State University Extension Factsheet

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:

  1. 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.
  2. 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.)
    1. 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.
    2. 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.
    3. 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 veterinarian.
    4. Tests for diseases of specific interest can be accomplished before the isolation period ends. Acceptable test results should be received before animals are released from isolation.
    5. Preventive treatments such as deworming and vaccination can be started in preparation for moving to the herd.
    6. Outerwear (boots, coveralls, coats, gloves, hats) worn while tending these animals should be restricted to the isolation facility.
    7. 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 duties.
    8. 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:

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:

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 might include:

Suggested Biosecurity Guidelines for Extension Personnel Visiting Farms

Biosecurity Issues to Consider When Planning a Farm Tour Where Livestock Are Present

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.

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.

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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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