Producers continue to battle porcine reproductive and respiratory syndrome (PRRS) and porcine epidemic diarrhea (PED) on the farm. When it comes to layering a biosecurity approach to protect their sow herd, more and more farms are including a feed mitigant as another line of defense.
“I recommend a feed mitigant in every sow diet for the entire year,” says Scott Dee, DVM, and emeritus, University of Minnesota and Pipestone Research. “There’s so much data now on the risk of feed moving viruses. To me, it’s a no-brainer. Just put it in and keep it in. There’s a little bit of a cost to it, but in our three-year Pipestone project, once we started using feed additives, it helped reduce PRRS incidence down below 10%.”
Known for his extensive research in nutrition and health, including feed biosecurity, Fredrik Sandberg, senior director of research and development at McNess, asked Dee to come out of retirement to test FeedARMOR, a dry feed supplement recently launched at the 2025 World Pork Expo.
“The feed mitigation space is quite saturated with 15 to 20 products of varying quality and varying price,” Sandberg says. “The majority of products cost between $10 and $20 a ton, which is pretty expensive when you’re trying to do insurance. They also have very different efficacy.”
The “king of the hill” has been formaldehyde. Early work done by Dee, Kansas State University and other entities has shown this product’s effectiveness at killing viruses in feed and stopping infection of animals, Sandberg points out. However, safety and handling concerns have caused some feed mills to stop putting in the equipment needed to include this product in feed.
“We were tasked by our sales team to develop a solution that could be equal level of efficacy at the same price point,” Sandberg says. “Using formaldehyde is roughly about $6 a treated ton of feed for the product, plus about an extra $2 a ton from having to upregulate amino acids and things that the formaldehyde destroys. It is the cheapest and most effective. There’s a reason why people use it.”
McNess had an existing product in this space and had done a lot of research. Sandberg and his team took some of that old research and tried to develop it to come up with some prototypes. They finally arrived at FeedARMOR.
“FeedARMOR is a very stable, good-flowing product, and can be used as low as 2 lb. per ton, compared to liquid formaldehyde that is 3 to 7 lb. per ton,” Sandberg says. “In terms of price, FeedARMOR is $4.70 a treated ton of feed. That’s just the cost of the product. Two lb. per ton takes up a lot less space in the diet. If you have a minimum energy constraint on your diet, if you’re using mitigants that are 6 to 10 lb. per ton, they are taking up some energy space in the diet, so there’s additional savings there. FeedARMOR is basically $4.50 a ton of treated feed, making it very economical.”
But Does It Work?
When Dee was approached by Sandberg to test this product in Pipestone’s BSL2 facilities using his “ice block challenge” model, he says he was intrigued enough to come out of retirement and run the five-room trial.
In one room, pigs ate feed that was challenged with virus but with no feed mitigation. In the next room, the pigs ate feed that was challenged with virus and treated with formaldehyde. In the other three rooms, the pigs ate feed challenged with virus and treated with FeedARMOR at 2 lb. per ton, 4 lb. per ton and 6 lb. per ton.
“I made up 1 lb. blocks of ice that had Seneca Valley Virus A, PRRS and PED each at equal concentration,” Dee explains. “It’s like a nuclear reactor – a huge virus bomb. We always change the strains to make sure they’re the most recent strains.”
More specifically, this study’s recipe included the PRRSV 1-4-4 Lineage 1C strain, Dee says. It’s important to always have the most relevant variants.
“We then put the feed in the bins, got the pigs in the room, climbed up the bin ladder and threw the ice block in the bin,” Dee explains. “Then, we just let Mother Nature take its course. The feed gets augered into the room. Pigs eat the feed.”
After that, Dee tested the feeders to make sure that the feeders were positive and the virus got into the room. Then, they obtained oral fluids on the pigs to make sure the pigs contracted the virus. They also watched for clinical signs and took samples for oral fluids to see if there were any more infections.
“As you’d expect, in the room with no mitigation, we had very nice infection,” Dee says. “We had blisters on the nose and had to bring the state vet in to clear that it wasn’t foot-and-mouth disease, but of course it was Seneca Valley Virus A. We also had PRRS and PED, so the challenge model really worked.”
Sometimes, it doesn’t work, he adds. Dee says he gets nervous about this part because there have been times when he couldn’t get the virus into the feed and into the pigs.
“This time it got into the control room. We found it in the feeder. We found in the oral fluids,” Dee says. “But interestingly enough, in the other four rooms we found the virus in the feeder by taking a Swiffer of the pan, but we couldn’t find it in the pigs. We couldn’t find any oral fluids that were positive for either virus during the whole trial period.”
Dee says the ice block challenge resulted in virus everywhere in the room with no treatment, but they found no virus present in the pigs in the rooms with treatments. Dee says this is the first time a product had performed at the level of the industry’s gold standard – formaldehyde.
“It’s intriguing that a new product might have that ability to match the performance of formaldehyde,” Dee says. “Other products I’ve tested over the years do a pretty good job, but you can always find virus in the pigs. In this trial, we couldn’t find any virus in the oral fluids – that’s a novel observation. Nothing’s ever kept up with formaldehyde, but FeedARMOR did.”
What Do the Pigs and Feed Mill Operators Think?
One of the issues with organic acid-based products is that several of them negatively impact feed intake, Sandberg says.
“That’s been published,” he adds. “A client was recently sharing concerns about one of their sow farms using an organic acid product and the pigs having decreased intake. We actually have data to show that FeedARMOR improves feed intake, which is a big deal in lactation diets.”
In addition, the product has shown no degeneration of vitamins or amino acids. Sandberg also points out one more advantage of the product when it comes to mode of action. Some of the major organic acid-based products on the market today are around a 2 pH level.
“A pH of about 2 is halfway between lemon juice and gastric acid juice,” Sandberg say. “It’s a very high level of acidity. We’re very excited that FeedARMOR, even though it has a formic acid component, only has a pH of 3.5, which sits right between apple juice and tomato juice.”
Acidic products can also have a negative impact on metal feed mill equipment.
“Metal and acids don’t go together. We know cases where there has been erosion or damage to feed mill equipment because of these high organic acid compounds,” Sandberg says. “With many of them, they’re adding 10 lb. per ton while we’re only adding 2 lb. per ton of a product that has much less acidity. When you do the math, that’s a pretty big game changer.”
In Dee’s mind, the biggest takeaway from this trial is that there is a product out there now that matches formaldehyde’s performance.
“This product also doesn’t have any of the issues with formaldehyde handling. It doesn’t require OSHA and EPA oversight on the mill like formaldehyde either,” Dee adds. “It’s a new kid on the block, and it was pretty impressive in its first time around.”
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