Download Slide 1

Johne’s Control:
An Atlantic Canada Success Story
Greg Keefe DVM MSc MBA
Atlantic Veterinary College
University 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
Calf
Heifer
High risk of
infection
Incubating
Fecal oral
infection
Colostrum risk
No outward signs
Low risk of
infection/shed
No overt signs
Lower
production
Infected
cow
Clinical
cow
May shed
Shedding
No overt signs
Chronic weight
loss
Lower
production
Poor
Reproduction
Diarrhea
Lower
production
Median age between infection and shedding is 5
years
Most animals get culled for low production before clinical
All Herds
Infected 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



Cattle Movement



Decreased milk production
Culling and reproduction
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
Awareness
Economics
Biosecurity
Heifers
Control Program
Herd 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)

0
80
60
40
20
5
10
Within Herd Test Prevalence (Fecal Culture)
Sensitivity
CI_high
CI_low
Environmental Culture
Sensitivity 71.4%
Specificity 98.6% (100%)
15
0
0
20
40
60
Sensitivity at the herd level (%)
80
100
100
Herd-level testing
0
2
4
6
Within-herd prevalence (%)
Sensitivity (Herd level)
8
95% Confidence interval
Milk ELISA (2% cutoff)
Sensitivity 55.7%
Specificity 95.8%
10
Atlantic Johne’s Disease Initiative
90.00%
80.00%
70.00%
60.00%
50.00%
82.76%
40.00%
30.00%
60.77%
71.91% 73.30% 69.28%
20.00%
10.00%
0.00%
NB
NL
NS
PE
Total
Program Launch: June 2011
Enrolled 459 unique herds
EC Herd Prevalence
Round 1
1/6 EC Sites Positive
23 (5.0%)
2/6 EC Sites Positive
13 (2.8%)
Total Herds
Tested
459
Total Herds
EC Positive
88 (19.2%)
3/6 EC Sites Positive
4 (0.9%)
4/6 EC Sites Positive
7 (1.5%)
5/6 EC Sites Positive
4 (0.9%)
EC Herd Prevalence
6/6 EC Sites Positive
37 (8.1%)
EC Herd Prevalence
Round 2
1/6 EC Sites Positive
23 (6.1%)
2/6 EC Sites Positive
9 (2.4%)
Total Herds
Tested
374
Total Herds
EC Positive
84 (22.7%)
3/6 EC Sites Positive
10 (2.7%)
4/6 EC Sites Positive
8 (2.1%)
5/6 EC Sites Positive
6 (1.6%)
EC Herd Prevalence
6/6 EC Sites Positive
29 (7.8%)
.15
Predicting Within Herd
Prevalence (Lavers research)
.05
.1
6/6 positive
0
2/6 positive
0
.2
.4
.6
.8
Proportion Of Positive Environmental Cultures
prev
pub
plb
1
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 Scoring
Proportion of Maximum Risk Score
Risk Assessment Section
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)
Proportion of Maximum Risk Score
Section 1: Management Practices
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

Management Plan by EC Result
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%
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


AJDI & MQM Staff


Drs Shawn McKenna, Marcelo Chaffer, Carrie Lavers, Emilie Laurin,
Karen MacDonald Phillips
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