MASTITIS IN THE
AUSTRALIAN DAIRY
INDUSTRY
Insert presentation date here
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Mastitis in the Australian dairy industry
TABLE OF CONTENTS
1. ABOUT MASTITIS
2. A SURVEY OF MASTITIS PATHOGENS IN THE SOUTH EASTERN AUSTRALIAN
DAIRY INDUSTRY
3. CLINICAL MASTITIS
4. SUBCLINICAL MASTITIS
5. ANTIBIOTIC SENSITIVITIES
6. CONCLUSION
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Mastitis in the Australian dairy industry
ABOUT
MASTITIS
WHAT IS MASTITIS?
MASTITIS IS THE INFLAMMATION OF THE COW’S MAMMARY GLAND, USUALLY
CAUSED BY BACTERIA ENTERING THE TEAT CANAL AND MOVING TO THE UDDER.
THE TWO MAIN TYPES OF MASTITIS ARE CONTAGIOUS AND ENVIRONMENTAL
MASTITIS.
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Contagious mastitis
Environmental mastitis
Habitat
Inside udders or on teat skin
The cow's environment
(e.g. manure, soil)
How is it spread
Contamination from infected milk
Contamination from infected
environment; can be introduced with
intramammary tubes if teat ends are
not sterile when treatment occurs.
When is it spread
Milking time
Mainly at drying-off and around
calving time; most cases seen at
calving or early lactation.
Bacteria
Commonly Staph aureus and Strep
agalactiae
Commonly Strep uberis, E.coli,
coliforms, Pseudomonas. Many others
occur occasionally.*
Mastitis in the Australian dairy industry
* Source: Countdown Downunder
SUBCLINICAL VS CLINICAL MASTITIS
SUBCLINICAL MASTITIS
CLINICAL MASTITIS
(CHRONIC, MILD, ACUTE, SEVERE)
• Cow – no observable changes
• Udder – no observable changes
• Milk – no observable changes but significant
differences in milk composition
• Cow – spectrum from extremely unwell to no
observable changes
• Udder – spectrum from hot, swollen and painful
to no abnormalities
• Milk – displaying abnormalities from
discolouration, clots, blood, clots, flakes,
wateriness
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Mastitis in the Australian dairy industry
IMPORTANCE OF MASTITIS CONTROL
• Countdown Downunder has shown that every four clinical cases of mastitis cost around
$1,000
• These losses occur through:
– Lower production
– Lower payments for milk due to quality
– Increased costs of treatment and culling
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Mastitis in the Australian dairy industry
CELL COUNTS IN MILK
BULK MILK CELL COUNT (BMCC) SHOWS THE CONCENTRATION OF COW BODY
CELLS IN VAT MILK.
• BMCC is an Indirect measure of subclinical mastitis in the whole herd
• BMCC can provide a guide of infection levels in a herd
• Each 100,000 cells/mL indicates about 10% of cows are infected
Guidelines
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Below 150,000 cells/mL
Excellent mastitis cell count control
150,000 – 250,000 cells/mL
Good control. Meets level for premium payment
with most dairy companies
250,000 – 400,000 cells/mL
Moderate mastitis control and cell count control
Above 400,000 cells/mL
Poor / inadequate control. Milk not considered fit
for human consumption
Mastitis in the Australian dairy industry
* Source: Countdown Downunder
MASTITIS TREATMENT
ANTIBIOTIC DRY COW TREATMENT
TEAT SEALANTS
• Dry cow treatment is used to treat existing
infections and reduce the number of new
infections that may occur during the dry
period
• Teatseal is a non-antibiotic substance which
creates a physical barrier in the teat canal to
prevent new intramammary infections during the
dry period and reduce the incidence of clinical
mastitis in early lactation
• The most appropriate dry cow treatment
strategy should be planned with a veterinarian
• The choice of treatment will depend on a
number of factors, including the spectrum of
activity, cure rates and how long the cow has
been infected
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Mastitis in the Australian dairy industry
• Teatseal used in combination with an
intramammary dry cow antibiotic has been shown
to be more effective than an intramammary
antibiotic alone, reducing the rate of clinical
mastitis by up to 70%
INTERNATIONAL CONTEXT
THE AUSTRALIAN DAIRY INDUSTRY IS RECOGNISED FOR ITS RESPONSIBLE USE
OF ANTIBIOTIC TREATMENTS
• Internationally, the responsible use of antibiotics to treat mastitis has proven to be a
greater challenge
• After European policy makers expressed concern over the link between antibiotic use in
livestock and antibiotic resistance in humans, the Netherlands took its own stance and, in
2012, introduced penalties for failing to reduce on-farm antibiotic use including:
– Targeting 50% reduction in use
– New farm protocols in place, aimed at prevention
– Antibiotics used primarily for treatment rather than prophylactically
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Mastitis in the Australian dairy industry
JUDICIOUS USE
JUDICIOUS USE IS IMPORTANT TO MINIMISE THE DEVELOPMENT OF RESISTANCE
WHILE MAINTAINING EFFECTIVENESS TO PREVENT DISEASES
• Requires an understanding of pathogens involved
• Need to assess any changes in antimicrobial sensitivities over time
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Mastitis in the Australian dairy industry
A SURVEY OF
MASTITIS PATHOGENS
IN THE SOUTH
EASTERN AUSTRALIAN
DAIRY INDUSTRY
WHY CONDUCT A MASTITIS SURVEY IN
AUSTRALIA?
• Farmers often make the comment
“We need new antibiotics to treat mastitis because the bacteria are resistant to the
ones we currently have”
• Farmers often ask the question
“Do I need different antibiotics for different stages of lactation, different ages or
different regions?”
• Farmers will also question their vet
“Is this type of bacteria the standard cause of mastitis in Australia or is something
different happening on my farm?
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Mastitis in the Australian dairy industry
SURVEY OBJECTIVES
1
Determine the prevalence of clinical and subclinical mastitis pathogens in key dairy
producing regions
2
Investigate the impact that seasons, stage of lactation and lactation number have on
mastitis pathogen prevalence
3
Identify the current antibiotic sensitivity patterns for Australia’s most costly pathogens
in dairy cattle
4
Understand the relevance of currently available treatment options used in clinical
and subclinical mastitis therapy
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Mastitis in the Australian dairy industry
ABOUT THE SURVEY
SURVEY SAMPLES
SURVEY DESIGN
• Australia’s largest study into the prevalence of
mastitis pathogens in local milk producing
regions, including:
– 13 veterinary practices
– 65 farms
– 2986 clinical mastitis samples over 13
months
– 1038 subclinical mastitis samples
– All positive cultures submitted for culture
and sensitivity (CLSI approved
standards)
– All positive cultures archived
• Herd size: > 464 (210-1000) cows in milking herd
• Mean BMCC in previous year of 100,000500,000
• Herd testing on regular basis (minimum four tests
per year) and maintain electronic herd health
recording system
• Met acceptable animal welfare standards
• Project fully funded by Zoetis in 2010
• Collaborated with Dairy Focus to run the survey
throughout 2011 and early 2012
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Mastitis in the Australian dairy industry
CLINICAL
MASTITIS
OVERALL CLINICAL MASTITIS
CULTURE RESULTS
% of pathogens isolated
35
30
25
20
15
10
5
0
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Mastitis in the Australian dairy industry
OVERALL CLINICAL MASTITIS
CULTURE RESULTS
OVERALL, 39.3% OF SAMPLES WERE EITHER CONTAMINATED (16.1%) OR
PRODUCED NO GROWTH (23.2%)
• With the contaminated and no growth samples excluded the major pathogens are:
–
–
–
–
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54.3% Strep. uberis
14.8% Staph. aureus
11.7% E. coli
8.9% Strep. dysgalactiae
Mastitis in the Australian dairy industry
Total - 89.7%
WHAT DO THESE RESULTS MEAN
AT THE FARM LEVEL?
• One in six samples were contaminated at the time of collection
• Farmers were trained and supplied with all consumables required to collect samples
aseptically
• If contaminating bacteria are still present on the teat orifice at the time of collection - they
would still be present at the time the antibiotic treatment was infused
• If a cow is treated with three tubes of intramammary antibiotics per case of mastitis, she
will have a 50% chance of receiving a new infection due to poor hygiene!
• Important to treat the existing infection and not to introduce a new infection
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Mastitis in the Australian dairy industry
WHAT DO THESE RESULTS MEAN
AT THE FARM LEVEL?
• 54.3% Strep. uberis – environmental contaminant
• 14.8% Staph. aureus – cow associated bacteria
• 11.7% E. coli – environmental contaminant
• 8.9% Strep. dysgalactiae – cow associated bacteria
• The big four bacteria cause the majority of mastitis – no new super bacteria have
emerged
• Environmental bacteria have taken over from cow-associated bacteria as the leading
cause of mastitis
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Mastitis in the Australian dairy industry
CLINICAL
MASTITIS
STAGE OF LACTATION
CLINICAL MASTITIS VS
STAGE OF LACTATION
MAJOR PATHOGENS
ISOLATED DURING LACTATION
OUTCOMES
• The stage of lactation appears to have little
impact on the frequency of the major bacteria
40
35
• Strep. uberis was the dominant pathogen at all
stages of lactation and was consistently isolated
at a rate greater than 30%
Pathogen Isolated %
30
25
20
15
10
5
0
First month 2-6 months 7-10 months >10 months
Stage of Lactation
S. uberis
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S. aureus
E. coli
Mastitis in the Australian dairy industry
S. dysgalactiae
CLINICAL
MASTITIS
GEOGRAPHICAL REGION
CLINICAL MASTITIS VS
GEOGRAPHICAL REGION
MAJOR PATHOGENS ISOLATED BY REGION
40
Pathogen Isolated %
35
30
25
20
15
10
5
0
S. uberis
S. aureus
E. coli
Major Pathogen
Gippsland
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Mastitis in the Australian dairy industry
Northern Vic
Tasmania
Western Vic
S. dysgalactiae
CLINICAL MASTITIS VS
GEOGRAPHICAL REGION
MINOR PATHOGENS ISOLATED BY REGION
Pathogen Isolated %
2.5
2
1.5
1
0.5
0
A. pyogenes
C. bovis
Candida
spp/yeasts
Klebsiella Nocardia spp Pasteurella Serratia spp
spp
spp
Minor Pathogens
Gippsland
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Mastitis in the Australian dairy industry
Northern Vic
Tasmania
Western Vic
CLINICAL MASTITIS VS
GEOGRAPHICAL REGION
• Regional differences were minor
– Western District of Victoria recorded the highest incidence of Strep. uberis at 36.8%,
Gippsland recorded lowest at 27.5%
• Except
– Staph. aureus was recorded at 12.7% of cultures from Gippsland, but only 4.5% of
cultures from Northern Victoria
– E. coli was the second most likely pathogen in samples from Northern Victoria at an
isolation rate of 9.7%
– C. bovis was isolated at a rate of around 1.5% for the mainland states, yet only a single
isolate in Tasmania
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Mastitis in the Australian dairy industry
CLINICAL
MASTITIS
NUMBER OF LACTATIONS
CLINICAL MASTITIS VS
NUMBER OF LACTATIONS
MAJOR PATHOGENS
ISOLATED BY LACTATION NUMBER
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OUTCOMES
• Heifers produced the highest rate of Strep. uberis
infections; to manage this:
– Maintain a clean environment for calving
– Introduce a teat sealant
Pathogen isolated %
40
35
30
• Cows had broadly similar rates of infection with
the major bacteria regardless of their age –
similar treatment strategies will apply to all age
groups
25
20
15
10
5
0
1
S. uberis
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2
3
4
5
Lactation Number
S. aureus
E. coli
Mastitis in the Australian dairy industry
6
≥7
S. dysgalactiae
SUBCLINICAL
MASTITIS
SUBCLINICAL MASTITIS RESULTS
SUBCLINICAL MASTITIS
PATHOGENS ISOLATED
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IMPORTANT FINDINGS
• On a single occasion on some of the enrolled
farms, a further 20-30 samples were collected
from a selected group of cows that displayed a
high somatic cell count in mid-to-late lactation
Pathogen Isolated %
18
16
14
• No growth result for the subclinical mastitis
samples (17.4%) was broadly similar to the rate
calculated for the clinical mastitis samples
(23.2%)
12
10
8
6
• The frequency with which a contaminated sample
was submitted from cows with subclinical mastitis
(40.7%) was far higher than for clinical mastitis
submissions (16.1%)
4
2
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Mastitis in the Australian dairy industry
S. agalactiae
Serratia
Pseudomonas
Other
Candida/yeasts
Nocardia spp
Other Staphs
E.coli
C. bovis
S. dysgalactiae
s. uberis
S. aureus
0
CONTAMINATED SAMPLES - IMPLICATIONS
WHY DO WE SEE HIGHER RATES OF CONTAMINATION WHEN COLLECTING A
COMPOSITE SAMPLE FROM FOUR QUARTERS?
• The sterility of the four collectors is not maintained
• Sampling 20-30 cows rather than a single cow
• The sampling is conducted at the end of milking when more manure is present in the environment
• Sampling is seen as just ‘another job’ at the end of the milking session – a time when attention to
detail may not be a priority
• These cows will receive DCT shortly after this sampling procedure (antibiotics +/- teat sealant)
• The antibiotics commonly used will not necessarily cure the environmental bacteria that may be
infused into the udder if hygiene is poor
• Significant time and money is invested in applying DCT - the ROI is dependent on strict hygiene
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Mastitis in the Australian dairy industry
SUBCLINICAL MASTITIS RESULTS
SUBCLINICAL MASTITIS
MAJOR BACTERIA
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IMPORTANT FINDINGS
• Staph. aureus was the organism most frequently
isolated from subclinical mastitis samples
(17.5%)
Bacteria isolated %
70
60
• Strep. uberis returned 141 positive cultures
(13.1%)
50
40
• E. coli was only cultured on 10 occasions (0.9%)
from the samples submitted from high ICCC
cows
30
20
• Regional differences were minor; Staphs and
Streps were the predominant organisms likely to
be present in a high ICCC cow at the time of
drying off
10
0
Gippsland
Northern Vic
Tasmania
Data excludes no growth and contaminated samples
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Mastitis in the Australian dairy industry
Western Vic
ANTIBIOTIC
SENSITIVITIES
CLINICAL MASTITIS SAMPLES
STREP UBERIS
100%
98%
96%
94%
Resistant
92%
90%
88%
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Mastitis in the Australian dairy industry
Intermediate
Sensitive
CLINICAL MASTITIS SAMPLES
STAPH AUREUS
100%
100%
99%
99%
98%
98%
97%
97%
96%
96%
95%
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Mastitis in the Australian dairy industry
Resistant
Sensitive
CLINICAL MASTITIS SAMPLES
E COLI
100%
90%
80%
70%
60%
50%
40%
Intermediate
30%
Sensitive
20%
10%
0%
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Resistant
Mastitis in the Australian dairy industry
CLINICAL MASTITIS SAMPLES
STREP DYSGALACTIAE
100%
90%
80%
70%
60%
50%
40%
Resistant
30%
Intermediate
20%
Sensitive
10%
0%
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Mastitis in the Australian dairy industry
SUBCLINICAL MASTITIS SAMPLES
STAPH AUREUS
100%
95%
90%
85%
Resistant
Intermediate
80%
75%
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Mastitis in the Australian dairy industry
Sensitive
SUBCLINICAL MASTITIS SAMPLES
STREP UBERIS
100%
99%
98%
97%
96%
95%
94%
Resistant
93%
Intermediate
92%
Sensitive
91%
90%
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Mastitis in the Australian dairy industry
SUBCLINICAL MASTITIS SAMPLES
STREP DYSGALACTIAE
100%
90%
80%
70%
60%
50%
40%
Resistant
30%
Intermediate
20%
Sensitive
10%
0%
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Mastitis in the Australian dairy industry
SUBCLINICAL MASTITIS SAMPLES
CLOXACILLIN SENSITIVITY
100%
90%
80%
70%
60%
50%
40%
30%
20%
10%
0%
Resistant
Sensitive
40
Staphylococcus aureus
0
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Mastitis in the Australian dairy industry
Streptococcus
dysgalactiae
0
31
Streptococcus uberis
0
138
CONCLUSION
SUMMARY
A RESULT THE DAIRY INDUSTRY CAN BE PROUD OF
• Cloxacillin has been the most commonly used antibiotic in Australia for treating mastitis
over a 35 year period
• The Staphs and Streps responsible for the clinical cases of mastitis in this survey were all
still 100% sensitive to this antibiotic – a remarkable result given the time this antibiotic
has been used
• Australian vets and producers can confidently say they have been using antibiotics
responsibly
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Mastitis in the Australian dairy industry
THE FUTURE
THE BACTERIA CAUSING MASTITIS IN OUR HERD IN 2013 ARE STILL HIGHLY
SENSITIVE TO THE ANTIBIOTICS WE CURRENTLY HAVE REGISTERED IN
AUSTRALIA
• Producers may need to take more care in the application of these antibiotics to improve
cure rates – focus on hygiene, administration technique and ensure 100% compliance
with full course of treatment
• The industry may need to investigate new ways of using existing antibiotics to achieve
higher cure rates, for example:
– Extended treatment strategies
– Different formulations
• Earlier detection of clinical mastitis and prompt treatment strategies may also enhance
the effectiveness of the antibiotic arsenal
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Mastitis in the Australian dairy industry