Control of mastitis Flashcards

1
Q

CONTAGIOUS mastitis - where does organism tend to live? How does it cause infection? When?

A

Organisms prefer to live in the udder and teat skin
Often cause subclinical infection
Mostly spread from cow to cow at milking

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2
Q

Examples of contagious mastitis pathogens 4

A

S.agalactiae
S.dysgalactiae
S.aureus
(S.uberis - but originally an environmental organism)

Be aware there are others!
Minor pathogens include:
Corynebacterium bovis
Coagulase-negative Staphylococci (CNS)

Unlikely to be pathogenic. May have protective function.

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3
Q

ENVIRONMENTAL mastitis - where does organism tend to live? How does it cause infection? When?

A

Live in the environment
Sporadically gain entry to the udder
Tend to either be rapidly eliminated or cause very serious mastitis
But if quarter is infected during dry period can persist and cause problems in early lactation
From dirty environment but can gain entry at milking tie.
Other important factors:
-housing design and management
-cubicle design
- yard management
- scraping of dung
- dry cow housing

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4
Q

Which environmental organisms are most responsible for environmental mastitis cases? 7

A

Coliforms and E.coli
Also S. uberis and Klebsiella
Rarely but possibly Bacillus cereus, fungi and yeasts

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5
Q

Which cells make up a SCC? 2 When are these high? 2

A

inflammatory (increase with bacterial infection) and epithelial (these increase towards the end of lactation and are high immediately after calving)

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6
Q

What is the SCC for a.) clinical mastitis b.) subclinical mastitis?

A

a. ) millions of cells/ml

b. ) >200,000 cells/ml

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7
Q

Outline the features of subclinical mastitis

A

tends to go undetected and survive in quarters for long periods, causes prolonged mildly elevated SCC of quarter >200,000, tends to spread at milking time, can get many quarters in the herd infected each with a high cell count, tends to be contagious organisms, a high number of subclinical infections will cause elevated bulk tank SCC, so bulk tank SCC is an approximate indication of the proportion of quarters that are infected, indicator of the PREVALENCE of mastitis

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8
Q

Define BMSCC

A

Bulk milk somatic cell count

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9
Q

What are the important values of the BMSCC (4)?

A

Target = 200,000/ml

Milk cannot go for human consumption by EU law if > 400,000/ml

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10
Q

What are the important features when trying to control CONTAGIOUS mastitis?

A

Control spread at milking time
Eliminate reservoirs of infection (dry cow therapy, culling and identify infected cows (subclinical) using individual cell counts)
DO THIS WITH THE 5 POINT PLAN

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11
Q

What is the 5 point plan?

A

For the control of contagious mastitis:

  1. ) Prompt detection and treatment of clinical cases
  2. ) Post-milking teat dip (PMTD)
  3. ) Dry cow therapy
  4. ) Cull persistent offenders
  5. ) Regular servicing and maintenance of milking machine
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12
Q

How should cases be promptly detected?

A

Detect in parlour, do fore milking (make 4-5 strips to make a visual assessment of the milk; also aids milk let down and flushes out the milk most laden with bacteria), Consider milk over floor (Strip Cup) and splash back

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13
Q

Important parlour hygiene tips - 4

A

Use individual paper towels - one per cow
Never use udder cloths
Wear gloves
Can use pre-milking teat dips to further improve hygiene.

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14
Q

What is PMTD? Why do this?

A

Post-milking teat dipping
WHY = teat orifice remains open for 30-40 minutes after milking, keep cows standing after milking to allow sphincters to close before they lay down as bacteria can be transferred onto teat skin during milking and bateria multiply and invade milk canal

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15
Q

What to use to PMTD?

A
Disinfectant which coats teat skin and kills bacteria. Also can aid in maintaining teat skin in good condition. EXAMPLES:
IODOPHORES
CHLORINE BASED
CHLORHEXIDINE
QUATERNARY AMMONIUM COMPOUNDS
Several other agents too
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16
Q

How to apply PMTD? 3

A

dip cup
spray
automatic exit systems

LOOK TO SEE HOW GOOD COVERAGE IS

17
Q

What is DCT?

A

Dry Cow Therapy

18
Q

What are the 2 main DCT options?

A

LONG ACTING ANTIBIOTICS - aims to remove existing subclinical infections during the dry period, all quarters infused with a LA AB at last milking, greatly improved efficacy over lactation therapy, also aims to help prevent further infections gettting established in the udder during the dry period.
TEAT SEALANT - inert substance which is infused into teat canal and blocks it - prevents bacteria entering during the dry period, can infuse all quarters with AB at last milking OR infuse only those with evidence of infection (SCC > 200,000/ml), can use teat sealant on all.

19
Q

What must happen when you are doing DCT?

A

excellent hygiene
PMTD must be used
Record and mark cow to prevent cow getting milked by accident
Follow witholding time and 96 hour post calving milk discard rule.

20
Q

Which mastitis cases should you cull?

A

Persistent offenders = 3 cases or more during one lactation; persistently high individual SCC which doesn’t respond to treatment.

DONT TAKE THIS DECISION LIGHTLY. CONSIDER CLINICAL SIGNS AND BACTERIOLOGY.

21
Q

What are the 3 possible actions you could take with a mastitis problem cow?

A

Put in a problem herd
Treatment at dry off
Cull

22
Q

How to regularly service and maintain the milk machine…

A

Don’t overlook this. Vets often not very confident at this so use mechanics/engineers.

23
Q

Describe the action of milking on the teat.

A

Constant vacuum applied at teat end but NOT to whole teat. Liner opens and closes (pulsation) to massage the teat otherwise it would get congested and very painful. Pulsation DOESN’T squeeze the milk out.

24
Q

What is the only part of the milk machine that comes into contact with the cow’s udder?

A

Liners - these must be changed frequently:

  • rubber = 2500 milkings
  • silicone = 10,000 milkings.
25
Q

How do you check the constant vacuum is working properly?

A

Must have plenty of vacuum reserve.
Test by opening 1 in 5 units, if vacuum drops by 2kPa it is insufficient
Vacuum recovery time should recover in <3 seconds

26
Q

Why are vacuum fluctuations bad?

A

They can cause retrograde movement of milk into the teat canal.

27
Q

What is a liner slip?

A

Air leaking into top of liner makes a distinctive sound.

28
Q

How should environmental mastitis be controlled?

A
  1. ) Control the cow’s environment

2. ) Parlour factors can be important, teat preparation essential, clean and dry at milk of applying milk cluster.

29
Q

What size should cow cubicles be? (length, width, barrier)

A

2.3m long
1.2m wide
Barrier 1.7 from back on floor

30
Q

Suggest 2 ways cow housing can be assessed

A

Comfort - laying times

Dig around in the bedding to look for signs