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Mastitis in dairy cows:
Research to national control scheme
Martin Green School of Veterinary Medicine and Science
What is mastitis?
Mastitis…
Inflammation of the mammary gland…
…any disease which
causes an immune response and inflammation of mammary tissue
Teat Sinus
Gland Sinus
Gland Parenchyma
Udder Skin
Teat Canal
Teat Wall
Causes of mastitis
All can cause “mastitis” Bacteria Viruses Fungi Physical e.g. trauma Toxins Neoplasia
Clinical Signs
Changes to the milk
Inflammation of the gland – Swollen – Hot – Hard – Painful – Pos necrosis of the quarter
Clinical Signs
Sometimes very sick… – Reduced yield – Temperature drop – Vascular collapse – Death
Why is mastitis important?
• Common (worldwide)…
• Serious repercussions…
Common…
• Clinical mastitis
0
50
100
150
200
250
300
350
Farm in ascending order of incidence rate
Inci
denc
e ra
te o
f clin
ical
mas
titis
(c
ases
per
100
cow
s / y
ear)
>50 cases/100 cows/yr
• Subclinical mastitis
~25% cows infected at any one time
Repercussions…
• Cost – 40% direct costs of common diseases
– £200M UK (US$2.0B )
• Public health – Bacteria in milk
– Antibiotic use
• Welfare – Farm animal welfare council
• Sustainability – Wastage, costs, environmental impact…
My Journey
Control of mastitis
Prevent infections
Reduce pathogen transmission
Between cows (milking)
Environment to cow
Management interventions
Vaccines may come but difficult to date…
Initial studies on control…coincidence
• Environmental causes serious problem
Dry period
10 Months 2 Months
Simple dry period study
End1990s in 6 Somerset dairy herds…
New Infections during the Dry Period
Do these dry period infections cause mastitis?
Bacteria
Strains of E coli
DNA Fingerprinting - Cow 312 B (RH)
2 2 C M1 M2 M3 E coli.
Isolates: 2 weeks pre-calving
Calving
Mastitis: Week 8
Week 9
Week 10
DNA Fingerprinting - Cow 744 B (RH)
M 4 3 2 1 M1 M2 M3 E. coli
Isolates: 4 weeks pre-calving
2 weeks pre-calving
1 weeks pre-calving
Mastitis: Week 1
Week 7
Week 10
DNA Fingerprinting - Cow 167 S (LH)
M 2 1 M E. coli
Isolates: 2 weeks pre-calving
1 weeks pre-calving
Mastitis: Week 2
Changing behaviour of environmental bacteria
M -26-12-5 2 41 62 83 -15 -8 -3 2 -1 0 1 -1 0 1 -1 77 -6 3 M
M -2 0 1 -10 0 56 62 68 -1 0 72 -13 14-13 14 20 30 -6 1 -2 2 M
Bradley A.J. and Green M.J. (2001) Adaptation of Escherichia coli to the Bovine Mammary Gland. J. Clin. Microbiol. 39;1845-9.
It turned out to be important…
…in some herds…
>50% cows became newly infected during Dry Period
>75% of all mastitis originated in the Dry
Period
Which Herds have Dry Period Problems?
Green M.J., Green L.E., Medley G.F., Schukken Y.H., and Bradley A.J. (2002). Influence of Dry Period Bacterial Intramammary Infection on Clinical Mastitis in Dairy Cows. J. Dairy Sci. 85: 2589-2599.
Mastitis in the first 30 days of Lactation
0.00%
5.00%
10.00%
15.00%
20.00%
25.00%
30.00%
35.00%
40.00%
45.00%
50.00%
Farm-years in Ascending order of Clinical Mastitis Incidence
Inci
denc
e R
ate
of C
linic
al M
astit
is(C
ases
per
Cow
at R
isk)
Research into Industry
…Prevention?
Preventive
Treatments Pathogen, Cow, Farm,
Management
Dry Cow Treatment: A Clinical Trial
• Target therapy towards a specific types of bacteria – Gram negative
• RCT - using a targeted product – Found a 50% reduction in clinical gram
negative mastitis
• Confirmed that preventing DP infections does reduce mastitis after calving
Bradley A.J. and Green M.J. (2001) An investigation of the impact of intramammary antibiotic dry cow therapy on clinical coliform mastitis. J. Dairy Sci. 84 1632-1639
Non-Antibiotic Approaches
• Teat sealant during the dry period – Jon Huxley PhD
• Efficacy was at least as good as a long acting antibiotic
Huxley J.N., Green M.J., Green L.E., and Bradley A.J. (2002). Evaluation of the Efficacy of an Internal Teat Sealer During the Dry Period. J Dairy Sci. 85: 551-561.
65% bismuth sub nitrate in a paraffin base
Follow on research
Preventive
Treatments Pathogen, Cow, Farm,
Management
Determinants of Mastitis arising from the Dry Period
Dry
Period
Decisions
Bacterial Interactions
Further studies
Bacterial communities…
Cow and management factors
• Previous Lactation • Drying Off • Early Dry period • Late Dry Period • Calving Period • Overall herd factors Some ‘simple but effective’ …
Drying Off
Surgical spirit swab before administer dry treatments ↓ risk
Late Dry Period Transition yard area > 1.25m2 per
1000kg annual mean cow milk production ↓ risk
8000kg ~ 10m2
Late Dry Period Pasture grazing policy is:
Graze for 2 weeks then
rest 4 weeks
↓ risk
Farm tool for dry period management
Therefore
• Dry period infections important
• Prevention possible but needed new strategies
• Possible to identify herds with DP problems
Different approach to mastitis control?
Outline of approach
“Diagnosis”
Could
Should
Must
Action Points
Randomised clinical trial
Funded by DairyCo (MDC) 52 herd study – half received new approach
Results
-0.4
-0.35
-0.3
-0.25
-0.2
-0.15
-0.1
-0.05
0
ControlFarms
Compliance< 1/3
Compliance1/3 - 2/3
Compliance>2/3
Proport
ional
Chan
ge
in I
nci
den
ce
Rat
e of
Cow
s Aff
ecte
d
Could this be used on a widespread scale?
“Diagnosis”
Could
Should
Must
Action Points
COMPLIANCE
Pilot study 20 vets selected by their farmers
A National Mastitis Control Scheme
• In October 2008 – nationwide…
• First participants trained to use the DMCP in April 2009
• Changes
– Bespoke software – Supporting materials – A website was developed to support implementation of the
Plan
The DairyCo Mastitis Control Plan
Plan Software
Target number plan participants trained in 3 years
= 150
Target number of farms in first three years
= 750
How is it going?
267
970 (1025)
>15% of British cows are on farms that received the plan
Achieving approx a 10% improvement in mastitis in 1 year.
How is it going?
Profile?
Google ‘DairyCo Mastitis Control Plan’
Page 1
Page 3
Page 10
Page 30!
Profile?
• Support and promotion of the scheme by the major retailers, regional funding bodies and also farmer and veterinary bodies.
A National Mastitis Control Scheme
10-20% improvement pa? …still a way to go…
On-going research…
Host pathogen interactions
Molecular epidemiology (strain
specific infection patterns)
Heifer mastitis – repercussions
Prevention of dry period infections
Pathogen transmission
and the cost of mastitis
Understanding infection patterns to prevent mastitis
Virulence and vaccines
On-going research…
Enhancing decision making for
mastitis control
National Scheme part 2:
Optimising decisions on
disease prevention
Clinical trials
Risk factor studies
Research National control scheme
Acknowledgements
• Andrew Bradley • James Breen, Chris Hudson, Katherine Leach, Laura
Green, Jon Huxley, Aurelien Madouasse • Jamie Leigh, Tracey Coffey, Richard Emes, Jasmeet
Kaler
• Funders
– Wellcome Trust – DairyCo – BBSRC – Leo AH – Bimeda AH – Pfizer AH