Ohio State University Extension Fact Sheet
Veterinary Preventive Medicine
1900 Coffey Road, Columbus, OH 43210
Biosecurity Fundamentals for Extension Personnel
Gary L. Bowman, D.V.M.
Extension Veterinarian, Swine
William P. Shulaw, D.V.M.
Extension Veterinarian, Cattle and Sheep
The Ohio State University
The prevention of livestock disease outbreaks is of concern to the entire agricultural community and especially to
Extension personnel. The mass culling of United Kingdom livestock
in early 2001 because of Foot and Mouth Disease (FMD)
has heightened interest by demonstrating the vulnerability of a
nation's animal resources. Extension personnel and other
agricultural professionals need to be knowledgeable in livestock
disease prevention procedures because they serve as an
information resource for their community's producers, and they must be
role models when duties may take them to livestock facilities.
Biosecurity Its Meaning and Implications for Livestock Production Units
Biosecurity, in the context of livestock production, refers to those
measures taken to keep disease agents out of populations, herds, or
groups of animals where they do not already exist. Biosecurity measures
can be implemented on national, state, and herd levels. While there is
increased awareness of FMD as a national biosecurity issue, the USDA
continues to be vigilant as it attempts to keep many foreign animal
diseases out of our livestock population. In addition to national
concerns, individual states take measures to prevent the
entry/reintroduction of livestock diseases they have been able to
prevent/eliminate from herds in their state. They do this by setting
requirements for arriving animals. Examples of diseases that are of
particular concern to states include brucellosis, tuberculosis, and
pseudorabies. Herd-level biosecurity usually rests with the herd owner
or management team; they try to exclude any disease which is not already
present in the herd and to limit the spread of existing diseases within
the herd. Examples might include mastitis caused by Streptococcus
agalactiae, bovine virus diarrhea, ovine progressive pneumonia, and
swine dysentery. To be valid, a biosecurity plan should at least address
1) how a group of "new" animals will be isolated away from
other groups, 2) how traffic (movement of people, animals, and
equipment) will be regulated, and 3) how cleaning and disinfection
procedures will be designed to reduce pathogen levels.
Every flock or herd manager who hopes to raise livestock profitably
must address issues of herd health maintenance. It is well documented
that diseased animals are not as profitable, thus it is in the
producer's best interest to adopt a biosecurity plan designed to prevent
and control disease.
Biosecurity measures can be categorized as either external
measures those measures taken to prevent the entry of new diseases
into a herd or production group or internal measures those
measures taken to prevent the spread of a disease already in the herd to
other uninfected groups or subpopulations within the herd. In general,
diseases within a herd spread from older animals to younger animals.
This fact sheet will address primarily external biosecurity
measures for livestock.
Comprehensive biosecurity programs have already been adopted by many
poultry and pork producers as they have recognized the need to safeguard
the health of their flocks and herds. With the relatively large number
of birds or pigs housed in a modern production unit, disease prevention,
rather than disease treatment, is easily the better alternative. Basic
issues to consider in a biosecurity program include isolating new
animals, controlling the movement on the farm, and sanitation.
Efforts should be prioritized to address those factors posing the
greatest risk for disease introduction. Regardless of the livestock
species, the most common way contagious diseases are introduced is by
adding animals to the herd, typically replacement breeding stock. Merely
excluding obviously sick animals is not sufficient to prevent disease
introduction; new stock may be incubating diseases to which they were
recently exposed, or they may be carriers and shedders of disease
organisms. In these cases, it is likely that they will have no apparent
signs of disease upon arrival at their new home.
To reduce the risk of introducing diseases with additions to the
herd, the following general guidelines should be adopted:
- The health status of the source herd should be reviewed. The
number of source herds should be minimized; single-source animals
are preferred over commingled animals. If there are diseases present
in the herd-of-origin that are not in the recipient group, the
acceptability of animals from this source should be questioned.
Procuring animals from a source that has a lot of exposure because
it participates in many exhibitions or it frequently purchases
animals increases the risk compared to using a closed herd as a
source. Animals obtained through sales or auctions, where animals
from many sources are commingled, generally have a greater risk of
disease than those purchased directly from the herd of origin.
- All new or returning animals should be isolated from the herd
for at least two weeks and preferably four weeks. (Many swine herds
now require a strict 30-day isolation period followed by a 30-day
acclimation period before new animals are introduced to the herd.)
- The isolation facility should be at least several
hundred yards from the rest of the herd and positioned so
that surface drainage and prevailing winds do not carry
contamination to the herd. As a rule of thumb, the isolation
facility should be far enough away so that it is not readily
and easily accessible to personnel as they perform their
other regular farm duties.
- The isolation facility should be managed all-in/all-out.
No animal should be moved from the isolation facility to the
recipient herd until the most recent addition has completed
the testing protocol and isolation period.
- Animals should be carefully observed at least daily
during the isolation period. Those showing signs of illness
should be penned separately and promptly examined by a
- Tests for diseases of specific interest can be
accomplished before the isolation period ends. Acceptable
test results should be received before animals are released
- Preventive treatments such as deworming and vaccination
can be started in preparation for moving to the herd.
- Outerwear (boots, coveralls, coats, gloves, hats) worn
while tending these animals should be restricted to the
- Duties should be sequenced so the person caring for the
isolation animals does not come into contact with other
animals later that day. If possible, the person taking care
of the isolation animals should have no other animal-contact
- Equipment such as feed containers, hurdles, snares,
halters, blankets, shovels, forks, scrapers, etc., used in
the isolation facility should not be used in other units.
Assessing the Disease Risk Posed by Visitors
Although diseases are most commonly introduced into a
herd by the addition of animals, there is a risk of disease
introduction by people traveling between groups of animals. This risk
may vary considerably and is influenced by the specific disease
agent, the extent of the animal contact, the time elapsed since the
last animal contact, and the preventive measures used.
Low-risk visitors include those from urban areas or those
who have had no livestock contact. Although these visitors
present very little risk of introducing disease to the farm, some
precautions might include:
- Asking visitors to wear freshly laundered outerwear
and clean footwear. You may wish to provide them with
disposable plastic boots (or clean rubber boots which remain at
the farm) and coveralls as an added precaution. This not
only reduces the disease risk for your animals but also
helps prevent guests from contaminating their clothing with
germs from your farm.
- Not relying heavily on disinfectant-filled boot baths. Research
has shown the use of boot baths to be an unreliable method of
routine disinfection, unless boots are thoroughly scrubbed before
immersion and adequate contact time in the disinfectant is permitted
usually at least five-minutes contact time is required.
- Not allowing visitors to enter pens, walk through feed
alleys, or touch animals unless necessary.
- Not allowing visitors to bring food articles with them on
- Providing a plastic bag for collection of disposable boots
and asking guests to wash their hands (and boots, if
worn) before leaving.
Moderate risk visitors include those people who routinely
visit farms, but who have little or no actual contact with
animals. Salesmen, feed and fuel delivery drivers, and maintenance
workers are examples of this group. They should be expected
to observe the same precautions as stated earlier and in addition:
- They should wear clean coveralls and boots if there is any
contact with feed, animals, soil, or manure.
- Any sampling equipment should be properly cleaned and
disinfected between uses.
- Dirty boots should be cleaned and disinfected, and coveralls
should be removed and placed in a clean plastic bag or container
before re-entering the vehicle.
High-risk visitors are those people who come into
direct contact with livestock in their work and would include
inseminators, processing crews, veterinarians, livestock haulers,
and livestock-owning neighbors. These people typically have
direct contact with animals and their bodily discharges. In addition
to the precautions listed earlier, other recommendations
- Vehicles should be clean and free of visible manure on
the tires and wheel wells and should be kept away from
animal areas and driveways used by the farm's own vehicles. In
an emergency disease situation, such as the presence of FMD
in the United States, restrictions on access to the farm should
be in place and disinfection of vehicles should be
considered even if not mandated. In the event FMD occurs in Ohio,
these procedures will be mandated. Vehicle interiors should
be clean and easily cleanable. Livestock trucks and
trailers should be clean and dry, and preferably disinfected,
before arrival on the farm.
- Visitors should arrive with clean clothing, boots, and
equipment. Equipment and instruments that have direct
animal contact (dehorners, castration equipment, halters, etc.)
should be cleaned and disinfected (or sterilized) after use
and maintained in such a way that they do not become
- Disposable sleeves/gloves, other disposable clothing,
or clothing that can be disinfected should be worn
whenever there is the possibility of direct contact with bodily
discharges or animal tissues.
- Before leaving the farm, dirty equipment and footwear
must be cleaned and disinfected with an appropriate
chemical agent. Soiled coveralls should be removed before
re-entering the vehicle. Potentially contaminated hands and
forearms should be washed with soap and water.
- 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
own livestock. They could provide their own clean coveralls
and disinfected boots, or it may be easier to supply
employees with outerwear and boots that are left at the farm when
the employee returns home. As a condition of
employment, some employers now prohibit their workers from caring
for livestock outside the employer's herd.
Suggested Biosecurity Guidelines for Extension Personnel Visiting Farms
- When planning a visit to a livestock facility,
Extension personnel should contact the herd manager to discuss
the farm's requirements for biosecurity in terms of
clothing, animal contact, showering, etc. Even if not required by
the farm, Extension personnel should, at a minimum, set
the example by using measures that would seem prudent for
a well-managed farm.
- Expect farm managers to question potential visitors
about recent contact with animals in other herds or visits to
foreign countries. In the course of the interview, the manager
can decide whether the person represents a low, medium,
or high-risk visitor and then take appropriate measures.
- Avoid unnecessary animal contact when visiting
livestock facilities. For observing outside buildings and outside
fences, new disposable plastic boots or protective footwear
supplied by the farm should be used.
- Extension personnel should be dressed in clean
outerwear (not worn on any other farm since being cleaned) if it
is necessary for him/her to be in buildings, alleyways,
lots, pens, or pastures normally accessible to the herd.
- Disposable coveralls and disposable plastic boots are
recommended; however, clean laundered coveralls and clean
disinfected rubber boots may be acceptable. If disposable outerwear
is impractical, the farm being visited should supply the
reusable coveralls and boots to reduce the chance of
additional pathogens being introduced. Because of the difficulty
in satisfactorily disinfecting reusable boots, plastic
disposable boots (6-mil thickness recommended), are suggested
for most cases. However, disposable plastic boots are
more subject to leaks when worn for an extended time or
on abrasive surfaces, and they provide very poor traction
for walking in snow or on smooth wet floors. The
biosecurity risk must be weighed against the safety risk associated
with their use.
- If Extension personnel supplying the outerwear,
coveralls should be clean or new and should be protected from
cross-contamination with dirty items. Plastic storage
containers with sealing lids can be used for storing and transporting
the new and/or clean coveralls and disposable boots.
Clean rubber boots can be sealed in a plastic bag until needed.
To minimize the difficulty in cleaning rubber boots, the
boots should be free of creases, folds, and buckles; the
tread pattern on the bottom should not be aggressive so that
debris cannot be removed easily. Head covers and dust masks
can provide added protection. In cases where clean rubber
(reusable) boots are used, they should be dipped or soaked
in disinfectant solution as part of the donning of the
coveralls and boots just before entering animal facilities.
- When actual contact with animals is a possibility, no
more than one farm or herd should be visited on the same day,
if possible. (Note: For admission to many well-managed
confinement swine and poultry units, the visitor must not
have been on another farm in the past 2448 hours. Even
then, they must shower-in and wear only farm-supplied clothes.)
- When leaving the farm, protective outer-clothing worn on
a farm should be removed before entering the vehicle and
left on that farm if at all possible. Reusable coveralls should
be placed in a plastic bag and tied-off until they can be
laundered. Reusable boots should be scrubbed free of debris
with water, soaked in disinfectant solution, and then placed in
a plastic bag or other container for transport allowing
the disinfectant to dry on them.
Biosecurity Issues to Consider When Planning a Farm Tour Where Livestock Are Present
- Discuss with herd owners/managers their biosecurity
expectations. This may vary greatly from farm to farm. In
general, breeding herds have more concern about biosecurity
- Designate a person to serve as biosecurity advisor;
this person can help formulate policy and answer questions.
This likely will be the herd veterinarian.
- Publish the biosecurity standards for the event in the
tour announcements and promotional materials. If registration
or sign-in takes place at the farm on the day of the tour,
the biosecurity standards can be reinforced at that point.
Consider including information on:
- Dress standardsClean outerwear not worn on
another farm since cleaning.
- BootsDisposable plastic boots are preferred
and will be supplied. Reusable rubber boots will be examined
for cleanliness and suitability, and approved by the
biosecurity advisor or designee. Anyone wearing reusable
boots will disinfect them before entering the farm.
- Foreign travelersAdvising persons who have
returned from traveling outside North America in the past
seven days to notify the herd manager or biosecurity advisor
about participating in the tour. The biosecurity advisor can
evaluate the risk and render a decision about the person's
participation in the tour.
- Food productsFoods of animal origin should
not be brought onto the farm unless approved by the herd
- Establish an entry point from the parking area to the
animal facilities through which all visitors will pass. A sign
may indicate boots are needed beyond this point.
- Disposable boots should be the standard if the tour is
to include walking in livestock buildings and in pastures
or forages that will be harvested for animal consumption
within two weeks. Admittedly, reusable rubber boots are
more durable and give better traction in many conditions.
- If disposable plastic boots are deemed unsuitable for the
tour and reusable rubber boots are used, a boot washing
station should be set up. The station should have provisions
for scrubbing and rinsing all visible soil off the boots. The
boots are then immersed in a clean disinfectant solution for
five minutes before entering the premise.
- Minimize actual contact with animals, animal waste,
and discharges. Keep visitors back 10 feet or more where
- Provisions should be made for cleansing hands and
exposed skin if actual animal contact is anticipated. Consider
providing alcohol-based hand rinses and cleansing gels where
soap and water are not readily available. Hand washing is
especially important if children, the elderly, or
immunosuppressed individuals will be participating in the tour.
- If food and refreshments are to be available at the tour
site, they should be prepared, served, and consumed away
from the actual livestock facilities to minimize the possibility
of microbial agents of animal origin contaminating the
food. While hand washing before eating is always
recommended, hand washing facilities for patrons should be
considered essential if they will be actually touching the food they
are consuming finger-foods such as chips, cookies, ice
cream cones, sandwiches, etc. as compared to beverages in
a bottle/can/cup or food eaten with a spoon/fork. As an
alternative to washing hands with running water and
soap, consider making a cleansing gel or waterless
alcohol-based hand rinse and paper towels available near the food
concession. These hand rinses are widely available over-the-counter.
- Provide a receptacle for discarded plastic boots
convenient to the point where visitors will be departing from the
animal area. Ideally, the used boots (and disposable coveralls)
can be bagged in plastic trash bags and then placed in a dumpster for removal.
Guidelines for Visiting Multiple Livestock Projects
It is sometimes necessary to examine and tag project
animals at several different locations on the same day (such as a
4-H advisor observing club members' livestock projects).
When facing such a task, the following items should be considered
in the interest of good biosecurity.
- Schedule as few farms as possible having the same
species of animals on any given day. It would be better to visit
one hog project, one lamb project, and one steer project in a
day rather than three lamb projects.
- Give farms with full-time livestock production units
the opportunity to be visited first on a given day. The impact
of a biosecurity breach is much less for locations where
there is only a market project animal(s).
- Keep the number of people in the traveling party to
the minimum needed to accomplish the job. For biosecurity,
it would be better to have multiple small groups
visiting separate farms rather than one larger group that has to
visit all the farms.
- Use disposable plastic boots if the visit requires
entering animal facilities. If animal contact is possible,
coveralls should be worn. Alternative ways to handle coveralls,
in descending order of preference:
- New disposable coveralls for each farm.
- Coveralls to be worn by visitors are supplied by each farm.
- Visitor supplies clean reusable coveralls for each stop.
- Request that each farm supply as much equipment as
possible for use with their own animals (nose-leads,
snares, tattoo sets, tagging pliers, buckets). Clean and sanitize
all transported equipment before and after use at each location.
- Before and after handling animals at each location,
cleanse hands and exposed skin subject to animal contact.
Consider wearing disposable examination gloves whenever possible.
- Leave used disposable items (boots, coveralls, gloves) at
the farm where they are used. All the items can be sealed in
a small trash bag for convenient disposal by the owner. If
clean and contaminated items will be transported in the vehicle
of the visitor, separate containers for each should be used
to prevent cross-contamination.
The information in this fact sheet is intended to raise
issues related to biosecurity that merit consideration if animals are to
be moved between established groups, or if people move
between groups of animals. Each recommendation should be evaluated
on its own merit for the specific situation. An animal health
specialist should be consulted in formulating the good
management practices to prevent and control disease in livestock populations.
Click here to view the PDF of this Fact Sheet.
All educational programs conducted by Ohio State University
Extension are available to clientele on a nondiscriminatory basis without
regard to race, color, creed, religion, sexual orientation, national origin,
gender, age, disability or Vietnam-era veteran status.
Keith L. Smith, Associate Vice President for Ag. Adm. and
Director, OSU Extension.
TDD No. 800-589-8292 (Ohio only) or 614-292-6181
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