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The Program

The Atlantic Johne´s Disease Initiative (AJDI) program is fully voluntary. The program provides substantial resources to assist herds that have the disease to decrease spread and overall prevalence on the farm. Additionally, environmental-culture test-negative herds are provided with management plans to maintain their status. Like all other dairy biosecurity program, AJDI discourages the movement of animals between farms. When animal transfers are necessary, the AJDI program promotes informed animal movement by providing an accessible register of environmental-culture test-negative herds. ADJI promotes herd of origin testing.

The program is funded for three years (2015-2018) and includes two main activities; herd testing and risk assessments. These procedures are designed to strategically, and in a cost-efficient manner, reduce the impact of Johne´s disease on the regional dairy industry by decreasing existing infections and reducing new infection.

Herd Testing

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 negative.

Environmental 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. The laboratory has successfully completed the annual USDA proficiency test for Johne´s culture for several years. An on-line form to request testing is available by following the link.

Herds positive on EC will be eligible to participate in voluntary individual animal testing (see below). Herds that are EC test negative will be eligible to be listed on a register of EC test negative herds should they voluntarily chose to do so (see below).

Herds will be eligible to be tested annually. For herds with two consecutive negative EC tests, testing eligibility will switch to every second year.

The program will cover all costs (sample collection, transportation and culture) for the herd EC. Click here for details.

Herd Risk Assessment

Because of the pathway of infection (from mature animal to susceptible calf) and the challenges with accurately identifying carrier animals, risk assessment and subsequent management plans are the fastest and most cost-effective way to reduce the effects of the disease. As an added bonus, many of the management procedures will reduce other calfhood diseases.

When herd testing results are available, these results will be given to the AJDI certified veterinarian identified by the herd owner. Only veterinarians that have completed a specific advanced education program, mandated by the AJDI, will be eligible to receive test results for interpretation and communication to the producer. A list of certified veterinarians is available on this website. These program certified veterinarians will conduct a farm-specific risk assessment (usually takes about 1 hour) using the program risk assessment guide at a farm-site visit. Using the knowledge of the herd status (EC) and the farm-specific risk assessment, the certified veterinarian will complete a written management plan for Johne’s disease control for the farm. Risk assessments and management plans will be filed with the AJDI. Risk assessments must be completed for each year that EC is conducted.

The program will cover a portion of the veterinary fees to complete the risk assessment and management plan. Click here for details.

Cow Testing

Cow testing will be available for herds through their veterinarian. Test methods are approved by the AJDI Scientific Committee. Test results will be held in confidence and provided only to program certified veterinarian identified by the herd owner for interpretation and communication to the producer.

Environmental culture status register (For EC negative herds)

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. Environmental culture negative herds may chose to voluntarily participate on the AJDI status register. The program will not disclose the status of any herd without consent. There is no requirement under the program for EC test negative herds to participate in the register. To maintain simplicity and a focus on risk management, there are only 2 levels in the program.

EC Negative Level 1 (Entry)

Herds enter as EC Negative Level 1 if their most recent environmental culture is negative on all six samples. If a previous EC test was positive for that farm, a minimum of 10 month must elapse before a valid retest.

EC Negative Level 2 (Maintenance of status)

Level 1 herds must retest with 10-24 months. If the retest is negative for all 6 samples, the herd is listed as an EC Negative Level 2. Once a herd achieves level 2 status, they must retest no earlier than 10 months and no later than 26 months after the previous test to maintain their status.

Promotion of status

EC negative herds will be eligible to have their status registered on the AJDI website. Only herds currently registered on the AJDI website can use their AJDI status in promotional materials. The register will contain the following material: Herd name, Owner and address, status level, date that the current status level was first achieved, date of most recent test, date that the status level expires. Being listed on the register does not guarantee that the herd is free of the MAP (Mycobacterium avium paratuberculosis) bacterium. With currently available tests, no program can certify a farm as MAP free. The register lists farms for which MAP was not detected in the environment on the day of testing, using standard procedures. The longer a farm maintains environmental culture negative status, the lower the risk a substantial proportion of cows in that herd are infected with MAP

Loss of status

Herds will lose their status level and be removed from the website list if:

  • a) any EC samples are positive on the most recent test, or
  • b) more than 24 months has elapsed for EC Negative Level 1 herds and they have not retested, or
  • c) more than 26 months has elapsed for EC Negative Level 2 herds and they have not retested.
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