Selling the importance of biosecurity to producers

Biosecurity is no joke. Most practitioners are aware of its significance considering the media focus on bovine viral diarrhea (BVD), bovine spongiform encephalopathy and agroterrorism. Yet veterinarians who are known to make a host of producer safety recommendations often omit some security suggestions because they appear excessive.

However, it's the more extreme measures that stress the seriousness and importance of strict farm biosecurity and might make producers wake up to the fact that this is not a trivial matter. When it comes to securing the nation's food supply, a recent meeting on disease risk management by the Center for Food Security and Public Health at Iowa State University provides a wealth of information. The agency offers fact sheets on biosecurity, foreign animal diseases, zoonoses, disinfectants and much more. It also creates tools for farm assessments in the name of disease prevention.

Biological risk management

Although much focus is placed on foreign animal diseases such as foot-and-mouth disease (FMD), practitioners know many domestic diseases routinely pose problems for producers, and each disease has distinctive characteristics when it comes to management. The task of preventing many diseases simultaneously can be overwhelming for producers. However, if approached from the route of transmission perspective, it becomes simpler. If all possible routes of transmission are managed, prevention of all diseases, whether foreign or domestic, can be managed.

Routes of disease transmission

Some of the routes of transmission are common and easy to remember. Others are easily overlooked, so it helps to review how diseases spread.

• Aerosol: Droplets are passed through the air from one animal to another.

• Direct contact: The disease agent touches open wounds, mucous membranes or skin through blood, saliva, nose-to-nose contact, rubbing or biting. Reproduction is a subtype of direct contact that includes a disease's spread via mating or to the fetus during pregnancy.

• Fomite: An inanimate object carries a disease agent from one susceptible animal to another. Traffic is a subtype of fomite transmission in which a vehicle, trailer or human spreads organic material to another location.

• Oral: This involves consuming disease-causing agents in contaminated feed, water or licking/chewing on contaminated environmental objects.

• Vector-borne: An insect acquires a disease agent from one animal and transmits it to another.

The following recommendations are aimed at preventing the entry of disease as well as monitoring and prevention in case of a biosecurity breech.

Animal identification, herd records

Most producers have some experience with animal identification and record keeping. Animals should be individually identified. Currently available individual identification tags include orange and silver metal clips used for years for regulatory work as well as electronic identifications. A dangle tag number 12 or ear tattoo R106, for example, are not individual. Individual identification helps prevent any mix-up of animals, and the best option is a dangle tag that is easily seen and is cross-referenced with the individual tag. That way if one falls out, the animal still has some identification.

This system allows the producer to keep better production and health records. It's also needed to record animal movements on and off the farm. Herd introduction dates, where the animal was purchased and its origin, movements on and off the farm and in between units should be recorded.

Farm disease monitoring, control

Practitioners should review the nutrition and vaccination programs of herds to boost non-specific and specific disease immunity. Encourage producers and their employees to clean equipment and change clothing between groups of animals and when returning from another farm. Observation of animals for signs of disease, prompt treatment and necropsy of animals that die or are euthanized are important for early recognition and prevention of possible disease spread. Producers should limit new introductions and animals traveling off the farm for shows and sales then returning as much as possible. A quarantine area should be set up for these animals as well as sick animals.

One of the most overlooked breeches in biosecurity occurs when show animals are returned to the farm and not quarantined. Since this animal is not a new purchase and appears healthy, producers might overlook this risk. Taking pregnant animals to shows has the added risk of introducing BVD that a quarantine period will not eliminate. Testing for diseases or purchasing from herds certified for certain diseases is prudent when obtainable. Finally, nothing takes the place of good sanitation on the farm, especially when it comes to preventing calf diseases.

Controlling people and vehicle movements

This area is where many of us tend to get lax in our recommendations. However, there are many examples of disease entering a farm on a person or vehicle, so recommendations to prevent this are important. Securing the farm perimeter is a prudent move for several reasons, not just for preventing entry of disease. Fences should be maintained to keep the farm's animals in and other animals out. Deer can pose a biosecurity risk, but keeping them out usually is cost prohibitive. Although expensive, double fencing between neighboring farms should be considered to prevent spread of disease through aerosol or direct contact. This might not control vector-borne transmission, which is difficult and usually vector-specific. Gates should be locked to prevent people and vehicles from gaining access without permission. Delivery trucks should have limited access to the farm and travel and park on paved or rocked surfaces. These areas are more likely to stay dry and have direct exposure to sunlight, which help decrease pathogen loads.

With much of the population unfamiliar with agricultural practices, we should encourage visitors to livestock operations. However, some precautions should be taken. All visitors should sign a registry and be escorted on visits. Non-agriculture visitor groups, especially youth groups, are unlikely to bring a disease onto the farm, but they are at risk of leaving with a potentially zoonotic disease. They should be advised to "look but not touch" and have a place to wash their hands following a farm tour. Visitors from other farms, particularly international visitors, are a bigger biosecurity risk. Provide disposable boots, and don't allow direct contact with animals. This works fine for visitors but might insult friends and family who come to help. Producers should still ask that they come with clean boots and clothes, and promise to do the same when they return the favor of helping out. Providing water, disinfectant and a brush will allow helpers to wash before they return home to their own farms.

Management tips

Producers tend to focus on specific diseases, but we know that many of the diseases we see in practice are the result of underlying management factors. Biosecurity lapses are one of those factors. We must stress to producers that it is futile to try to eliminate a disease if they are not going to prevent its reintroduction. Different farms have different risks, and a biosecurity program should be tailored to the individual operation. Risks of disease entry and spread should be evaluated and prioritized so the most significant risks are addressed first. The practices discussed are just a start, and some farms, particularly those more intensely managed like dairies and feedlots, might need more stringent work.

Dr. Navarre works as an extension veterinarian with Louisiana State University's Department of Veterinary Science.

Biosecurity on the Web

Visit the Center for Food Security and Public Health at www.cfsph.iastate.edu for fact sheets on biosecurity, foreign animal diseases, zoonoses, disinfectants and more. Related farm assessment tools also can be found on the site.