Gaps in on-farm biosecurity programs are often caused by focusing too much attention on the threat of disease posed by visitors, wildlife, birds and rodents, and not enough attention on staff and transport vehicles.
Pigs remain an obvious source of introduction of disease onto hog farms today. And area spread is still causing major headaches for producers trying to clean up diseases like porcine reproductive and respiratory syndrome (PRRS).
However, the industry's focus on some other elements of biosecurity is misguided, professes Carlos Pijoan, DVM, director of the Swine Disease Eradication Center at the University of Minnesota, who spoke at a biosecurity seminar during the mid-September Leman Swine Conference in St. Paul, MN.
People are an unlikely source of disease spread on hog farms that follow shower-in, shower-out principles. Work at the University of Minnesota and Purdue University has clearly shown that a shower and a change of clothes are adequate to prevent spread of diseases like PRRS, Mycoplasmal pneumonia and Transmissible gastroenteritis (TGE), he says. In many cases, the Danish system of a change of clothes and hand washing appears to stop transmission.
“There is no documented need for any ‘downtime’ between farms,” Pijoan asserts. “This is an onerous practice that is costly and places undue emphasis on procedures that do not solve the problem.
“It also puts the producer in a false state of comfort, by believing that a simple and obvious procedure will be enough to control the problems.”
Walter Heuser, DVM, Provis Swine Health Services, Steinbach, Manitoba, says downtime rules have created added costs for service personnel and employees, and restricted prompt access to units by veterinarians for diagnostic workups.
In western Canada, pig breeding company units still require three nights downtime prior to entry, but there is a gradual movement to one night downtime between commercial systems, he says.
Unlike visitors to the farm, staff workers pose a major threat to farm biosecurity, says Jean-Pierre Vaillancourt, DVM, Poultry Health Management Team, North Carolina State University. In a survey of biosecurity measures on 52 turkey farms, he found that only 21% observed biosecurity measures. In another survey of biosecurity measures on 23 poultry farms, he found disagreement on what should be or is happening on the farm.
Biosecurity compliance often falls on the shoulders of farm workers who do not have a good understanding of the importance of certain procedures and who generally do not profit from their compliance, says Pijoan.
Transport vehicles are becoming recognized as a major threat to successful biosecurity, according to Pijoan. Trucks should be properly cleaned and inspected before they are allowed back on the premises.
But even this may not be enough. “There have been several recent outbreaks of TGE that appear to be related to infected commercial truck washes, suggesting that even properly washed trucks may be a problem if the truck wash itself becomes the infection source,” he remarks. Pijoan suggests:
Use only farm-owned vehicles for all trucking done inside the premises;
Wash these vehicles on the premises and avoid commercial truck washes. An exception might be a truck that travels to a highly contaminated site such as a slaughter plant. Then, Pijoan advises prewashing the truck in a commercial facility with a final wash on the premises to avoid bringing an infected, dirty truck onto the farm; and
Allow all vehicles to completely dry before entering premises. “Dryness may be the single most important thing to audit for when inspecting trucks.”
Disease Control Strategies
To enhance the effectiveness of biosecurity, pork producers should think about changing production schemes and disease control strategies. Maintaining a clean herd in the midst of a hog-dense, infected region is difficult due to the uncertainty of area spread, says Pijoan.
A better approach would be to return to a “river of health” strategy where sites are kept separated and flowed all-in, all-out, much like the original concept of segregated early weaning, he says. This eliminates health challenges caused by filling units through multi-sourcing and commingling pigs of different ages.
Better yet, eradicate certain diseases from entire regions, he concludes.