National Farm - Level Mink Biosecurity Standard - Producers' Guide
Section 2: Animal Health Management
Animal Introduction, Movement and Removal

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2.1 New Animals – Buy Clean

Many diseases, including ringworm, Aleutian disease, and even genetic diseases such as hereditary tyrosinemia can be brought onto a farm. The purchase of diseased and subclinically infected mink is one of the most significant methods of disease introduction.

Purchase breeding replacements or new genetic stock only from reputable breeders who disclose all potential health problems and who follow and document current science-based Aleutian disease control/eradication programs. Ideally, these programs would be developed collaboratively by industry and veterinary specialists (private practitioners and academia) and implemented at an industry level.

2.1.1 Target Outcome

Obtain new breeding stock from reputable breeders with healthy herds; verify herd health and, when warranted, treat new breeding stock with booster vaccinations and for other health issues such as injury during transport and parasites.

It should always be an objective to obtain healthy breeding stock from reputable breeders to minimize the possibility of introducing disease pathogens to farms from outside sources.

Diseases that should be of concern include, but are not limited to, Aleutian disease, mink virus enteritis, footpad disease, and hemorrhagic pneumonia (Pseudomonas) infections.

Producers should consider all new mink that are purchased potentially infected, and treating as such, regardless of the reputation and credentials of the seller. The suggested best practices for obtaining new breeding stock are as follows:

  1. Ensure that mink purchases comply with appropriate federal, provincial, state, and other regulations.
  2. Require documentation of health status, such as a veterinary health certification and/or test results, of animals for infectious and genetic diseases prior to purchase.
  3. Test mink for Aleutian disease as appropriate; for example, to prevent Aleutian disease introductions to clean farms.
  4. Ensure vaccinations, and parasite and medical treatment protocols are performed.

2.2 Scheduling Animal Movements

Every time new mink are introduced or resident mink are moved, there is the opportunity to introduce and transmit microbial pathogens by people, animals, birds, equipment, and supplies.

2.2.1 Target Outcome

Limit the frequency of new mink introductions and movements of all mink to reduce opportunities for the transmission of microbial pathogens.

Newly acquired mink pose a significant opportunity for disease introduction, affecting the health of the herd and the microbial pathogen load on the premises. Infected mink can shed microbial pathogens; however, not all infected mink may appear clinically ill, and this can occur

  • early in the course of an illness before clinical signs appear;
  • when the microbial pathogen only causes mild illness; and/or
  • after a mink appears to have clinically recovered from an illness, but may still be shedding pathogens.

Suggested best practices:

  1. Limit the frequency of introductions (purchases) of new animals.
  2. Limit the frequency of on-farm animal movements.
  3. Avoid using the same vehicles for transporting mink and other commodities:
    1. If the same vehicles must be used for transporting mink and other commodities, trucks should be swept clean, and where necessary and weather permitting, washed and disinfected between transporting different commodities. An additional safeguard is to schedule high-risk activities as the last activities, prior to a complete C&D of the vehicles.
    2. Weather permitting, it is recommended that trucks and transportation pens be washed between shipments of live mink and completely cleaned and disinfected, if the delivery of mink has been to other farms or locations. Manure and mink body fluids are a source of microbiological contamination (e.g. Aleutian disease and Salmonella).

2.2.2 Target Outcome

Maximize downtime between mink groups on the premises and in the housing area.

The microbial pathogen load can be reduced in the absence of a host to maintain it. Downtime, leaving pens and sheds empty, allows for the natural reduction in numbers of disease-causing pathogens within the herd/housing area and for appropriate removal of organic material and a thorough cleaning and disinfection process.

The longer a housing area is empty, the less likely it is that disease organisms will remain a threat. Pathogen load can be minimized with the removal of organic material and a thorough cleaning and disinfection process.

To maximize microbial pathogen reduction in pens/sheds, the area that has been emptied should be clearly separated from other housing areas that contain live mink to avoid cross contamination and re-contamination. Although the full turnover of mink on a premises (all in – all out) is unlikely to occur, mink sheds or areas within the shed should be cleaned, disinfected, and left empty for two to three weeks whenever mink are moved.

Suggested best practices:

  1. Schedule an effective downtime period for all sheds to occur at least once a year. Use the longest period of downtime possible; however, a period of two weeks should be considered the minimum.
  2. When determining an appropriate period of downtime, consider the current health status of the mink and other effects, such as the health status of surrounding farms.
  3. Be aware that pelting sheds may be emptied when breeding sheds may not be emptied, and thus cleaning and disinfection may have to occur at different times of the year.
  4. Plan the breeding, pelting, and introduction of new mink to allow parts of the facility to be emptied of animals.
  5. Clean and disinfect the mink sheds whenever the sheds are empty.

2.2.3 Target Outcome

Practise strict biosecurity measures when handling mink.

Mink pens provide a secure environment that can mitigate the contact by mink with infected animals and contaminated people, equipment, and materials. Handling exposes mink to a much broader array of risks – the contamination and microbial pathogens encountered by these people, equipment, materials, and other animals. The pelting process poses a risk for shedding microbial pathogens, and thus care must be taken to ensure breeding animals are not exposed.

Suggested best practices:

  1. During pelting, strict biosecurity practices, including wearing protective clothing, along with cleaning and disinfection, are used to ensure that breeding stock remain disease free and that disease is not spread throughout the premises during the following activities:
    • mink catching
    • pelt processing
    • moving
    • carcass disposal
    • euthanasia
  2. Ideally, all equipment and materials are dedicated to on-farm use, and designed or constructed of materials that allow for easy cleaning and disinfection.
  3. Ensure that the movement of animals, carcasses, fat, pelts, and humans minimizes the opportunity for disease transmission when pelting activities occur off-site.

2.3 Isolation Procedures – Stay Clean

Separating activities by time, carefully planning the procedures, having designated equipment and areas, along with effective biosecurity procedures, are critical to ensuring that isolation procedures are effective.

2.3.1 Target Outcome

Each premises has a sufficient number of pens to physically isolate new mink arrivals from the main herd, and has isolation procedures to minimize the transmission of microbial pathogens.

Many mink diseases can be introduced by the introduction of new animals. Isolation areas are critical to ensuring the health of the mink herd. The isolation period provides an opportunity to determine animal health by observing mink for clinical signs of illness, conducting tests, and administering treatments if warranted. Monitoring the herd from which the animals were acquired during this isolation period provides additional information on potential health risks to which the new mink may have been exposed. Upon completion of the isolation period, the newly purchased animals may enter the main herd when they meet the established herd health criteria.

Suggested best practices:

  1. Isolate all new mink arrivals for a period of at least three weeks, observing for signs of illness or other health issues.
  2. Perform multiple Aleutian disease tests for all new mink prior to introduction to the main herd.
  3. Practice strict isolation procedures, including boot and clothing changes and hand sanitation, to ensure potential diseases are not transferred from the isolated animals to the main herd.
  4. Dedicate separate equipment, which is specific to the isolation facilities.
  5. Feed and handle mink in isolation facilities at the end of the day (separating activities in time).
  6. Near the end of the isolation period, contact the producer from whom the new animals were acquired to determine whether an infectious disease has occurred in that herd.

Animal Health Management Key Points: Animal Introduction, Movements, and Removal

Buy Clean and Stay Clean
  1. Ensure new mink are healthy by sourcing from reputable suppliers that apply and document sound medical and biosecurity practices in their herds.
  2. Reduce the opportunity for disease introduction by limiting the frequency of mink introductions and movements.
  3. Maximize downtime on the site and between mink groups.
  4. Practise strict biosecurity when handling, catching, and moving mink.
  5. Ensure all sites have a sufficient number of pens to isolate new mink.
  6. Apply isolation procedures for all new mink arrivals, whether newly purchased or moved between producer-owned farms.

Monitoring and Maintaining Animal Health and Disease Response

Knowing the disease status of the herd is critical to recognizing whether an important disease condition is present on the farm and in initiating a prompt and effective response. Early diagnosis and disease surveillance help to contain the microbial pathogen in the event of an infectious or reportable animal Mink ID disease (Reportable disease).

Suggested best practices for monitoring herd health:

  • Observe animals regularly.
  • Maintain a record of losses and illnesses.
  • Recognize suspicious clinical signs that might suggest a contagious disease problem.
  • Recognize unacceptable mortality rates or an abnormal pattern of mortalities.

Once these indicators of contagious disease are recognized, undertake immediate action to diagnose the disease and activate a response.

2.4 Animal Health Monitoring and Maintenance

2.4.1 Target Outcome

Individuals who monitor animal health are knowledgeable in mink health, in recognizing disease symptoms, and in response protocols.

Essential for effective disease monitoring and response protocols is having the knowledge and experience in identifying ill health in mink, including changes in appearance, behaviour, and activity. Staff members are not expected to diagnose the disease – this is the responsibility of the herd veterinarian and veterinary diagnostic laboratories. Staff, however, should know when something is wrong and what response protocols to follow.

Suggested best practices:

  1. Train staff to detect ill health in the mink herd, and implement response protocols.
  2. Ensure written disease response materials are readily available to staff.

2.4.2 Target Outcome

Daily procedures for animal health monitoring are followed and records of vaccination, illness, treatments, and mortalities are maintained.

Many factors may negatively affect animal health. These include, but are not limited to, infectious diseases, genetic diseases, management practices, and climatic conditions. To protect mink health and welfare, early detection of infectious disease is critical in preventing the spread of microbial pathogens. It allows for an appropriate response, reduces the extent and severity of a disease outbreak, and minimizes contamination of the premises.

Daily animal health monitoring provides the ability to promptly identify, investigate, and resolve health and management problems. Animal health records provide more accurate data than relying on memory and enhance the ability to identify disease trends, review previous health issues, and determine the success/failure of treatments and herd health programs.

Suggested best practices:

  1. Examine mink at least daily for any evidence of poor health; signs may include reduced feed and/or water intake, lethargy, eye condition (e.g. discharge, inflammation), stool (e.g. colour, form)
  2. Isolate sheds for mink that are showing signs of disease.
  3. Have separate staff, where feasible, to examine mink in isolation after the examination of the main herd; staff examining mink in isolation should wear outerwear, boots, and gloves that are dedicated to the isolation area.
  4. Ensure that staff wash their hands when leaving the isolation area.
  5. Maintain records of illnesses, behaviour changes, daily mortalities, and treatments.
    Sample: Mortality Record
    Date Shed # Pen or Mink ID Samples Taken for Determination of Cause of Death (Y/N) Cause of Death Action Taken
    Sample: Pen or Individual Treatment Record
    Date Shed # Pen or Mink ID Number of Mink Product Name Reason the Product was Used Dosage and Route Used The Person Who Administered Treatment Weight of Treated Mink Treatment Result
  6. Carry out and record birth counts, and monitor regularly to assess and respond to disease or management issues that affect kits.

2.4.3 Target Outcome

Animal health monitoring increases following the addition of new mink, illness in the herd, or industry disease alerts.

The frequency of animal health monitoring must be increased when there is a heightened risk of disease transmission. Stressed animals are often more susceptible to disease and frequently shed higher levels of microbial pathogens.

Suggested best practices:

  1. Increase the frequency of disease monitoring after higher-risk activities, following any activities which stress animals, when sick mink have been identified, or when industry has reported a disease alert.

2.4.4 Target Outcome

The detection of ill health in the herd results in an appropriate response.

Suggested best practices:

  1. Appropriate responses to evidence of disease may include animal isolation until the resolution of illness and infectivity, treatment, culling, euthanasia, or other interventions.
  2. Ideally, avoid using sheds and pens where sick or dead mink have been located until the cause of illness or death is known.
  3. Avoid using sheds and pens for other mink that previously housed sick or dead mink until careful cleaning and disinfection has been carried out.
  4. Never spread unconsumed feed from the pens of sick or dead mink to other pens.
  5. Postpone using transportation pens for moving sick mink until cleaning and disinfection is performed.
  6. Contact your veterinary advisor, and arrange to have sick or dead mink sent to a laboratory for autopsy and analysis.

2.4.5 Target Outcome

Each farm establishes and implements a herd health program, in consultation with a veterinarian.

Determining the cause of disease facilitates control and treatment plans, increasing their effectiveness and reducing expenses.

Veterinarians receive extensive training in many disciplines, including, but not limited to, disease identification, the appropriate methods of sample collection, and submission to a veterinary diagnostic laboratory.

With veterinary input, establish and follow a comprehensive mink herd health program. The program should include the following:

  1. periodic visits (4 times a year) by the veterinarian to view the herd and provide an opinion on health status;
  2. information on mink herd health that should be kept and made available to the veterinarian during visits or when disease is suspected or identified;
  3. inspection and review of biosecurity protocols, systems, and activities during the veterinarian visit;
  4. vaccination and treatment program; and
  5. breeding and weaning strategies.

Vaccines are available to protect mink against some important diseases, though they do not provide complete protection to the herd. Some vaccines are capable of preventing clinical disease, whereas others reduce the severity or extent of a disease, but none provide full herd protection against a disease outbreak.

Vaccination of ill or compromised animals can reduce the efficacy of the response to vaccination.

Depending on the animal health status, vaccinated animals require at least three weeks to develop protective immunity. Vaccinating new mink just prior to their addition to the herd is ineffective. Mink farmers should carefully review their vaccination policies with their veterinarian to optimize protection for the herd. Suggested best practices:

  1. Develop the vaccination program with your veterinarian at least a year in advance to ensure that adequate vaccine is ordered to protect mink the following year.
  2. Customize the vaccination program for your farm, based on management practices, disease history of the farm, and the surrounding area.
  3. Ensure that staff members are familiar and follow the manufacturer's directions for the proper storage, handling, and administration of vaccines.

Establishing a Medication Usage Plan

The purchase of healthy stock and the implementation of biosecurity and vaccination programs will reduce the need for antibiotics, as well as the cost of production. Producers, with their veterinarians, should review the protocols they have in place at least once per year. Establishing protocols and keeping records takes time; however, the process establishes a means of ensuring their effectiveness and is a necessary part of the production program.

Mink production is full of change – new employees, new disease diagnosis by the veterinarian, and new products. Protocols inform a new employee on the rationale for using a medication, the type of mink on which it is used, the dosage to be used, and the way it is administered. Records should show when the veterinarian reached the diagnosis and when the protocol was changed. Written procedures allow other staff to take over during the absence of those who normally carry out the task.

Establish a Medication and Vaccine Usage Plan with your veterinarian. Review the plan annually. Obtain a prescription from a veterinarian for the use of medications or vaccines for the mink herd, and keep the prescription on file. Also, annually, or as warranted, review the Medication and Vaccine Usage Plan with your staff, ensuring that it is being followed.

Create a plan that identifies what actions to take if an error were to occur in medication use, including feed medications. This plan provides:

  • a description of how to identify affected animals,
  • what records to keep concerning the incident and the actions taken to correct the problem, and
  • who to contact regarding the incident.

The improper use of antimicrobials, whether administered by injection, in the water or in the feed, could lead to antimicrobial resistance; to minimize the impact of this, review your Medication and Vaccine Usage Plan to ensure that all antimicrobials are used appropriately.

All prescription medications are marked with a Pr symbol on the label. These products may be purchased only from veterinarians with whom you have a veterinary-client relationship. Over-the-counter (OTC) medications do not have the Pr symbol but will be marked For Veterinary Use Only and can only be administered to animals. These medications may be purchased from veterinary clinics or other livestock medicine outlets.

Repackaged product (repackaged by your veterinarian) must be labelled appropriately and must only be provided under a valid veterinary prescription. Be aware that when materials are repackaged, there is a risk of contamination, and they must be handled with care.

If your veterinarian supplies you with a generalized drug use plan that has been developed for other clients, highlight the products that you use, or transfer the information on the products you use to your own personalized drug use plan.

Read and follow the information contained on medication labels and inserts. Pharmaceutical companies periodically make changes to dosage rates or withdrawal times. Checking labels allows you to identify when changes are made.

Establish identification procedures for animals that receive treatment by all administration routes (e.g. in the feed, in the water, by injection and topical application). Identifying individual animals and pens is important, as many drugs require treatment to be repeated over several days.

Sample: Medication and Vaccine Usage Plan
Date Shed # Product Name Manufacturer Medication/ Vaccine Used For Dosage Administration Route Used Product Warnings Storage Location On-Farm

2.4.6 Target Outcome

Escaped and released farmed mink and wild mink that are captured are not permitted entry into the farm site.

Mink that have either escaped or been released from the farm site can be directly exposed to microbial pathogens through contact with wild mink, mink from other farms and wildlife, and/or indirectly exposed through contact with a contaminated environment. These mink, if caught, should not be brought back onto the farm due to the risk of transmitting microbial pathogens to the remaining herd.

Wild mink that are inadvertently caught and returned to a mink farm pose a similar health risk. They should be dispatched according to applicable federal, provincial, and municipal government regulations.

When there is a substantial escape or release of mink from a farm, capture and re-entry to the herd may be considered. The herd health status will be compromised, and a plan will be needed to establish the health of the mink, returning the farm to a biosecure status.

Suggested best practices:

  1. Ensure that staff members are familiar with protocols for dealing with escaped mink.
  2. Do not return any mink that escape from the shed to the herd.
  3. Euthanize escaped mink and dispose of the carcass in a biosecure manner, according to applicable federal, provincial, and municipal government regulations.
  4. If mink are not euthanized but are held until pelt harvest, isolate from the herd, and manage following protocols for sick and/or contagious mink.
  5. For a substantial escape or release of mink where the animals are returned to the farm, follow a program of testing that is developed in cooperation with the consulting veterinarian to ensure that herd health status has not been compromised. Where herd health status has been compromised through the introduction of disease, institute a program to return the herd to a biosecure status that may include
    1. regular testing for Aleutian disease and increased monitoring for signs of illness,
    2. booster vaccinations, and
    3. replacement of the complete herd with new mink breeders.

2.5 Animal Health Response

2.5.1 Target Outcome

The recognition of unusual clinical signs, clinical signs consistent with serious infectious diseases, and/or high mortality rates trigger a response that includes farm lockdown and seeking a diagnosis.

To mitigate the risk of transmitting disease pathogens from a potentially infected premises to other mink farms in the area, immediately implement a farm lockdown.

Trigger points to consider:

  • the recognition of unusual clinical signs in the mink;
  • illness in the mink herd beyond normal levels and normal variance – good health records allow producers to determine average values (and the degree to which it varies) for illness in the herd at different stages of production; and
  • increased mortality in the mink herd beyond normal levels and normal variance – as per illness, when mortality varies beyond normal levels and normal variance.

Some of the trigger points will be consistent across all mink farms (certain clinical signs of illness in mink), whereas others (the average number of sick or dead mink) will vary slightly, based on a producer's production practices. Therefore, it is best for producers, in consultation with their veterinarian, to set trigger points for percent mortality and illness for their own herds.

When trigger points are reached, implement immediate steps to minimize the risk of spreading microbial pathogens within the farm or to other farms.

The elements of a farm lockdown include the following:

  • preventing entry to the farm of all non-essential personnel;
  • notifying industry members, neighbours, organizations, and authorities about the issue;
  • instituting enhanced biosecurity measures for feed and other necessary input deliveries;
  • restricting the movement of people, animals, equipment, vehicles, and other materials off the farm; and
  • seeking a diagnosis.

Suggested best practice disease response activities:

  1. Contact your veterinarian.
  2. Implement a self-imposed premises lockdown to prevent disease spread beyond the farm.
  3. Self declaration and immediate notification of:
    1. neighbours, so they are aware of the disease outbreak and can take steps to protect their farms;
    2. feed kitchens and/or feed input suppliers, so they can take precautionary steps, such as delivering feed to the infected farm at the end of the day;
    3. provincial and national industry organizations; and
    4. provincial and/or federal governments where regulations are in place regarding reportable diseases.
  4. Identify the biosecurity procedures that are necessary to avoid spreading microbial pathogen infection beyond the farm when delivering feed ingredients, feed, and other inputs to the infected premises.
  5. Submit samples for analysis and disease diagnosis.

Animal Health Management Key Points: Animal Health Monitoring and Response

  1. Know the clinical signs of poor health in mink and the appropriate disease response measures.
  2. Monitor animal health, and maintain records at least daily.
  3. Maintain a daily mortality log, and perform regular monitoring of all mink.
  4. Increase animal health monitoring during periods of increased disease risk.
  5. Obtain the advice of veterinarians on implementing a herd health program.
  6. Do not allow escaped mink to re-enter the farm premises.
  7. Implement enhanced biosecurity to prevent the spread of a disease when unusual clinical signs or high mortality is observed.
  8. Lockdown the premises by restricting deliveries, shipments, and the movements of animals, equipment, vehicles and people; and by notifying industry suppliers and neighbours.
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