Mastitis Treatment Flashcards
What is mastitis control at its simplest level?
When will current infections cure?
Mastitis at its simplest level is about the prevention of NEW infections in a herd….
In the modern dairy herd, cure of existing infection will occur during the dry period – recent research shows us this – pathogen specific cure rates are very high during the dry period, even for S. aureus
Infection can be from various environmental sources - how can we try to avoid or reduce this?
This could involve reducing infection pressure in buildings – loafing space, ventilation, water quality, water storage, bedding quality, bedding storage, scraping frequency, lying areas etc
This may also involve reducing infection pressure at pasture – stocking rates, back fencing, management of gateways, common loafing areas, fly control etc
–> much harder and more complex to address!
How can we prevent new infections from infected cows (to other cows?)
Often focussed on treatment and/or culling
Assumes infected cows transmit infection to uninfected herd mates
Reactive approach
Over-reliance on antibiotic treatment unsustainable
…transmission from other infected cows generally much easier to limit/stop (parlour)
Whilst Andy (who he, he sounds useful) has described approaches to treatment, we have to remember that this is not sustainable long term, particularly during the current climate (just thought this sentence was good but didnt wanna remove Andy)
As part of the treatment for mastitis, explain the aseptic infusion techqniue for administration of intra-mammary therapy?
As part of the treatment for mastitis, why do we use the aseptic infusion techqniue for administration of intra-mammary therapy?
Aseptic infusion technique
- Risk of new infection
- Coliforms (e.g. E. coli)
- Yeasts (e.g. Candida spp.)
- Important when treating clinical/subclinical inf.
- REALLY important when drying-off cows!
In theory and simple terms, how do we treat clinical mastitis during lactation?
Identify bacterial pathogen…
…select suitable antibiotic
…treat for suitable length of time…
Why, in practice, is mastitis treatment problematic, espeically during lactation?
Pathogen often unknown at time of treatment…!!!!
Vast majority of clinical mastitis cases are not treated by a veterinary surgeon… Farmers treat her. Otherwise you would be called out a lot.
Many factors, other than pathogen and choice of antibiotic, are the basis for success/failure. Mostly comes down to the cow!
Why is the pathogen often unknown at the time of treatment?
Reliant on farm staff to have aseptic sample collection technique…and remembering to sample!
A lot of interest in RAPID diagnostic plates (18-24 hours) to culture a Gram+ or Gram-
…but differentiating between some is very hard to do!
…and is a ‘no growth’ really a no growth…? Or have we not left it long enough?
This is mostly done on the farm.
Strep – Penicillin
E.Coli – may not need to treat?
BUT research SO FAR indicates culture-based treatment approaches associated with a poorer outcome
What are the key points for mastitis treatment?
Many products available BUT VERY FEW comparative studies (dry or lactating products)
Dry cow therapy has much BETTER EFFICACY than lactating cow therapy for curing intra-mammary infections (Approx. 90% vs 50%). Much more likely to cure intra mammary when dry (90%+) then in lactation
WHY?
Trying to treat infection when full of milk = harder
Hostile environment when not in milk = easy.
AB dry cow products- more mg of product (not worried about withdrawal) and last above MIC for longer
MORE VARIATION between COWS, FARMS & PATHOGENS (and strains) than between products
DOSING STRATEGY (how long you treat for) and COW FACTORS are much more important than choice of product…
If the farmers missed clinical signs at the 1st millking, what is the chance of cure? Why?
RAPID IDENTIFICATION IS CRUCIAL…
1st milking critical
If miss clinical signs the chance of cure is reduced by 40-50%… Infection more established and late getting to it
Examine MILK, UDDER and COW
What is grade 1,2 and 3 of mastitis?
Grade 1: milk changes only
Grade 2: milk changes and swollen udder
Grade 3: above…plus cow is ill
How and what COW and FARM factors can affect chance of cure?
COW and FARM factors affect chance of cure…
The cow SCC, her parity (how many calving’s, 3 calving’s probably about 5yo), age and # quarters affected…
The farm bulk milk SCC and prevalence of infection… High cell count where likely to be staphs? Or low likely to be cloiforms
How useful are antibiotics with regards to treating mastitis?
ANTIBIOTICS ARE WORTHWHILE
But not 100%…
Antibiotics cure symptoms
~ 90%? Got rid of sign or clots; may not have actually got rid of the infection
Antibiotics cure bacterial infection
~50-60%?
Non-antibiotic treatment much less! My get 80% symptomatic and 30% pure cure
With pathogens, do gram positive or negative not often need a long course of treatment?
…what about Gram-negative pathogens?
Often don’t need a long course of treatment
What should the route of antibiotic be?
ROUTE OF ANTIBIOTIC SHOULD BE INTRA-MAMMARY
Little evidence that injectable (systemic) antibiotic treatment is better…
…or that it improves cure rate in combination
Why is duration of treatment important?
DURATION of treatment is important
The vast majority of antibiotic tubes are NOT used per data sheet. If you follow this you can then put milk back in tank according to the sheet
Minimum three days?
Extended treatment improves chance of cure – consider 5 to 8 days?
Can chance of cure be 100% in lactation?
Remember chance of cure is never 100% in lactation
If you have a HIGH cell count herd, Typically bulk milk SCC>200 cells/ml, what pathogens are more likely?
‘Contagious’ mastitis pathogens more likely Gram-positive pathogens predominate
e.g. S. aureus, Enterococcus spp., S. uberis
With a HIGH cell count herd, what therapy should you consider?
CONSIDER extended intra-mammary therapy
e.g. twice daily 5 days
Good activity v Gram-positives – penicillin!
If you have a LOW cell count herd, what pathogens are more likely?
Typically bulk milk SCC<200 cells/ml
‘Environmental’ mastitis pathogens more likely Gram-positive and Gram-negative pathogens
e.g. S. uberis, E. coli, other coliforms
If you have a LOW cell count herd, what therapy should you consider?
CONSIDER intra-mammary therapy – all cases?
Broad spectrum – penicillin & aminoglycoside
Importance of NSAIDs for severe cases
If the farmer says ‘my mastitis tubes arent working’, what should you consider on your checklist to ask the farmer about?
- A few ‘problem’ cows or herd? – trying to treat a cow which has had 6 cases since calving? Or is this a herd thing?
- Speed of detection
- How is this done? Every milking? How often do you examine fore milk?
- Length of treatment course
- Minimum 3d, consider extending to 5?
- Pathogens – bacteriology for NEW cases
- S. aureus or Mycoplasma spp. (rare)
- Klebsiella spp., Pseudomonas spp. Hard to get rid of anyway
- Which cows are being treated?
- Old, chronic infections?
- These will have poor cure rates - need alternatives!
What is Streptococcus agalactiae?
An obligate udder pathogen, susceptible to antibiotic treatment
How can we eradicate Streptococcus agalactiae?
How can we treat it?
Whole herd treatment at one time (a ‘blitz’) can eradicate the organism – although this may not be required
MUST ensure all dry cows received antibiotic Dry Cow Therapy
Variety of protocols – usually using a short acting penicillin tubes for each cow
What pathogen can cause toxic mastitis?
Severe E. coli mastitis (‘toxic’ mastitis)
What treatment does toxic mastitis require?
Grade 3 cases…often VERY sick - Endotoxaemia
Require INTENSIVE treatment and management
FLUID THERAPY and NSAIDs are the MOST IMPORTANT aspects of treatment
Antibiotics play a very LIMITED role!
As part of the Treatment for of HIGH CELL COUNT (‘subclinical mastitis’) during lactation:
In cows with SCC >200,000 cells/ml, which pathogens are most like be infecting them?
Why do we decide to treat them? Do we NEED to treat them? When are we best to treat?
Cows with SCC>200,000 cells/ml more likely to be infected with Gram+ pathogens?
Risk of spread to other cows in the herd?
Could be a reservoir of infection and spread to others. (reason to electively treat).
Do we NEED to treat these cows?
Often POOR CURE RATES (10-30%) in lactation
If we don’t have high milk tank counts and a low rate do we need to treat the reservoir?
BEST TO WAIT UNTIL DRY COW THERAPY AT THE END OF LACTATION IF POSSIBLE!
We know she will get better in the dry period..
How do we treat high somatic cell count cows in lactation?
TREATING HIGH SCC COWS IN LACTATION
Identify quarter(s) affected
Extended courses of intra-mammary tubes (7-8 days)
OR dry off quarter? Stop milking the persistent ¼
OR cull cows if very chronic infection?
When is the optimal time to achieve a cure during a lactation cycle?
The Dry Period
The optimal time to achieve a cure…
Treat existing intra mammary infection!
Look at this decision tree for drying off cows and whether to treat - sorry didnt know how to put into a question!
How can we describe an UNIFECTED cow?
e.g. <200,000 cells/ml for the last THREE recordings…
NO clinical mastitis in last 3 months
How can we describe an IFECTED cow?
e.g. >200,000 cells/ml on ONE or MORE of the last THREE recordings…
and/or clinical mastitis in last 3 months. Cow that probably is infected (cant say she isn’t!!)
What is selective dry cow therapy for unifected cows?
UNINFECTED COWS
Low SCC cows
PREVENT infection (e.g. environmental Streptococcus spp. or coliforms
Internal sealant only
What is selective dry cow therapy for ifected cows?
High SCC cows
(+/- bacteriology for which pathogen?)
CURE infection
Antibiotic with Gram positive efficacy AND internal teat sealant
What are internal teat sealants?
What are some qualities and how are they used?
e.g. how long do they persist,
- Bismuth subnitrate in paraffin base
- Designed for use in uninfected cows
- Persistent (>100 days)
- No inherent antimicrobial activity
- Care with infusion!
- Residual seal can be mistaken as mastitis at calving
- Infused and left in the teat cistern
- Put something into the canal to prevent the risk of colonising.
- Must be clean!!! Otherwise you can cause an infection and then they can drop dead through toxic mastitis.
There is evidence to suggest that administration of antibiotic dry cow therapy to uninfected, low cell count cows at drying-off may increase the risk of WHAT?
Evidence to suggest that administration of antibiotic dry cow therapy to uninfected, low cell count cows at drying-off may increase the risk of coliform mastitis infections in the next lactation…
Name some ‘minor’ mastitis pathogens
- Corynebacterium spp.
- Contagious pathogen
- e.g. C. bovis
- Coagulase Negative Staphylococcus spp. (CNS)
- Lots of different species
- S. hyicus, S. epidermis, S. haemolyticus etc
- Environmental sources
- May be important in heifers..
Beware a diagnosis from bacteriology – might not be causal…often have failed to culture a causal major pathogen such as E. coli
With regards to the pathogen(s) Corynebacterium spp, Contagious pathogen e.g. C. bovis
How prevalent is it? How contagious?
Most prevalent mastitis pathogen
Highly contagious
Colonises the streak canal
Very slow growing (72hrs?)
High prevanlence of Corynebacterium spp., Contagious pathogen, e.g. C. bovis may be a marker of what?
High prevalence may be a marker of poor post milking teat disinfection
With Coagulase Negative Staphylococcus spp. (CNS), Lots of different species, S. hyicus, S. epidermis, S. haemolyticus etc - what are sources?
What are some qualities of this ‘minor’ mastitis pathogen?
Environmental sources
May be important in heifers..
- Importance equivocal
- Cause more marked increase in SCC than C. bovis
- Can also colonise the streak canal
- Large numbers self cure
- Can cause clinical mastitis
- Can cause re-infection post-treatment
- Considered to be of great importance in Israel and Scandinavia
When does summer mastitis happen?
What are the pathogens that cause it?
‘Summer’ Mastitis
Does not happen in summer! Refers to a syndrome of infection
Trueperella pyogenes, Peptococcus indolicus & Streptococcus dysgalactiae
What is the aetiology of summer mastitis?
Complex aetiology, combo of:
- Arcanobacterium (Trueperella) pyogenes
- Peptococcus indolicus
- Streptococcus dysgalactiae
- Producing swollen udder producing caseous stuff. Will save her but not the udder. Have to drain it!! Cow is very sick.
Which cows are mostly affected with summer mastitis?
What can it infect?
What is it transmitted by?
- Disease of dry cows and heifers (not in lactation)
- Can infect young calves, and even bulls and steers
- Transmitted by Hydrotea irritans (Sheep head fly) - but not the whole story. But can get infection all year round
- May occasionally occur in the winter!
What are the clinical signs of summer mastitis complex?
Prognosis?
- Hot, hard, swollen, painful quarter
- Characteristic foul smell
- Cow often lame
- Often goes undetected
- Can lead to abortion
- Prompt identification and treatment essential
- Prognosis poor, quarter often lost
What is the treatment of summer mastitis complex?
Treatment
- Intramammary antibiotics useless!
- Systemic penicillin or derivatives
- Regular stripping
- May need to institute drainage by removing teat / cutting vertically
- Generally lose the affected quarter
How can you control summer mastitis complex?
Control
- Fly avoidance (specific pastures)
- Fly control (spray, pour-ons etc.)
- Dry Cow Therapy (repeat infusions)
- Teat Sealants (Internal and External)
- Stockholm Tar, micropore tape etc.
