Pathways and Vulnerabilities

Not only do different types of visitors pose different levels of risk, but so do different areas of the farm and different groups of animals. The areas housing animals that are more susceptible to the introduction or potential transmission of infectious diseases are high-risk areas. The animals that are most susceptible to disease are young animals, animals that have just been recently moved or weaned, animals before and after giving birth, and animals that are already sick. These animals are also most likely to shed microbial organisms, such as bacteria, viruses or protozoans that can infect other livestock. Some of these pathogens can cause illness in humans as well.

In general, an increased risk of disease is associated with:

  • Farm Density

    Other farms and facilities within a few miles.

  • Animal Movement

    Especially if animals leave and then return to the farm premises.

  • Traffic On and Off the Premises

    Vehicles (feed deliveries, milk trucks, garbage haulers, rendering services), and their drivers.

  • Equipment Sharing

    Between farms or between animal groups within a farm.

  • Access by Wildlife

    Birds, insects, rodents, feral animals, wandering domestic animals (dogs and cats)..

  • Animal Housing

    Construction that is difficult to clean and disinfect.

  • Mortalities

    Carcasses disposed near animal housing.

Between-herd Risk Factors

The greatest risks to the health of livestock on your farm are from other animals or their manure. In order of risk, from highest to lowest, are the following situations:

  • Adding new livestock to the farm without a quarantine period.
  • Failing to quarantine new additions for at least two weeks, preferably four weeks.
  • Failing to require testing for specific diseases prior to addition.
  • Failing to require vaccination for specific diseases prior to addition.
  • Allowing livestock to return from fairs, shows, or exhibitions without quarantine.
  • Allowing other animals (domestic or wild) to contact your livestock, feedstuffs, or water sources.
  • Failing to prevent disease transfer via human contact, vehicular traffic, or equipment (including needles and rectal sleeves) used on more than one animal.


Three mule deer standing together in a snowy field.Where their paths cross, livestock can be exposed to disease-causing agents carried by wildlife. This may happen at a water source that livestock share with Canada geese or a feed manger that also happens to be home to a family of mice. These are just two examples of where contact and transfer of disease can take place. You need to be aware of the risks posed by wildlife.

The three main areas targeted as wildlife biosecurity concerns are:

  • Feed (particularly feed storage)
  • Water sources
  • The living space for the herd.


Whether coming to see a "real farm" in action or to conduct business on your farm, visitors come with the potential to introduce new diseases or spread existing infections to more animals. Different types of visitors pose different levels of risk. For some visitors, the diseases present on a farm may pose a risk to their own health.

A group of women and men are standing around a man who is talking about caring for sheep, standing next to a pen with four sheep in it.Not only do different types of visitors pose different levels of risk, but also different areas of the farm or types of animals are more susceptible to the introduction of or potential transmission of infectious diseases. Unlike many large swine and poultry farms, most dairy farms do not go as far as prohibiting visitors or making them shower in and shower out, but all farms do need to evaluate the risks posed by various types of visitors and develop strategies to minimize threats to the health of their livestock.

Traffic patterns for visitors in vehicles and on foot must be considered when developing a biosecurity plan. General guidelines are provided in this section. Understanding which areas of the farm are at highest risk for disease introduction or transfer, as well as being able to identify the level of risk posed by various people coming onto the farm will help you develop an effective plan. Examples of farm signage and instructions for preventing foreign animal diseases are also included in this section.

The most critical component of all is vigilance in enforcing the plan. Protecting the health of your animals should be a priority for you and your employees. The ultimate responsibility for communicating and carrying out the biosecurity plan on a farm rests on the owner's shoulders.

General Guidelines for All Visitors

A young girl is holding her hand out to touch the nose of a cow.Guiding the movement of visitors, personnel, and vehicles will minimize cross-contamination from one part of a farm to another.

  • All high-risk visitors and farm employees should follow the clean to dirty, young to old, healthy to sick order of work.
  • Work routines, such as feeding and milking, should start with healthy and younger animals then go to sick or older animals.
  • Work should also move from clean to dirty areas. For example, start in feed storage or feeding areas and end in the free stall alley. Make every effort to prevent the contamination of feedstuffs with manure.
  • Everyone who will come in contact with livestock, manure, or other bodily fluids should arrive with clean boots and coveralls, and be sure to clean their boots and wash their hands before leaving the farm.
  • Parking areas should be located away from livestock, feed delivery areas, and manure handling routes.
  • Only the farm's vehicles should be allowed in livestock handling and housing areas or around feed storage areas.
  • Use the farm's vehicles to transport visitors, employees, and agri-service personnel.
  • Animal and deadstock pickup areas should be located near an access point that is set apart from barns, pastures, or other livestock areas.

If your farm regularly hosts visitors, you should do the following:

  • Have a single, clearly marked entrance for all visitors to control the flow of traffic.
  • Refuse entry to visitors who have returned less than a week ago from areas of the world where foot and mouth disease or African swine fever exists. Consider refusing entry to all visitors who have traveled outside of North America in the past five to seven days.
  • Keep a visitor log to record who was on the farm and when.
  • Maintain accessible, functioning hand and boot wash stations.
  • Supply disposable plastic boots for visitors who need them, and provide a means for their disposal on the farm.
  • Know the risk posed by your visitors (low, medium, or high) and prepare accordingly. Clearly mark and restrict access to all high-risk areas.

Visitor Risk Assessment

Characteristics about low, medium and high risk visitors to a farm.