Johne’s Control:An Atlantic Canada Success

StoryGreg Keefe DVM MSc MBA

Atlantic Veterinary CollegeUniversity of Prince Edward Island

Overview of Disease Johne’s Disease (Yo-nees), Paratuberculosis

Mycobacterium avium subspecies paratuberculosis (MAP)

Chronic, Infectious Enteritis Milk production losses Premature culling Reduced fertility Diarrhea and emaciation

Photos courtesy of

www.johnes.org

CalfHigh risk of

infection

Fecal oral infection

Colostrum risk

No outward signs

Infected cow

May shed

No overt signs

Lower production

Poor Reproductio

n

HeiferIncubating

Low risk of infection/she

d

No overt signs

Lower production

Clinical cow

Shedding

Chronic weight loss

Diarrhea

Lower production

Median age between infection and shedding is 5 years

Most animals get culled for low production before clinical

All HerdsInfected Herds

Infected Cows

Infectious Cows

Affected Cows

JD research in Atlantic Canada

15 years ago estimated that the prevalence was 17% of herds and about 2.5% of cows Blood test of 30 cows

in each of 90 herds Focus on diagnostic

test evaluation Determined the

limitations of blood or milk testing

20-40% of infectious cows

10-20% of infected cows

Atlantic Johne’s Disease Initiative

December 2009 industry meeting

Economic Loss Decreased milk

production Culling and

reproduction Cattle Movement

Infection reservoir cows Movement = spread

Market Access Competitive advantage

for local genetics

Atlantic Johne’s Disease Initiative

Program Pillars Education Infection control & prevalence

reduction Research

MQM lab is USDA proficiency tested for 5

Johne’s diagnostics

Education

Website (www.atlanticjohnes.ca) Mailings and media 47 certified veterinarians

Delivering 1 on 1 farm specific management plan education to dairy producers

EconomicsAwareness Biosecurity Heifers

Control ProgramHerd Categorization

Environmental Culture (EC)Voluntary

Fully funded

Risk Assessment & Management Plan (RAMP)

Required if herd tested Fully funded

Cow Testing

Voluntary - EC positive herds eligible Partial funding

Herd categorization procedures

Environmental culture (USDA) Manure samples

from 6 sites on farm Cheaper than

testing every cow No immediate cow

data Interpretation of

cow data complex in low prevalence farms

No risk of “false positive”

Whole Herd Milk ELISA (Ontario) DHI milk samples Cow data to cull

very high titre animals

False positive results – culling unnecessarily

Risk that farmers rely on culling rather than “management”

Simulating Johne’s control

Kudahl AB, Ostergaard S, Sørensen JT, Nielsen SS. A stochastic model simulating paratuberculosis in a dairy herd. Prev Vet Med. 2007 Feb 16;78(2):97-117.

AJDI testing goals

Minimize false test results Motivate farmers to take

MANAGEMENT actions Ongoing herd and cow testing

project Focus on low within herd prevalence

herds Dr. Carrie Lavers (PhD)

Herd-level testing

020

4060

8010

0Se

nsiti

vity

at t

he h

erd

leve

l (%

)

0 2 4 6 8 10Within-herd prevalence (%)

Sensitivity (Herd level) 95% Confidence interval

020

4060

8010

0S

ensi

tivity

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C

0 5 10 15Within Herd Test Prevalence (Fecal Culture)

Sensitivity CI_lowCI_high

Environmental CultureSensitivity 71.4%Specificity 98.6% (100%)

Milk ELISA (2% cutoff)Sensitivity 55.7%Specificity 95.8%

Atlantic Johne’s Disease Initiative

NB NL NS PE Total0.00%

10.00%

20.00%

30.00%

40.00%

50.00%

60.00%

70.00%

80.00%

90.00%

60.77%82.76%

71.91% 73.30% 69.28%

Program Launch: June 2011Enrolled 459 unique herds

EC Herd PrevalenceRound 1Total Herds Tested

459Total Herds EC Positive88 (19.2%)1/6 EC Sites Positive23 (5.0%)

2/6 EC Sites Positive 13 (2.8%)

3/6 EC Sites Positive 4 (0.9%)

4/6 EC Sites Positive 7 (1.5%)

5/6 EC Sites Positive 4 (0.9%)

6/6 EC Sites Positive 37 (8.1%)

EC Herd Prevalence

EC Herd PrevalenceRound 2Total Herds Tested

374Total Herds EC Positive84 (22.7%)1/6 EC Sites Positive23 (6.1%)

2/6 EC Sites Positive 9 (2.4%)

3/6 EC Sites Positive 10 (2.7%)

4/6 EC Sites Positive 8 (2.1%)

5/6 EC Sites Positive 6 (1.6%)

6/6 EC Sites Positive 29 (7.8%)

EC Herd Prevalence

Predicting Within Herd Prevalence (Lavers research)

0.0

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With

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erd

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0 .2 .4 .6 .8 1Proportion Of Positive Environmental Cultures

prev plbpub

2/6 positive

6/6 positive

Overall Prevalence

Total herds tested positive over 2 years = 118

Cumulative prevalence = 25.7%

Identified 75% of those in year 1 and 25% only after second round Very close to what would be predicted

from Lavers research !

Benchmarking Atlantic Canada

USDA study 2006 68% of herds positive on single round

Alberta 26% positive in first round Higher rate in year 2

Different collection procedures

Risk Assessment ScoringRisk Assessment Section

Proportion of Maximum Risk Score

EC (-) EC (+)

Section 1: General Johne’s and Biosecurity

0.54 (0.51-0.57) 0.69 (0.63-0.74)

Section 2: Calving Area 0.52 (0.50-0.54) 0.55 (0.51-0.60)

Section 3: Pre-weaned Heifers 0.35 (0.34-0.37) 0.39 (0.36-0.43)

Section 4: Weaned to First Calving Heifers

0.45 (0.42-0.47) 0.50 (0.45-0.54)

Section 5: Dry Cows 0.38 (0.36-0.40) 0.42 (0.39-0.46)

Section 6: Lactating Cows 0.39 (0.37-0.41) 0.44 (0.40-0.48)

Section 1: Management PracticesProportion of Maximum Risk Score

EC (-) EC (+)

Access visitors have to cattle on the farm

0.78 (0.75-0.84) 0.81 (0.72-0.91)

History of clinical Johne’s disease 0.25 (0.22-0.27) 0.63 (0.55-0.71)

History of animal purchases 0.61 (0.56-0.66) 0.78 (0.69-0.87)

Exposure to other farms, animals or manure

0.40 (0.35-0.45) 0.42 (0.34-0.53)

Herd Management Plan

Maximum of 3 Best Management Practices Rank recommendations in order of

priority Agreement between producer and vet

Recommendations for EC Negative Herds Freq. Rank 1

Animals are not purchased (closed herd)

51% 70%

>90% of calves removed <30 minutes

33% 38%

No visitors or require clean clothing 23% 42%

Colostrum and milk bottle/bucket fed cleaning

21% 36%

Non-saleable milk never fed to calves 16% 24%

Recommendations for EC Positive Herds Freq. Rank 1

Animals are not purchased (closed herd)

43% 65%

>90% of calves removed <30 minutes

31% 53%

No more than a single cow in calving area

21% 15%

Feed milk replacer/pasteurized milk 20% 42%

Feed pasteurized/artificial colostrum 18% 45%

Management Plan by EC Result

Why “Success” Exceeded targets for participation

Highest of all voluntary programs Hats off to program vets/industry

steering group!!! Education/extension success

One on one Prevalence moderate

Lower than some regions (opportunity?)

9% of herds have substantial problem Can we build on this successful

model?

Special Thanks Collaborators

Drs Shawn McKenna, Marcelo Chaffer, Carrie Lavers, Emilie Laurin, Karen MacDonald Phillips

AJDI & MQM Staff Art Gennis, Norman Wiebe, MariaVasquez, Natasha

Robinson and Theresa Andrews AJDI Steering Committee

Reint Jan Dykstra, Bloyce Thompson, Phillip Vroegh, Dr. Pauline Duivenrooden , Dr. Frank Schenkels, Richard Van Oord, Doug Thompson, Brian Cameron and Harry Burden

Check out this video

bit.ly/HJhnjv Johne’s Disease in Canadian Dairy

Herds -What is means to farmers By the U of Guelph MAP team –

Steven Roche and Dave Kelton www.atlanticjohnes.ca