clothing or equipment Direct shedding of human pathogens Poor milk hygiene protocols
62
What can cause iatrogenic mastitis?
Improper intramammary treatment Incorrect use of teat sealants
63
What is contagious mastitis?
Contagious mastitis is where pathogens are transmitted from cow to cow usually via the milking machine or the milkers (human hands)
64
What is environmental mastitis?
Environmental mastitis is where pathogens are acquired from the cow's environment. This infection typically occurs when environmental bacteria enter via the teat canal or via teat skin abrasions or damage
65
What are the main contagious mastitis pathogens?
Staphylococcus aureus Streptococcus agalactiae Mycoplasma spp. ## Footnote Be aware that contagious and environmental pathogens often overlap and are more nuanced than this
66
What are the main environmental mastitis pathogens?
Streptococcus dysgalactiae Streptococcus uberis Coagulase negative staphylococci (CNS) E. coli Pseudomonas spp. Trueperella pyogenes Yeast ## Footnote Be aware that contagious and environmental pathogens over overlap and are more nuanced than this
67
What is the difference between major and minor pathogens?
Major pathogens cause serious immune reactions with an increase in somatic cell count (SCC), decreased milk production and quality and visible changes in milk ± visible changes in the udder and systemic disease. Whereas minor pathogens cause a minor immune response, with no or a slight increase in somatic cell count (SCC) and little change in production or milk quality, and are unlikley to cause clinical signs
68
What are some of the major mastitis pathogens?
Staphylococcus aureus Streptococcus agalactiae Streptococcus dysgalactiae Streptococcus uberis E. coli Pseudomonas spp. Trueperella pyogenes
69
What are some of the minor mastitis pathogens?
Coagulase negative staphylococci (CNS) Staphylococcus epidermidis Corynebacterium bovis
70
What is indicated by minor pathogen mediated mastitis?
Minor pathogens indicate problems with the teat dips/spray or damage to the teat skin. As these can allow these pathogens which typically live on the skin to colonise the teat canal or enter via damaged skin and cause mastitis
71
Which types of mastitis are most commonly seen with Staphylococcus aureus? | G+ bacteria, contagious, major pathogen
Subclinical mastitis *(high SCC)* Moderate to severe clinical mastitis Chronic mastitis
72
Why is Staphylococcus aureus so challenging to treat?
Staphylococcus aureus is so challenging to treat as it can invade and hide within the mammary epithelial cells lining the teat canal and teat sinus/cistern, and can form a biofilm so antibiotic penetration is poor. Staph. aureus is also an intermittent shedder, meaning it is more challenging to detect
73
Which signalement of cows are typically more susceptible to Staphylococcus aureus mastitis?
Older cows are typically more susceptible to Staphylococcus aureus mastitis
74
Which type of mastitis is most commonly seen with Streptococcus agalactiae? | G+ bacteria, contagious, major pathogen
Subclinical *(high SCC)*
75
(T/F) Streptococcus agalactiae is not very responsive to antibiotic treatment
FALSE. Streptococcus agalactiae is very responsive to antibiotic treatment
76
Why is Streptococcus agalactiae relatively easy to treat and control?
Streptococcus agalactiae is not an intermittent shedder so it is easier to detect and culture, and overall it is very responsive to antibiotic treatment - making it easier to treat and control
77
What is the main species of mycoplasma which can cause mastitis in cows? | Contagious pathogen
Mycoplasma bovis
78
Which clinical signs present along with mycoplasma spp. mastitis?
Respiratory signs Lameness
79
Why is mycoplasma spp. mastitis so challenging to treat?
Mycoplasma have no cell wall so will be resistant to beta lactams, and most antibiotics used for lactating and dry cow therapy are pencillin based. Furthermore, mycoplasma is intracellular to can hide in the tissues, and it forms a biofilm which reduces antibiotic penetration
80
What are the key indicators of contagious mastitis within the herd during the lactation period?
1. Recurring or chronic clinical mastitis cases 2. Mastitis treatment failures 3. High somatic cell count (SCC) with or without clinical cases 4. 'Climbing' bulk tank somatic cell count (SCC) 5. Milk culture results identifying contagious pathogens 6. Over 10% of the herd have over 200 000 cells/ml on the herd test/milk test somatic cell count (SCC) 7. High mastitis rate/SCC in heifers newly entering the herd for lactation
81
How do you treat and manage contagious mastitis within the herd?
1. Regularly monitor for clinical cases and somatic cell counts (SCC) so you can rapidly remove infected cows from supply and treat them so they don't infect other cows 2. Extended lactational cow therapy 3. Dry cow therapy
82
How do you prevent contagious mastitis within the herd?
1. Cull the 'problem' cows, i.e. the cows with recurring, chronic clinical infections or chronically increased somatic cell counts (SCC) 2. Pre-milking and post-milking dipping/spraying 3. Maintainence, cleaning and disinfection of the milking machine 4. Ensure milkers wear gloves when hand milking 5. Regularly monitor for clinical cases and somatic cell counts (SCC) so you can rapidly remove infected cows from supply and treat them so they don't infect other cows
83
Where is Streptococcus dysgalactiae commonly found? | G+, environmental, major pathogen
Surrounding environment Teat skin Tonsils of the cows *(so can be spread through cows suckling on other cow's teats)*
84
What are the risk factors for Streptococcus dysgalactiae mastitis?
Unhygienic environment Teat lesions Milking trauma
85
Which signalement of cows are typically more susceptible to Streptococcus dysgalactiae mastitis?
Heifers Dry cows
86
Where is Streptococcus uberis commonly found? | G+, environmental, major pathogen
Surrounding environment Teat skin
87
Which types of mastitis are most commonly seen with streptococcus uberis?
Subclinical mastitis *(high SCC)* Clinical mastitis
88
(T/F) Streptococcus uberis is very challenging to treat
TRUE. It is not very responsive to antibiotic treatment due to capsule formation *(however this is specific to UK and US strains, strains elsewhere in the world are more responsive to antibiotics)*
89
Where are coagulase negative staphylococci (CNS) commonly found? | G+, environmental, minor pathogens
Coagulase negative staphylococci (CNS) is mainly found on the teat skin
90
(T/F) Coagulase negative staphylococci (CNS) are resistant to antibiotics
FALSE. Coagulase negative staphylococci (CNS) are responsive to antibiotics
91
What is indicated by coagulase negative staphylococci (CNS) mastitis?
Coagulase negative staphylococci (CNS) mastitis indicates there is something wrong with the teat dipping/spraying
92
Where is E. coli commonly found? | G negative, environmental, major pathogen
E. coli is found within organic material (e.g. faeces and bedding) in the cow's surrounding environment
93
Which mastitis grade is typically associated with coliform mastitis?
Coliform (E. coli) mastitis is typically acute severe clinical mastitis which can progress to gangrenous mastitis
94
Why should you not use antibiotics to treat coliform mastitis?
E. coli will enter through the teat canal and establish infection, however they are transient pathogens, so will quicky die and release endotoxins. It is the endotoxins and endotoxaemia, and the host's immune response, which cause the clinical signs of coliform mastitis. So by the time you see clinical signs, the bacteria will be dead so there is no point of treating these animals with antibiotics
95
How should you treat coliform mastitis? | Coliform mastitis is a veterinary **emergency**
IV fluid therapy followed by oral fluid therapy NSAIDs Milk out the affected quarter Supportive care
96
How often should you milk out the affected quarter in a cow with coliform mastitis?
Milk out the quarter every 6 hours
97
What should you do if a cow has developed gangrenous mastitis?
Cows with gangrenous mastitis should be culled as the gangrene will cause sloughing of the tissue
98
What is the main source of pseudomonus spp. mastitis? | G negative, environmental bacteria
Contaminated water
99
Which mastitis grade is typically associated with pseudomonus spp. mastitis?
Gangrenous mastitis
100
What is the main source of Trueperella pyogenes mastitis? | Gram +, environmental bacteria
Trueperella pyogenes is typically spread via flies that have been in contact with an environment contaminated with Trueperella pyogenes
101
What type of mastitis is seen with Trueperella pyogenes infection?
Severe clinical mastitis characterised by lots of pus in the milk. These cows often 'lose' their affected quarter as it becomes so scarred and too damaged to produce milk
102
What is the main source of yeasts which can cause mastitis?
Wet bedding and surrounding environments can harbour yeasts which can cause mastitis
103
(T/F) Yeast mediated mastitis is easy to treat
FALSE. Yeast mediated mastitis is challenging to treat as they are not responsive to antibiotics, and antifungal drugs are rarely approved or effective in dairy cattle, so often these animals require culling
104
What are the key indicators of environmental mastitis within the herd during the lactation period?
1. Increased incidence of clinical mastitis in early lactation 2. High bulk milk tank somatic cell count (SCC) in early lactation 3. Isolation of environmental pathogens on milk culture 4. Treatment success 5. Poor environmental hygiene
105
Why does enviornmental mastitis tend to peak during early lactation?
Many cases of environmental mastitis begin during the dry period when cows are at a higher risk of becoming infected, however these infections often remain subclinical during the dry period. However, it becomes more clinically apparent during early lactation when the cow's immune system is suppressed *(due to just calving)*
106
How do you treat and manage environmental mastitis within the herd?
1. Prompt diagnosis and treatment through monitoring for clinical cases and carrying out somatic cell counts (SCC) so you can rapidly remove infected cows from supply 2. Lactational cow therapy 3. Dry cow therapy
107
How do you prevent environmental mastitis within the herd?
1. Pre-milking and post-milking dipping/spraying 2. Improve environmental hygiene 3. Effective and hygienic dry cow management 4. Assess teat condition (is there lesions, milking trauma, etc.) 5. Prevent milk dripping pre-calving 6. Improve nutrition to reduce faecal contamination *(i.e. reduce diarrhoea)* 7. Use teat emollients in the teat dip/spray
108
What is lactating cow therapy?
Lactating cow therapy is intramammary antibiotic treatment used to treat active clinical mastitis in cows during the lactational period. These are short acting intramammary antibiotics which are infused and milked out the next day, infused again, milked out, etc. until the course of treatment is complete ## Footnote Remember cows being treated with antibiotics need to be removed from the milk supply, and you must adhere to the milk withdrawal
109
Why should you prevent milk dripping pre-calving?
You should prevent milk dripping pre-calving as this will interfere with the teat spincter and seal which increases the risk of environmental mastitis when the cow is still in the dry off period leading up to calving. You can do this by feeding lower quality forage
110
What is dry cow therapy?
Dry cow therapy is an umbrella term for intramammary antibiotic treatment and teat sealant to treat an existing infections at the end of lactation and beginning of dry-off, and to prevent any new infections during the dry-off period. The antibiotics are long-acting intramammary antibiotics which are formulated to remain within the udder during involution
111
What is udder involution?
Udder involution is the regression of the mammary tissue back to a non-secreting state after milking has stopped *(i.e. the cow has been dried off)*
112
Why are cows at an increased risk of mastitis during udder involution and dry-off?
1. After cow's are dried off, milk will remain stagnant in the udder. This milk contains nutrients and provide a warm, nutrient rich environment for bacteria 2. If there is delay in the formation of the keratin plug, bacteria can enter the udder via the teat canal 3. If there is no milking, the bacteria is not being flushed out 4. Teat dipping/spraying is stopped at dry-off 5. Casein and fat levels remain high due to the stagnant milk within the udder, which inhibit white blood cell function
113
Can you dry off a quarter with antibiotic after it has been dry for a while?
No, as dry cow therapy is most effective when given at dry-off, before the teat canal seals and involution begins. It's not meant to be used after a quarter has been dry for an extended period. You risk breaking the keratin plug during insertion, the intramammary antibiotic won’t distribute properly because there's no active milk flow, and there is no proven benefit to administering antibiotic after involution has progressed
114
How do you reduce milk production if the cow is producing too much milk at dry-off?
1. Reduce feed/energy intake using a roughage based diet, avoiding rich silage and concentrates 2. Reduce milking frequency leading up to dry-off
115
What do you do with a clinical mastitis case at dry-off day?
If the cow has active clinical mastitis, you should delay dry-off and treat this cow with lactational cow therapy until she has recovered (as the process of stripping the milk is so important in treating clinical mastitis) and then dry her off and carry out dry cow therapy
116
How do you approach a herd investigation of mastitis?
1. Farm history 2. On-farm investigation 3. Data analysis 4. Written report 5. On-farm discussion
117
What should you assess to gather information on the farm history?
Bulk tank somatic cell counts (SCC) Bulk tank total bacterial count (TBC) Bulk tank bactoscan Individual cow somatic cell counts (SCC) Farm clinical records Milk samples (from clinical and subclinical cows)
118
What history questions should you ask to gather information on the farm history?
1. Ask questions to gather a generic farm history 2. How do you carry out lactational and dry cow therapy? 3. Lactational cow management? 4. Dry cow management? 5. What are your mastitis monitoring policies? 6. Who is monitoring for clinical mastitis cases? 7. When are you monitoring for clinical mastitis? It is as the milking cups go on or come off? 8. What is your protocol if clinical mastitis is detected? 9. What are the details of your supermarket contract for the milk? 10. Which teat dips/sprays do you use?
119
Why is it better to monitor for clinical mastitis cases as the milking cups go on rather when the come off?
It is better to monitor for and identify clinical mastitis cases before the cups go on, as if you don't detect it until after the milking cups are taken off, that cow with clinical mastitis has already been milked and their milk will already be in the bulk tank
120
How do you carry out milk sampling for bacteriology?
1. Wear gloves 2. Discard the first several streams of milk 3. Pre-dip/spray the teat 4. Dry the teat 5. Scrub the teat end with 70% alcohol 6. Hold a sterile tube at a 45° angle to collect your milk sample 7. Refrigerate the sample at less than or equal to 4°C and culture within 48 hours, or immediately freeze the samples
121
When investigating herd mastitis, which milk samples should you collect?
Milk sample all new clinical cases of mastitis that have not been treated yet Milk sample the subclinical cases with high somatic cell counts (SCC)
122
What kind of milk samples can you take for subclinical mastitis cases?
1. California Mastitis Test (CMT) can be used to identify affected quarters and sample only those 2. Composite milk sample (sample from all four quarters in one sample pot)
123
What information can the clinical milk samples give you during a herd mastitis investigation?
Clinical mastitis milk samples can identify the causative pathogens involved in the clinical cases
124
What information can the subclinical milk samples give you during a herd mastitis investigation?
Subclinical mastitis milk samples can indicate the circulating bacterial populations in the subclinical cases
125
What should you assess during the on-farm investigation of herd mastitis?
1. Milking routine 2. Teat dip/spray 3. Teat end scoring 4. Timings at milking 5. Cow hygiene scoring 6. Cow comfort at milking 7. Cow accommodation 8. Milking machine
126
What should you assess during the milking routine during the on-farm investigation of herd mastitis?
Observe the cows in the collecting yard Observe the cows as they enter the parlour Milking hygiene Milk cluster application and removal Clinical mastitis detection
127
What should you determine as you observe the cows in the collecting yard and as they enter the parlour?
What is the cow flow like? Do they use a backing gate to move the cows? How do the milkers interact with the cows? Do they use the 'leapfrog' technique when milking?
128
What does the 'leapfrog' technique refer to in the dairy industry?
The 'leapfrog' technique refers to the way the milkers move between cows during the milking process. Instread of milking cows in strict numerical order, the milkers will alternate postitions to maximize continuous workflow
129
What should you determine as you observe milk hygiene?
How do they use water during milking? What is the udder preparation routine? What is the milking machine hygiene like? What PPE are they milkers wearing?
130
Why is it so important to assess water use during milking?
It is important to assess water use during milking as if the milkers start spraying the cows with a high pressure hose during milking, this can aerosolise pathogens which can be a risk factor for mastitis
131
What should you determine as you observe milk cluster application and removal?
Do you have to physically break the vacuum to remove the milk clusters or are they automatic cluster removal systems (ACRs)?
132
What should you determine as you observe clinical mastitis detection?
Do they strip out the milk to assess for clinical mastitis as the cups go on or come off? Do they know what protocol to follow if they do detect clinical mastitis?
133
What aspects of the teat dip/spray should be evaluated during an on-farm investigation of herd mastitis?
1. Product used? 2. Contact time between the dip/spray and the teat skin? 3. How much of the dip/spray is being applied? 4. What is the coverage of the teat like? 5. How often is the teat dip/spray mixed up if it is not pre-made? 6. What is the percentage of emollient in the teat dip/spray? 7. How is the teat dip/spray stored? 8. What is the method of teat dip/spray application? 9. Are the teat dips/sprays being contaminated with water?
134
(T/F) Chlorhexidine is the ideal choice for teat dips/sprays
FALSE. Iodine is the ideal choice for a teat dip/spray as iodine kills all pathogens, whereas chlorhexidine has been shown to be habitable by multiple pathogens
135
How much teat dip should be applied per cow?
10ml of teat dip per cow
136
How much teat spray should be applied per cow?
15ml of teat spray per cow
137
How can you determine the coverage of the teat with teat dip/spray?
You can carry out the paper towel test where you gently blot the teat with paper towel to check for even staining. A patchy paper towel indicates inadequate coverage
138
What are emollients?
Emollients are substances such as glycerol and sorbitol which act to moisturise the teat skin which improves skin condition to maintain integrity and skin barrier function
139
Why is it important to assess the storage of teat dips/sprays?
If teat dips/sprays are being stored somewhere where they are being contaminated with organic matter (e.g. faeces), this can denature the product. Furthermore, storing the teat dips/sprays in direct sunlight can also denature the product - especially iodine
140
What is the pathogen of concern if teat sprays/dips are being contaminated with water?
Pseudomonas spp.
141
How many cows should you assess during teat end scoring?
You should score approximately 50 cows to get a representative sample size, assessing the teat ends as the milk cups come off the cows during milking
142
What should you assess during teat end scoring?
Is there any discolouration? Is there any oedema? Is there any hyperkeratosis? Is the teat orifice open or closed? Are there teat lacerations? Are they any teat warts (fibropapillomas)?
143
What kind of teat discolouration can you see during teat end scoring?
Pigmented Red Blue *(cyanosis)*
144
When is intervention and further investigation indicated during teat end scoring?
Over 20% of teats have red or blue discolouration Over 10% of teats have petechial haemorrhage Over 20% of teats have teat oedema Over 20% of teats have rough or very rough hyperkeratosis
145
What should you assess if over 20% of the teats are abnormal during teat end scoring?
Is there excessive vacuum pressure during milking? Are there pulsation problems during milking? Are the liners of the cups perished or worn? Are the cows being overmilked? Are the milk clusters being removed without releasing the vacuum seal? | All of these factors can lead to teat end damage
146
Which timing-related factors during milking should be examined as part of a mastitis investigation?
1. Udder preparation time 2. Overmilking time 3. Undermilking time 4. Delayed milk letdown
147
What should the udder preparation time be before milking?
Udder preparation should be a minumum of 15 seconds, but you're aiming for 60-90 seconds before the clusters are applied
148
What is overmilking?
Overmilking is when the clusters are still attached and milking the cow for over 90 seconds after milk flow has stopped
149
What is undermilking?
Undermilking is when the cow is not milked thoroughly or sufficiently during milking. This can be indicated by large volumes of residual milk after the milk clusters have been removed. There should be less than 100mls of residual milk per quarter for over 80% of cows, if not, the herd is being undermilked
150
What is delayed milk letdown?
Delayed milk letdown is where over 15% of the herd take more than 20 seconds for milk letdown
151
What is poor cow hygiene typically associated with?
Poor cow hygiene is typically associated with indoor housing systems and overstocking
152
When would a herd be classified as having a major environmental hygiene problem?
If over 30% of the herd score over 3 or 4 on the cow hygiene scale, then there is a major environmental hygiene problem which is likely to be a major contributor to mastitis
153
Which factors should you assess to determine cow comfort at milking?
How many times are the cows kicking/stepping as the milk clusters are on? How often are the cows swishing their tails? How often are the cows vocalising?
154
Which cow accommodation factors should you assess during an investigation of herd mastitis?
Dimensions Stocking density Bedding material Environmental hygiene Ventilation Cow behaviour
155
What are the three main types of milking parlour?
Rotary abreast Herringbone Swing-over herringbone
156
What are the two types of tests you can do to assess milking machine function?
Dry test Wet test
157
What is a dry milking machine test?
A dry milking machine test involves evaluating the performance and condition of the milking machine when the cows are not attached to the machine
158
What is a wet milking machine test?
A wet milking machine test is a performance test conducted on the milking machine while it is operating under normal milking conditions, i.e. the cows are attached to the machine
159
Which milking machine factors should you assess during herd investigation of mastitis?
1. Milking machine hygiene 2. Positioning of the milk clusters on the cow 3. Milking machine liners 4. Vaccuum stability 5. Pulsation
160
Which factors can you assess to evaluate milk machine hygiene?
Are the liners, pipelines, and milking equipment being cleaned and disinfected with the correct volumes of water, at an adequate temperature, with suitable mechanical action
161
Which factors should you assess when evaluating the positioning of the milk clusters on the cow?
Do the milk clusters hang squarely? Are the milking tubes twisted? Are the milking tubes the correct length? Are the long pulsation tubes the correct length? Is it the cow conformation that is the problem rather than the clusters?
162
Which factors should you assess when evaluating the milking machine liners
What is the condition of the liners? How often are the liners being changed? Is there liner slippage?
163
Why is the condition of the liners of the milking machine so important?
The condition of the liners is so important as as the liner ages, it loses elasticity which means they can't allow for proper milk ejection from the cow's udder. Old liners also have microscopic cracks which can harbour pathogens
164
How often should rubber based linings be changed?
Rubber based linings should be changed every 2,500 milkings
165
How often should silicone based linings be changed?
Silicone based linings should be changed every 10,00 milkings
166
What is a key indicator of liner slippage?
Squeak sounds during milking can indicate liner slippage
167
What are the main causes of liner slippage?
Wet teats Worn liners Incorrect cluster position Low vacuum pressure
168
What is the difference between a low-line and a high-line milking plant?
The main difference between a low-line and a high-line milking plant is the position of the milk and vacuum lines relative to the milking clusters, with low-line systems being closer to the clusters, and high-line systems being further away from the clusters. This will have an effect on the vacuum requirements for the system
169
Which vacuum pressure is required for a high-line milking system?
44 - 48 kPa
170
Which vacuum pressure is required for a low-line milking system?
38 - 42 kPa
171
When is there a problem with the vacuum system?
If there more than a 2 kPa variation in the vacuum pressure during milking, there is a problem with the vacuum system
172
When should the vacuum pressure be measured?
The vacuum pressure should be measured at peak milk flow - which is 60 seconds after the milking clusters have been attached - for 120 seconds
173
What are the risks of a low vacuum pressure?
Liner slippage Decreased milk yield
174
What are the risks of a high vacuum pressure?
Teat end damage Test congesion Incomplete milking
175
How can you assess the pulsation of the milking machine?
To assess the pulsation of the milking machine you can put your thumb into the liner to assess if the pulsation is adequate or not
176
What is the ideal pulsation rate for the milking machine?
45 - 60 cycles per minute
177
Who should you contact for further investigation of you suspect a problem with the vacuum or pulsation of the milking machine?
Milking machine technician
178
Which data should you analyse when conducting a herd investigation of mastitis?
Bulk tank data Subclinical mastitis data Clinical data Calving data Herd profile Production data Teat end scoring
179
(T/F) All farmers must record both subclinical and clinical mastitis data
FALSE. Farmers do not have to record subclinical mastitis data, however they do tend to record clinical mastitis cases as they are legally obligated to record antimicrobial use on the farm
180
What information should you assess when looking at clinical mastitis data?
Date of event Cow identification number Affected quarter Date of treatment(s) Treatment(s) given Bacteriological results
181
What are you trying to determine when assessing clinical mastitis data?
Is there seasonality to these clinical mastitis cases? Which age groups are affected by clinical mastitis? Is there evidence of cow to cow transmission (contagious mastitis)? What is the treatment effectiveness?
182
How do you calculate the case rate per year for clinical mastitis?
183
What is the KPI target for the case rate per year for clinical mastitis?
Less than or equal to 30 cases of clinical mastitis per 100 cows per year
184
What is prevalance vs incidence?
Prevalance is the proportion of the population with a disease at a specific point in time. Incidence is the rate of new cases of a disease in a population over a defined period of time
185
How do you calculate the incidence of clinical mastitis?
186
What is the recurrence rate of clinical mastitis?
The recurrence rate of clinical mastitis refers to the percentage of quarters within the herd requiring repeat treatment for clinical masitis per year
187
How do you calculate the recurrence rate of clinical mastitis?
188
What is the KPI target for the recurrence rate of clinical mastitis?
Less than or equal to 10% of quarters per year requiring repeat treatments
189
What can be indicated by no growth on bacteriology from a milk sample from a cow with clinical mastitis?
Cow has been treated with antibiotics E. coli mediated infection Staphylococcus aureus mediated infection Poor sampling storage
190
Which questions do you need to ask if a farmer fails their antimicrobial residue test?
Which product was used? Was this product used off-license? How are animals undergoing antimicrobial treatment being marked and identified? Who carries out antibiotic treatment? Have you brought in any new cows recently?
191
How do you prevent failing the antimicrobial residue test?
1. Seperate the cows being treated with antimicrobials from the milking herd 2. Mark cows being treated with antimicrobials with red spray paint and tail tape 3. Record all treatments thoroughly 4. Store and label drugs correctly 5. Discard all milk from treated cows
MODULE 21 - B
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