Managing high health pigs coming into high dense areas

​​​​​​​In high density locations, producers need to assume last batch had PRRSV, schedule a realistic break between groups for sanitation.

Ann Hess, Content Director

July 29, 2022

6 Min Read
Placing pigs (1).jpg
National Pork Board

When it comes to successful pig production, it is often said the one who "makes the least number of mistakes typically is the winner." However, Clayton Johnson points out starting with healthy pigs is an excellent first step, especially if those pigs are heading to a pig dense region.

"It's health typically, that's the biggest barrier that we run into, and I think if we start with a good healthy weaned pig that's a great first step," says the Carthage Veterinary Service swine practioner.

That means starting with heavy wean weights, minimal variation and no cough.

"I think if you're putting pigs into a pig dense region you want to make sure No. 1 the site isn't contaminated with PRRS (porcine reproductive and respiratory syndrome) and they get it from the site," Johnson says. "I know that sounds obvious, but I would tell you that doing some serology of pigs in Iowa early in my career, all of the pigs in central Iowa are going to get PRRS — all of them. I don't mean some of them, I mean all of them."

In high density locations, Johnson says producers need to assume the last batch had PRRSV and to schedule a realistic break between groups for sanitation.

"We're always tight on space in the summer, maybe not as bad right now as industry dynamics are a little bit unique but generally, we get really tight on space, and we refill the barns as fast as possible," Johnson says. "I'm not saying that you need three weeks of downtime but asking somebody to turn over a wean-to-finish site in three or four days is not realistic."

Pig space cleaning needs to include the hallways and loadouts and should first be dry cleaned, then sanitized with detergent or degreaser, pressure washed with hot water, inspected and disinfected. The office and supply storage area should also be cleaned.

"Inspect what you expect and try to get that first inspection done before they're done washing," Johnson advises. "Don't wait until they're done with the entire site and then go tell them they're going to redo everything. If you can get in there when they're done with the first room or the first barn, go in and show them the areas where they're commonly missing because they're going to miss the same areas in the next barns."

Johnson suggests not applying a liquid disinfectant that will just drip into the pit. No matter what type of disinfectant is used, it needs contact time.

"If it's just a true liquid that sprays onto your walls and drips directly into the pit, where's the contact time happening?" Johnson says. "You're literally wasting your money so use a foaming applicator and get some sort of cling where you're actually going to get contact time."

After the office and supply room, the veterinarian says don't forget about the bolt gun and mortality supplies area.

"Most wean-to-finish sites are going to have a bolt gun in some way shape or form," Johnson says. "If the sites contaminated, guess what else is probably contaminated — the bolt gun."

To maintain a high health status, farm staff must be educated on biosecurity and the biosecurity plans should be specific for that farm. Johnson says a lot of non-compliance is non-understanding.

"We have a lot of turnover in finishing barns and one of the things that I would tell you is while every pig is going to get PRRS during the wean-to-finish period in a high-density area, they're not going to get it in the first four to six weeks," Johnson says. "There's something about the newly weaned pigs' respiration pattern that they're not very susceptible to aerosol transmission."

He references a recent study where at the end of closeouts they looked at pigs at the four-to-six-week post-weaning time and none of them had been laterally infected at that point.

"We've got a fighting chance to get those pigs started, to get them to feeder pigs, 30-40 pounds, where they can handle the infection a little bit better, if we don't walk it in, but a lot of times in wean-to-finish in high dense areas, people just assume it's going to happen," Johnson says.

Biosecurity has the highest value early in the growing period, Johnson says. Employees should be dedicated to just that site. Only the field supervisor and veterinarian should visit the site. All supplies should be disinfected and into the site before the pigs arrive. Finally, a mortality removal clean-dirty line needs to implemented and managed.

"How many farms do we go to, and you go to the bench, and you see shoes that are three feet away from the bench? That is a sign they don't know what they're doing," Johnson says. "We've done a great job of teaching them the SOP, see bench, take off shoes at bench, but why do we take off the shoes at the bench? How do we make sure that our socks don't get contaminated and waste the value of the bench? Explain those things and see the light bulbs go on. When they understand the concepts they'll make better decisions when you're not there."

Production sites also need to have a contingency plan for a PRRS outbreak. PRRSV modified live vaccines have shown repeated value in decreasing mortality and viremia volume and duration, while increasing average daily gain, Johnson says. However, PRRSv MLV vaccines require 28 days to develop protective immunity and ideally PRRSV MLV should be administered to pigs 7 to 14 days post-weaning.

"Get those vaccines in early because we need about four weeks after we give the vaccine, before the pig really has any sort of robust immunity," Johnson says. "That's going to make a difference when the pigs do get infected but think about that timeline. Pigs don't typically get infected in the first four to six weeks post-weaning so if we get them vaccinated one to two weeks post weaning, they can build that immunity and have the immunity for when they inevitably do see that wild-type field virus."

Finally, a contingency plan needs to contain a biocontainment SOP. That means making sure other sites don't get contaminated. This involves updating a "pre-fill" plan once diagnostics come in on a PRRS positive site with downtimes and flow charts for employees and visitors, as well as for transportation and the feed mill. Communication also needs to happen with neighbors and site swaps should also be considered.

"Where are we going to put the fallback pigs? Where are we going to put the small pigs that we sorted off?" Johnson says. "Make that part of the pre-fill plan."

About the Author(s)

Ann Hess

Content Director, National Hog Farmer

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