Functional biosecurity systems continue to evolve rapidly in large swine production systems.
One of the big drivers in this evolution has been pre‑harvest food safety concerns, says R. B. “Butch” Baker, DVM, MS.
“Pre-harvest food safety concerns have played a significant role in total biosecurity interest,” says Baker, a swine veterinarian formerly with Premium Standard Farms and now with North Carolina State University College of Veterinary Medicine. “These concerns may eventually drive investment in more sophisticated biosecurity interventions.”
However, food safety consideration shouldn’t be the sole incentive for more progress in developing good biosecurity protocols for large production systems, Baker says. “The cost of health instability and potential value creation of high-health systems should be enough of an incentive for industry progress.”
At the same time, says Baker, one potential serious roadblock is the cost to implement an effective biosecurity program in a large production system. “This will have to be overcome if sustainable commercial health pyramids are to be developed. The recent return to industry profitability creates opportunity – unless it also causes amnesia with regard to the real costs of bad health.”
Baker says that even though pork production systems have evolved to include large populations that help create subsequent benefits from specialization and economies of scale, there still has been a concurrent general loss of realizable health in many of these production systems.
Gilt farms need to become the top of the health pyramid in today’s large commercial pork production systems.
Even though porcine reproductive and respiratory syndrome virus (PRRSV) has often been considered largely responsible for this, Baker says that “the dynamic ecological relationship between large populations of susceptible animals and numerous potential pathogens make the situation more complicated than this single virus‑host relationship. “The need for effective disease control strategies has never been greater,” he emphasizes.
“Functional biosecurity along with health pyramid development are the essential components needed to restore healthy and stable production systems,” says Baker. “As North American pig production continues to evolve into a global meat supplier, maintaining a competitive advantage will require strategies that eliminate and prevent disease and fulfill the marketing advantage offered by antimicrobial‑free production.”
In the past, industry leaders developed many of the biosecurity rules that have been traditionally used by the pork industry. “Although their ideas were steeped in common sense, these leaders had little scientific data to support or repudiate their principles.
“Over the years this situation has changed dramatically. PRRS, with its $500 million to $1 billion annual price tag, has created a need for biosecurity protocols to be driven by science, which has caused more biosecurity research in recent years,” Baker says.
More research is needed, however, he adds. “But research alone will not suffice,” he emphasizes. “Our industry must find effective ways to implement the biosecurity principles and standards that have already been developed in university research programs.”
Swine veterinarian Butch Baker says that pig transportation vehicles and trailers are responsible for nearly all biosecurity breaches in large production systems if health status of the genetic sources remains constant.
Baker says to develop functional biosecurity principles for large production systems, company-wide acceptance is needed. “No biosecurity plan will be successful unless there is company‑wide acceptance and a long term commitment to the process. It is easy to ‘talk the talk,’ but ‘walking the walk’ is the more difficult, but essential task. The starting point for all functional biosecurity plans is to train personnel in the basic principles needed to develop a sustainable system.”
The following primary issues need to be addressed when developing functional biosecurity measures for large production systems, according to Baker:
An understanding of the hierarchy of controllable risks is needed before establishing biosecurity priorities. “Not all risks are equivalent, and not all can be, nor should be, given equal attention. This fact is often ignored, and biosecurity measures are too often based on dubious observational conclusions or fears of the unknown.”
Managers need to rely on scientifically and historically valid information when developing swine disease control strategies. “Ignoring this principle will not only compromise biosecurity, but it will also needlessly elevate the cost of the biosecurity program.”
Managers must develop a sound understanding of the present level of biosecurity and the level of acceptance these current measures have among all persons involved in the production system. “By knowing this, managers can thoughtfully design ways to persuade and educate others to implement necessary improvements in the system. All individuals involved in the production system must be convinced they play a vital role in maintaining system heath. Only then will they be receptive to learning and implementing biosecurity protocols.”
Managers must consider the costs to implement new protocols, the odds of realizing sustained success with the protocols and the long‑term value that the measures may create.
According to Baker, the following “nonnegotiable” areas in the hierarchy of potential risk must be addressed when developing biosecurity programs in large production systems:
Site location. “Good location in low pig density areas is still the best deterrent against lateral introduction of disease agents. Many farms with minimal or sloppy biosecurity efforts have remained high‑health even in single‑site production situations. In this ideal situation, health status is totally determined by the health of genetic introductions. Unfortunately we are generally unable to alter today’s U.S. swine industry infrastructure. However, one thing that can be done is to move to dedicated, remote‑site multiplication, thus safeguarding the health status of replacement stock. Modern biosecurity requires introduction of healthy replacement stock.”
Farm staff and support personnel who breach biosecurity protocols in large production systems potentially transmit some swine disease pathogens.
Genetic supply health status. “Understanding the ongoing health status of the genetic supply is essential,” says Baker. “Introductions must be through true health pyramids, preferably through a dedicated, single‑site sow source. All health improvements and stability depend on the health and robustness of genetic introductions. With PRRS it is just as essential that the gilt be virus free.” The boar stud needs to be virus free as well. “The use of a functional quarantine period and isolation monitoring program is essential.” The single exception to breeding stock introduction biosecurity is in parity‑segregated systems, says Baker. “Due to weekly movement of second parity sows into multiple sow farms, the biosecurity success of the entire system is highly dependent on the health status of the gilt farms. Monitoring and quarantine are impractical beyond the initial genetic introduction phase. This situation will remain a challenge until real-time PCR reaches the farm. The entire gilt structure must be protected from lateral disease introductions sparing no biosecurity cost or consideration. The gilt farms should become the top of the commercial health pyramid.”
Pig transportation. Baker believes that pig transportation vehicles and trailers are responsible for nearly all biosecurity breaches if the health status of the genetic source remains constant. With PRRS, once the semen and gilt supply are PRRSV-free, at least 90 percent of the remaining controllable risk is associated with the internal movement of pigs. Significant areas that must be addressed are the truck wash and transportation scheduling. Trailers remain contaminated with viral and bacterial agents regardless of the efforts made to clean, wash, disinfect and inspect. Overnight dry‑down and heated systems above 160°F hold promise in solving this problem.
Farm staff and support personnel. “There is little doubt that Salmonella, E. coli, PRRS, TGE and swine influenza are potentially moved about by individuals who breach biosecurity protocols. Showers typically protect against most disease introductions, if only to force a change of clothing. Influenza is deserving of special consideration because humans play an active carrier role. Downtime rules are useless when attempting to prevent its introduction. Influenza vaccination of all direct farm and support staff may be a necessary biosecurity effort to prevent influenza introduction, but high compliance will be a challenge, says Baker.
North Carolina State University swine veterinarian Butch Baker believes that functional biosecurity and health pyramid development are essential components needed to restore healthy and stable pork production systems.
There are other controllable risk factors that are a small percentage of the total risk picture, but they need to be addressed as well, Baker says. These include feed trucks, feed ingredients, supplies, maintenance systems, waste management personnel and equipment, water, and contract vendors.
Water and the contract vendor are also critical. “A vendor training and inspection program, along with strict shower protocols will solve most of this security concern.”
As for water, Baker says that production systems that don’t have rural or municipal water supplies, may have major biosecurity risks. “Chlorine injection and other on‑farm purification systems are typically nonfunctional. “Any surface water usage will allow significant introduction of pathogens. Avian tuberculosis, EMC virus, PRRS, influenza, leptospira, parvovirus and many other bacterial, viral and para-sitic agents can and frequently do enter through the water supply.”
Editor’s note: Information in this article is based on a presentation at last fall’s University of Minnesota Allen D. Leman Swine Conference in St. Paul, Minn.