Prepare for African swine fever outbreak with Secure Pork Supply plan

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A growing threat of African swine fever (ASF) has convinced US pork producers to prepare for the worst with a Secure Pork Supply plan, reports Paul Yeske, DVM, Swine Vet Center, St. Peter, Minnesota.

“The Secure Pork Supply (SPS) plan was put together as a mission to improve biosecurity and to help make sure [if] a foreign animal disease enters the country that we have a plan for farms to survive,” he said.

The voluntary SPS plans help producers implement a more complete biosecurity plan to assure others that their herd is negative. This will allow the farm to continue business and move pigs, if needed, in the face of a foreign animal disease outbreak such as ASF.

SPS plans underway

In most cases, veterinarians are helping producers work through the plans.

“That’s been one of our roles — work with clients to set up the biosecurity plans, to help designate the sites, draw the maps of the sites and help make sure the program is set up properly,” Yeske said.

“Many of our clients have started the process and many have already completed it,” he added.

In some states, veterinarians are asked to validate the SPS procedures are correctly implemented.

Veterinarians also may be needed to train others on how to test for ASF if the disease is identified in the US. “It becomes a very big biosecurity risk to go out and do testing on the positive or suspect farms,” Yeske said.

“One of the things that’s being looked at is can we do like they did with avian influenza. They had trained people who were able to go out and collect samples. This will be once we’ve had a positive, and we’re in the situation where we need to know the status of many herds,” he explained.

Next-level biosecurity

Even without a foreign animal-disease outbreak, SPS plans are valuable.

“Secure Pork Supply takes biosecurity to the next level,” Yeske said. “I think these plans are a great opportunity to review some of the procedures you’re already doing and strengthen some of the weak areas.

“I hope we never have to use it,” he added. “The reality is that I think we all have to really pay attention to this one because we’ve seen just how fast it can move with other diseases such as porcine epidemic diarrhea virus.”

For more information about Secure Pork Supply, visit



Mycoplasma elimination possible, but more difficult on farrow-to-finish sites

With the right program in place, eliminating mycoplasma pneumonia is possible on many hog farms. Farrow-to-finish sites are still the most difficult to clean up, however, reported Swine Vet Center’s Paul Yeske, DVM.

He has carried out multiple mycoplasma-elimination efforts on different types of hog farms with good success.

“The farms that are easiest [to eliminate mycoplasma] are the farms that are multi-site production, where we have a farrow-to-wean site…The herds that have all ages of pigs on site, that’s where the challenge is going to be,” he said.

Long-term herd closure

The best method for eliminating mycoplasma from a farrow-to-wean site requires herd closure to allow the animals to develop immunity and stop shedding. Research shows the disease’s causative organism, Mycoplasma hyopneumoniae, can be shed up to 240 days.

“We expose all the animals up front to make sure everybody’s exposed and immune, and then we wait 240 days,” Yeske explained. “At the end, we use some medication as a secondary step to make sure we’ve controlled everything before we bring the negative animals back in.”

The advantage of this elimination program is a short payback period of a few months, he added. A depopulation-repopulation elimination takes a couple of years to pay back the expense.

Farrow-to-finish options

Farms with all ages of pigs on one site require more time and expense to eliminate mycoplasma. A partial depopulation that empties the nursery and finishing stages for a short time is one solution, according to Yeske.

“I think there are ways we can do [elimination] on really any given farm,” he said. “It’s just finding creative ways to do it. And the depopulation-repopulation would certainly be an option.”

Complete elimination

Could mycoplasma be completely eliminated from US herds?

“I think it’s a disease that could be eliminated,” Yeske stated. He cited research that showed a low likelihood of M. hyo reinfection from neighboring finishing units.

“If you have a mycoplasma problem in your system, you likely have a system problem,” he said. “It’s not the neighborhood problem.”

Plus, the future holds new technologies like better diagnostics, new antibiotics and new testing procedures.

“Are there ways we can manipulate these tools to eliminate disease so we don’t have to deal with it?” he added. “What I’ve tried to do over time is, when something new comes out, [to determine] how could we leverage this into a new tool.”

In the past, the pork industry has eliminated diseases like pseudorabies without depopulation-repopulation.

“We had a very good vaccine with pseudorabies, and we were able to do eliminations by test and removal,” Yeske recalled. “Mycoplasma is another bug that lends itself well to herd closure and elimination.”

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Is fogging an M. hyo-elimination option for your swine herd?

Paul Yeske, DVM, with the Swine Vet Center in St. Peter, Minn., has seen repeatable success with Mycoplasma hyopneumoniae (M. hyo) elimination, along with the downstream effect of lower cost of production, better average daily gain, better feed efficiency and lower mortality. He estimates the benefit of M. hyo elimination to be in the $3 to $4 range per pig, conservatively, with some herds seeing a benefit of as much as $10 per pig when other diseases are eliminated at the same time. Now, the relatively new protocol of fogging a barn may make M. hyo elimination even more attractive.

This technology came out of the frustration of trying to evenly and efficiently expose animals to the bacterium, Yeske told Pig Health Today. Fogging allows for faster exposure to establish “time zero” for elimination, so gilts can be stable by the time they enter the sow herd.

“That reduction of time for M. hyo to spread from animal to animal in a natural way is probably the biggest advantage,” he said. Previously, Yeske would use intratracheal exposure of seeder animals, but said, “It’s a lot of work and you still have slow spread from animal to animal. Fogging has been very successful for us, although it’s still new technology and there are some lessons to learn as we go forward.”

Research needed

Fogging appears to be an effective method for M. hyo elimination, but Yeske said critical questions need to be answered on the technology:

  • How long can the inoculums be stored?
  • How long can the lungs used for the inoculum be stored if the herd is kept positive?
  • What’s the best media to use for exposure?
  • Should an M. hyo media be used, or can we use phosphate buffered saline?
  • Which products work best for fogging in terms of storage and/or the fogging procedure?
  • What’s the right dosage and volume level?

“So far it’s been very good, even with the experimental method we’ve used, but I think there’s an opportunity for it to be better,” Yeske said, adding that, “We just need to support the researchers to do the difficult work to answer these questions.”

Other methods also effective

Yeske said depopulation/repopulation is the “tried and true” method that works every time but it’s also the most expensive. It’s difficult for people to invest the money unless there are other compelling reasons, such as additional disease challenges or parity re-distribution, he noted.

The herd closure model is to keep a herd closed (no new introductions) beyond 240 days, Yeske said. Hee recommends medicating the sow herd and piglets at the end of the closure, which allowed the pigs’ immune systems to help as much as possible. Timing varies, but this model has been the most successful and has had the least amount of impact on production.

“We’ve been in the 75% to 80% success rate over time and it’s been the most repeatable system,” he said. “Generally, mycoplasma elimination has been done in conjunction with other diseases, such as porcine reproductive and respiratory syndrome (PRRS). It just adds a little more time to standard PRRS-closure and you also get rid of the M. hyo,” he said.

Another method involves whole-herd medication, without a herd closure, but Yeske said the success rate is closer to 50% when medication is done without herd closure.

“If we do limited-herd closure (150-240 days) and then medicate at the end, the process has been more successful and closer to the long-term closure success rates,” he said.

Useful tool for control or elimination

Fogging may not be a silver bullet, but Yeske said it’s a useful tool for M. hyo control, “whether you’re doing ongoing control and acclimating replacements into the herd, or you’re looking at elimination. The technology is fairly inexpensive, so it’s about having your herd veterinarian help set up the program to make sure you’re doing everything the right way.”

Yeske is often asked how likely a herd is to stay negative if a producer goes through the Mycoplasma-elimination process, especially in pig-dense areas.

“We did some research two years ago and found that lateral introductions happen, but they are rare,” Yeske said. “We saw 94% of the herds stay negative, even in pig-dense areas.”

He recommended producers and veterinarians work on herd stabilization, with consideration given to elimination if other issues are impacting the herd.