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The disease is spread when calves ingest material contaminated with the MAP bacterium. Infection typically happens in the first few months of life. The main source of MAP on the farm is manure of mature infected animals. These cows seed the environment with the MAP bacterium directly through their feces. MAP is very hardy and survives heat, cold and drying for one year or longer. Calves come in contact with this manure through fecal contamination of feed or water. Infected dams can also be a source of MAP for calves through their colostrum and milk, or if the calf nurses a manure contaminated teat.For uninfected herds the main risk for introduction of the disease is the purchase of infected animals.
Because of the slowly progressive nature of the disease, cattle can be infected for years before exhibiting clinical signs. Some infected animals may never exhibit clinical signs in their normal productive life times. While cattle exhibiting clinical signs shed the highest numbers of MAP, most infected animals will shed large numbers of MAP sporadically in their manure for months or years. The result is a “Tip of the Iceberg” phenomenon, where many animals in a herd can be infected with few or any showing clinical signs: One infected cow showing clinical signs can indicate 1-2 more cows sick, but not yet obvious (clinical), 6-8 cows infected, but not yet sick (sub clinical) and 10 to 15 infected calves and young stock that may develop the disease later on in life.The three common ways to test a herd for Johne's disease are: culture of fecal samples (individual or pooled; collected directly from the animal or the barn or pasture) to isolate MAP, direct PCR with the same type of samples to detect MAP DNA, and blood, or tests on blood or milk samples for antibodies by the animal in response to MAP infection.
Johne’s disease has been in the dairy industry press a great deal over that last number of years and especially as other provinces began to move forward with individual education and control programs. In the past, Atlantic Canada has had strong participation both in researching Johne’s disease and developing a Voluntary National Control Program. However, it is time to move forward, on a regional basis with a Johne’s disease education and control initiative specifically for Atlantic Canada. A forum of industry leaders was organized with the goal of assessing other programs in Canada and exploring the development of a program for Atlantic Canada.The forum identified 4 reasons the industry needs to act with a control program.
Herd testing will be conducted using culture of the bacterium, Mycobacterium avium paratuberculosis (MAP), from comingled manure sources in the dairy barn. This procedure, known as environmental culture (EC), determines, without risk of false positive results (100% specificity), the status of the herd. In other words, if the bacterium grows from the samples that are collected, we can be 100% certain that that MAP is present on the farm. This method has distinct advantages over herd assessment with immune tests (such as milk ELISA), where there is a risk that a false positive test can occur, mistakenly labelling a negative herd as infected. Both EC and individual animal ELISA testing have a slight risk of calling a herd with a small proportion of infected cows test negativeEnvironmental culture will be conducted using strict collection protocols based on the USDA recommended procedures. Six mixed manure samples will be collected from the prescribed locations by project personnel. Culture will be conducted at the Maritime Quality Milk Johne's research laboratory at the Atlantic Veterinary College.All samples are collected by project personnel to insure consistency. Laboratory results will be confidential and provided only to the designated AJDI certified veterinarian for interpretation and communication to the producer
National Reference Centre for Mycobacteriology in Manitoba
3.4 Non-saleable milk is never fed to calves1.1 Visitors do not have access to the cattle or are required to wear clean footwear and clothing2.5 No calves are born outside the designated calving area/pen3.3 Calves are fed milk replacer or pasteurized milk only2.4 The calving area is never, ever, used by non-calving cows3.5 Calf housing and feeding is remote from cows, cow manure and any cow movement areas3.6 Mixing utensils and feed/water buckets are visibly clean and all are washed daily with soap and disinfectant
Web dairy focus 2012x
Oh Crap! More on Johne’s Dr. Greg KeefeDr. Shawn McKenna, AJDI Steering Committee, AJDI Scientific Committee, Norman Wiebe and Dr. Karen MacDonald-Phillips
Outline Reacquainting with Johne’s Other programs Atlantic Johne’s Disease Initiative Results to date Take home and a challenge
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
Transmission of Infection Ingest material contaminated with MAP Young Calves Manure of mature infected cow Colostrum and milk MAP is hardy Uninfected Herds Purchase of infected cow
Diagnosis Tip of the Iceberg Effect Clinical Cow Subclinical Cows Infected Calves
Calf Heifer Infected cow Clinical cow High risk of Incubating May shed Shedding infection Low risk of No overt signs Chronic weightFecal oral infection infection/shed loss Lower production Colostrum risk No overt signs DiarrheaNo outward signs Lower production Median age between infection and shedding is 5 years Most animals get culled for low production before clinical
Why Johne’s Economics Decreased milk production Culling and reproUK study Sibley, Orpin, Pearce (ICP 2012) Mean 305 day yield (Kg) Calving to conceptionWhole herd current lactation 10,203 106Whole herd previous lactation 10,130 102Test positive in current lactation 9,424 136 For 3rd lactation predicted production was 10,059 Kg and actual was 8,562 Kg Cattle movement Infection reservoir cows Movement = spread Market access Competitive advantage for local genetics
Dutch Quality Assurance Initiated in 2006 Initial categorization by milk ELISA Negative test every other year “A” status Positive test annually Cull positives = “B” Retain positives = “C” Mandatory 2010 – Mandatory “B” 2011 Allow culture confirmation of positives 50% of “B” become “A” with culture Driven by processors (and $ support)
UK System Modular biosecurity program Myhealthyherd.com Risk management based BVD, IBR, Leptospirosis, TB, Bluetongue, Johne’s and Neospora Johne’s module uses Danish system 2500 herds enrolled (25%)
Program Structure - all programs Voluntary 4 Key Components: Education – All 4 programs – Most Important! Risk Assessment & Management Plan Testing – Different approaches Research – All 4 programs – variable funding
Quebec Pre- program: (2007-08) Continuing education (75% of all AMVPQ) Client awareness (conference and publications) Laboratory testing capacity and expertise Prevention (2008-present) Risk assessment (Y 1) Environmental cultures (Y 2) Individual animal testing Only if farmer agrees to not sell/move positives Affidavit/ATQ
Ontario 4 KEY Components: Education of Dairy Producers, Veterinarians and Consumers Risk Assessment on EVERY dairy farm ANNUALLY….goal Optional Testing of entire milking herd (funded ONCE) over 4 years of program PERMANENT Removal of ALL HIGH positive cows
Herd Categorization Environmental Culture (EC) EC (-) versus EC (+) USDA-based protocol 6 sites of well mixed manure Very prescriptive methodology Norman Wiebe Third party collection of samples Coordinator Why Environmental Culture? No risk of false positives Herd sensitivity high Will not find all positive herds – no test will
100 80 60 Ability of EC to detect herds at different prevalence rates Good when over 2% 40 Excellent once over 5% 20 0 0 5 10 15 Within Herd Test Prevalence (Fecal Culture) Sensitivity CI_low CI_highEC Se 71.4% (49.2%-86.5%) Courtesy of Carrie LaversWhen prevalence ≥5%, Se ≥90%Cow Fecal Culture Se 19-53%
Risk Assessment & Management Plan (RA & MP = RAMP) Cornerstone of ALL Johne’s Programs Conducted only by AJDI certified vets Separate RA for EC (+) and EC(-) Herds Emphasis on external versus internal biosecurity Includes a Management Plan Individualized Best management practices Individual Cow Testing EC (+)
Minnesota data Fecal culture Serum ELISA Impact of risk management overEspejo et al., ICP 2012 time on new infections in heifers
Register of EC Negative Herds Biosecurity - goal no animal transfers Total Voluntary Two Level Program EC negative level 1 (Entry) All 6 samples negative Must re-test in 10-14 months EC Negative level 2 (Maintenance) All 6 samples negative Must re-test every other year Loss of EC Negative Status: a) Any positive samples b) Re-test not on schedule
Project status Outputs to Date Enrollment of Herds Sampling and Diagnostics RAMP Recommendations
Enrollment in the AJDI 1st Year Goal: 50% of Atlantic Canada’s herds Target of 347 herds 364 herds enrolled as of March 24 160.0% 140.0% 120.0% 100.0% 80.0% 141.9% 60.0% 106.9% 105.1% 105.1% 97.7% 40.0% 20.0% 0.0% NB NS PE NL Total Enrolment as a percent of initial goal
Project OutcomesValue Number PercentTotal Herds Enrolled 364 herds 105% of goal (53% of herds)Total Herds Sampled 251 herds 69% of enrolledTotal Herds Diagnosed 195 herds 78% of sampledTotal EC (+) 39 herds 20% of diagnosedTotal RAMPS Received 108 herds 55% of diagnosed
RAMP Recommendations Max 3 Recommendations per RAMP Rank in order of importance Producer and vet must agree and sign MPRecommendation Freq. Rank 1 Rank 2 Rank 3Animals are not purchased (closed herd) 62 37 12 13>90% of calves removed <30 minutes 57 27 18 12Colostrum and milk bottle/bucket fed 33 16 14 3Non-saleable milk never fed to calves 21 6 6 9No visitors or require clean clothing 21 4 9 8Feed milk replacer/pasteurized milk 15 4 4 7Calves born in designated calving area 14 5 6 3No non-calving cows in calving area 13 3 7 3Calf areas remote from cows/cow manure 9 2 4 3Never more than a single cow in the 8 4 3 1calving pen/area
Between herd biosecurity1.3 Did you purchase animals in the last 5 years 30 Yes, from multiple herds 20 Yes, from two or less herds of unknown status 7 Yes, from two or less herds of known negative herd status 1 No animals have been purchased in the last 5 yearsComment: The introduction of infected animals from other infected herds is the way JD moves from herd to herd.Introducing animals from multiple herds is associated with both an increased risk of introducing MAP, as well as withhaving a higher percentage of the herd being test positive. If animals need to be purchased, buy from low risk herds (herds with a testing history). Tests of individual animals prior to purchase do not provide evidence of the infection status of that individual.
Calving pen and preweaning2.7 What is the duration of exposure of the newborn calf to the cow? 10 Less that 10% of calves are removed from the dam within 30 minutes 7 Between 10 and 50% of calves are removed from the dam within 30 minutes 4 Between 50 and 90% of calves are removed from the dam within 30 minutes 1 More than 90% of calves are removed from the dam within 30 minutes3.2 What is the source of colostrum fed to calves? 10 Calves are fed pooled colostrum or colostrum from multiple cows 5 Calves are fed colostrum from a cow other than their dam 1 ALL calves are fed colostrum only from their mother or a single low risk donor cowComment: Colostrum can be a source of infection for calves if there are undetected shedding animals in the herd.For negative or low prevalence herds (environmental culture negative), the most practical risk control is to fed colostrumfrom one cow to one calf. Testing of the status of donor cows or dams should be within the last year.
Take home Johne’s is a worldwide issue Production, reproduction, culling Developed dairy countries have programs Testing is challenging but control of spread is understood Atlantic Canada has launched a very successful initiative Risk-based (between and within herd) Minimal testing
Last Call Funding allows for enrolment of 60% of herds Currently at 53% If you are on the fence now is the time to step up!