When it comes to biosecurity in the swine industry, have we made progress? Montserrat Torremorell, interim department head and professor in the University of Minnesota College of Veterinary Medicine, said she doubts pork producers would have believed her 20 years ago that air filtration, disinfection of supplies, showers, bench entry system, cleaning/disinfection and drying of trailers, downtime, dedicated personnel and dedicated transport would be common practices to help keep disease off the sow farm.
“I think you can argue by all the biosecurity control measures we have implemented, that we have progress,” said Derald Holtkamp, professor at Iowa State University’s College of Veterinary Medicine during the Carlos Pijoan SDEC Symposium on Biosecurity and Biocontainment in Finishing Pigs at the Allen D. Leman Swine Conference. “But the annual incidence of porcine reproductive and respiratory syndrome (PRRS) hasn’t really gone down.”
So, what’s going on? Do biosecurity measures work? Holtkamp said it’s not all about the control measures.
“Over the last 35 years, we’ve added a lot of biosecurity hazards in how we do things. We are adding hazards faster than we are adding control measures,” Holtkamp said.
Consolidation. Emerging pathogens. Disease elimination methods. Total confinement. Geographic segregation of production. Contracting. Specialization. Economies of scale. Export markets/globalization. These are some of the changes the industry has made that are elevating the importance of biosecurity and at the same time, made it more difficult to manage, he explained.
In grow-finish, in particular, PRRS incidence is getting worse, Holtkamp said. One of the biosecurity hazards he’s been concentrating on lately is livestock transport.
Biosecurity Focus: Transportation
For virus infection to happen, three failures must happen. They include the failure to prevent viral contamination or infection, the failure to mitigate viral contamination or infection and the failure to prevent transmission of virus from the pathogen-carryig agent to pigs, Holtkamp explained.
In a study to assess viral contamination during market hog load-out, Holtkamp and his team evaluated if implementing a staged loading procedure for market pigs was effective at preventing transfer of swine pathogen contaminated particles from livestock trailers to the barn using fluorescent powder (Glo Germ) as a marking agent to be able to see traffic patterns. The study compared a conventional method of loading and a staged loading procedure.
The results revealed that four out of the five measuring points in the center alleyway of the barn had a level of contamination that measured significantly lower (p<0.05) for the staged loading protocol compared to the conventional loading protocol.
In standard loading protocols, there is typically one line of separation between the livestock trailer and the end of the load-out chute. The protocol is that load-out crew members cannot cross over this line into the livestock trailer and the driver cannot cross over onto the chute.
However, in a staged loading protocol, a second line of separation is implemented. One member from the load-out crew is stationed between the two lines of separation in which he or she cannot cross onto the livestock trailer or cross the second line of separation into the center alleyway of the barn. The remaining load-out crew members within the barn cannot cross the second line of separation into the load-out alleyway or chute.
Glo Germ was mixed with obstetric gel and dry wood chips and spread evenly on the floor of the livestock trailer, just inside the opening to the chute. Once load-out was observed and completed, researchers evaluated the Glo germ contamination using a grid of eight different measuring points within the chute after the first line of separation, two within load-out alleyway before the second line of separation, and five within the center alleyway.
The staged loading procedure did not completely eliminate contamination however, four out of the five points in the barn’s center alleyway had a level of contamination significantly lower in the staged loading protocol as compared to the conventional loading protocol. The difference at the fifth measuring point in the center alleyway of the barn was nearly significant (p=0.0573). The level of contamination measured at all other measuring points in the chute and load-out alleyway were not statistically significant between the two study groups.
Don’t Let Obstacles Prevent Progress
A staged loading procedure is effective at reducing the transfer of contamination from livestock trailers to barn. Holtkamp noted some challenges with staged loading. Not all barns are set up for staged loading.
“Training will be an issue,” he cautioned. “Workers are trained to help each other to keep pigs moving. They aren’t trained to be still and wait for pigs to move to them.”
Still, there are opportunities to improve, he said, whether that’s through a more effective use of gates or other barriers and even remodeling of some barns.
With African swine fever now in the Dominican Republic, Torremorell said the industry may not have a lot of time when it comes to getting biosecurity right.
“Perfection should not get in the way of good,” Torremorell advised.
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