Coming and Going:
Biosecurity from the "Down and Dirty" Perspective
By Roger Weigle, DVM
Associate Vice President Animal Health, Genex
In the previous installment of this series, we talked about the use of disinfectants in preventing the spread of disease organisms around the farm. We tried to focus on the fact that one cannot disinfect any surface unless that surface is already clean. Let's now focus on the people you have moving around your farm, and how they can either help or hinder your facility's biosecurity.
The vast majority of farms in the United States and Canada employ hired labor in many forms, from daily employees to custom outfits that come intermittently to make/process feeds or haul manure. Almost all farms have feed and supplies delivered to the farm frequently and trucks are always arriving to remove the milk produced. Any one of those people or vehicles could be the one to put you out of business.
The world is changing. We live and do business in a global environment with people, animals, goods and services moving around the globe in ever increasing numbers. Let's talk for a bit about "foreign diseases," which are better known as Transboundary Animal Diseases (TAD). The best known example of this is Foot and Mouth Disease (FMD), a viral disease not present in North America, but present in many parts of the world. It can be transmitted on inanimate objects like shoes or clothing, and can live for weeks in soil or manure, salted or cured meats, or hides. It does not cause disease in humans, but can live and be spread from the nasal passages of people for a day or two.
We all remember the stories, both recent and in the past few years, about the FMD outbreaks in Great Britain, and the photos of dead animals being burned to prevent the spread of the disease. Think it can't happen here? There are as many as 35 million foreign visitors to the United States every year, and any one of them could be the source of either an accidental or purposeful introduction of TAD. Computer disease models have shown that once here, some TAD could be in as many as 40 states within a week of introduction.
With that in mind, let's go back and talk about the folks that come on and off your farm on a daily basis. How many of the people working for you keep animals at home? Do you know? The animals we should be interested in are "susceptible species" that can share diseases. Those generally include cattle, sheep, goats and pigs. The reason for our concern is that if an employee has animals of his/her If an employee has animals of his/her own at home, the health status of those animals can directly effect the health status of your herd, as diseases can be carried on the clothing of the employee to your animals.
It is a very good idea to provide clothing and footwear for use on your farm, which stays on your farm. Employees should be asked to come to work in clean clothing that has not had animal contact at home, and to then change into work clothing that stays on your farm. If you have different levels of biosecurity on your farm (and you should), there should be clothing and boots available in each area, that stays in the area of use. For example, a person who has been working with cows should not go work with newborn calves, unless they wash up and don a different set of clean coveralls and boots.
People that must work in multiple areas start in the area of highest biosecurity (the "cleanest" or most susceptible animals), and work down the line to the dirtiest or least susceptible ones. Basically, work in the sick pen last.
At Genex, we have a minimum of three different biosecurity zones, and each zone has its own equipment and personnel.
Biosecurity levels or zones are clearly defined at Genex facilities, as seen on the signs above. The signs are placed on facility entrances as well as equipment used within that biosecurity zone. The signs also indicate that employees must change their boots and coveralls when moving between zones.
How about the employee's vehicles? They should be parked in an area out of the general traffic pattern for the farm, and not share routes used by feed wagons and other equipment used around the animal population. Feed trucks and vendor's vehicles should have the same requirements, and access to the farm only on roads not commonly used by farm vehicles. Off-farm vehicles should never have access to the inside of an animal building unless they have been disinfected and inspected prior to admission. And that goes for the electrician, plumber or artificial insemination technician. (See farm layout example below.) Do you think this is overkill? It just depends on how badly you want to stay in business.
This farm layout example follows the rule of not sharing driveways between farm vehicles and non-farm vehicles. Feed trucks can make drop offs by traveling in the first driveway. Employees, visitors, electricians, A.I. technicians, Etc. use the third driveway.
What about the employee that goes home to Colombia or Brazil for a visit? If they have animal contact in their home country, I recommend they not have contact with animals in this country for at least ten days after they return (with at least five of those in this country). Currently, any country north of Panama is considered free from FMD, so those stringent rules need not be applied to employees from north of Panama.
It all comes down to common sense. Folks should be trained on how to move around the facility, without carrying disease-causing organisms along with them.
Author Bio: Dr. Roger Weigle graduated from Kansas State College of Veterinary Medicine and gained industry experience at the Kansas Artificial Breeding Service Unit. After 25 years of private veterinary practice, Dr. Weigle now leads the cooperative's animal health programs.
