Martin Green School of Veterinary Medicine and Science · Mastitis in dairy cows: Research to...

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