Traffic Control

Examples of disease pathways for African Swine Fever

Source: USDA APHIS African Swine Fever Pathways

Biosecurity is about preventing the transmission of infectious agents that could cause diseases in livestock. Assessing where high risk areas for disease transmission are on a farm and developing standard procedures for sanitation are two critical elements of a solid biosecurity plan. Controlling the flow of traffic on a farm supports preventative measures by keeping carriers of infectious agents away from livestock areas.

Your ability to control who enters the premises, where they drive vehicles or walk into facilities, and how closely they get to livestock areas are important considerations.

  • A visitor to your farm may have come from another farm that experienced a herd infection in some or all of their animals.
  • The visitor interacted with livestock, and then walked through manure and feed being cleaned from the barn where some animals were sick.
  • Their next visit: your farm. Clothing, shoes, vehicle tires, tools, equipment, any pets traveling with them, etc. have the potential to deliver the previous farm's infectious agents within close proximity to your animals.

Visitors should obtain permission or authorization to enter the farm and at a minimum should have clean or disposable footwear. Certain types of animal production facilities where poultry or swine are housed indoors should have more stringent biosecurity measures in place.

Visitors should not be permitted entrance into any animal production facility if they have traveled to a foreign country within the past five days. This prohibition minimizes the risk of introduction of a foreign animal disease-causing agent, which may survive on the soles of footwear.

Important Points to Consider for Biosecurity Traffic Control


  • Establish a line of separation and post signs on the premises so employees and visitors will know about and follow your biosecurity measures.

  • Restrict access to high risk areas. Create "zones" that designate where visitors may or may not enter.

  • Only allow essential workers and vehicles in areas where animals are housed, pastured and fed.

  • Employees should be aware of the possibilities for disease transmission from vehicles and equipment.

  • Farm employees who have livestock at their own home should be required to report to work personally clean and in clean clothes that have not been exposed to their livestock.

  • Use dedicated equipment for manure management.

  • Properly dispose of deadstock and document in accordance with established procedures.

  • Establish a dead animal pickup point away from pen areas and not in yard vehicle traffic patterns so that rendering trucks do not contaminate the operation.

  • Prohibit visitors from being near livestock unless absolutely necessary.


Create a Zoned Farm Diagram

Biosecurity sign do not enterA farm diagram is a useful exercise in helping to identify the high, medium and low risk areas of a farm. Once you are confident in defining these boundaries, then a plan for how to keep unnecessary vehicle and foot traffic away from high risk areas can be planned. It is also helpful in deciding where to put a sanitation station(s) for boot washing, clothes washing, and equipment and vehicle washing (when needed).

The diagrams below are sample layouts of a dairy farm. The first layout depicts the farm house, barn, parking area, milk house and other structures related to the farm. The second diagram demarcates three biosecurity zones:

  • Restricted access - high risk areas near livestock.
  • Transition zone - medium risk areas where the line of separation is located.
  • Controlled access - medium to low risk areas.

Employees, service providers and other permitted visitors would first enter a transition zone before any direct contact with livestock. Visitors would either exchange street clothing for disinfected boots and clean coveralls, or at minimum, asked to wear protective shoe coverings and wash hands.

The controlled access zone allows for vehicle entry, and will have anterooms located in this zone for sanitation stations. When visitors leave the restricted access zone and re-enter a transition zone, their protective boot covers would be removed and thrown away, or boots washed in detergent and disinfected. Employees may need to remove coveralls for laundering. It is also the limit of access for visitors who do not need to be in close proximity to livestock housing.

A line of separation or the clean/dirty line, first discussed in the sanitation section of this website, would be located in a transition or controlled area of access before entering the livestock area.

Biosecurity signage, discussed on the visitor signage page on this website, is placed in visible areas on the farm perimeter, and when visitors enter the restricted and controlled access zones, and transition zones to instruct employees and visitors to wash hands and clean boots.

  • Dairy farm diagram of restricted zones for biosecurityDiagram 1: Sample layout of a dairy farm.

  • Biosecurity zones marked for a dairy farm

    Diagram 2: Dairy farm layout with biosecurity zones.

A poultry farm sample diagram depicts where the restricted and controlled access areas are located, and the transition area (anteroom) where street clothing is exchanged for clean and sanitized clothing and boots, before entering the bird housing. The line of separation would be located in the transition area.

Sample biosecurity zone layout for a poultry operation.

Content Source for Biosecurity Zone Sample Layouts
Horowitz, Richard P., Ph.D. (2015). Biosecurity, Infection Control, and Continuity of Dairy Operations in FMD Response: A New England Perspective. Retrieved from http://nesaasa.weebly.com/uploads/1/2/7/3/12737832/biosecurity_infection_control_and_continuity.pdf

Farm and Barn Access Videos

The videos below were created by the North Dakota State University Livestock Extension, and do a great job of explaining how controlled and restricted access zones are used on a farm.

Animal Biosecurity: Farm and Barn Access
Farm and Barn Access for Visitors

Line of Separation

The line of separation, or the clean/dirty line, is part of planning to control visitor and employee traffic near livestock areas.