Getting baby pigs away from the sow before maternal antibodies run out reduces the odds that they will contract diseases she might carry. Multiple-site production, along with segregated early weaning and other technologies, can limit pathogen transfer between groups.

But multiple sites are no cure-all. Only proper management and a commitment to biosecurity make it work. To start, you have to follow strict isolation and all-in/all-out pig flow protocols.

What makes a production scheme a multiple-site operation? Tom Fangman, a University of Missouri veterinarian, suggests sow herd facilities, nurseries and finishers that are 200 yards from each other and 1,000 yards from any neighboring pigs is legitimate. Other sources may argue distances, but the critical issue is that pigs don't share air.

But multiple-site production is more than distance, Fangman warns. It's about biosecurity measures as well.

Multiple sites demand separate workers or at least shower facilities on each site. Limiting mutual vehicle traffic between sites is another key. Otherwise, you end up with pigs on two or three sites but continue to cross-contaminate between them. You simply won't get the benefits multiple sites promise.

Biosecurity starts with pig flow, people flow and truck traffic. "If you can't make those things work on a single site, multiple sites won't make it better," says Randy Bush, a Flora, Ind., veterinarian.

"It takes a higher level of management to run multiple sites," he adds. Without biosecurity, adding units on a second site will cost money without the payoff. "If you aspire to that higher level, multi-site production is a great tool."

Not every operation has the means to set up multiple sites. You may not have the land base, buildings may be too expensive or you may not be raising enough pigs to justify the cost. Multiple sites tend to work best with 1,200 or more sows, says Kirk Clark, Purdue University veterinarian.

But Bush works with smaller operations that have embraced the technology. "Typically, those who employ multiple sites are technology adopters – usually growing operations," he says.

What if you can't build an off-site nursery? Do you throw up your hands on better health status? No. You make a commitment to biosecurity to get the best performance you can, Fangman says.

Start by identifying the pathogens in your operation, he says. Have your veterinarian necropsy a few pigs, do routine post-mortem exams and serological evaluations of pigs from all production phases. Then determine the correct weaning age and pig flow for your herd. (See table at right for weaning ages for various diseases.)

Fangman cites Boonville, Mo., producer Leroy Vollmer as an example. Vollmer has 340 sows on a single site with his nursery just 30 feet from the farrowing house. That's considered the same air space, Clark points out.

Data suggests reduction of bacterial cross-contamination requires a distance of 200 yards. For airborne viruses, that jumps to two miles or more.

When you can't control airflow between units, Bush suggests focusing on what you can control: pig flow, people movement and truck traffic.

Fangman notes Vollmer has adopted a biosecurity plan to limit the chance of pathogen transfer between buildings. (See sidebar on Vollmer's biosecurity protocols.) Still, Vollmer wanted to compare his on-site nursery performance to an off-site nursery.

He and Fangman designed a trial. They took pigs weaned at 18 to 21 days to an empty off-site nursery 25 miles away. They kept similar pigs in the nursery 30 feet from Vollmer's farrowing unit.

Performance was the same for both pig groups. Age to market tallied 170 to 180 days. Vollmer notes his genetics may not be capable of doing much better.

"We were encouraged with the trial's results," Vollmer says. "We did as well on-site as off-site. It shows we're doing something right at home."

Sow health status is key. "What makes our situation work is that we have a pretty clean sow herd," Vollmer notes. "Other than Strep. suis, we don't have any major health problems." That lets him wean pigs later without them having to face overwhelming disease challenges.

"Vollmer understands the concepts of maternal antibodies and of weaning pigs at an age when those antibodies are still high," Fangman says. If another disease should creep into the herd, Vollmer would alter his weaning age to limit the threat.

So consistent biosecurity can be accomplished on one site.

"I could site a 1,200-sow operation on a section of land," Clark says. "I'd put the isolation facility furthest east (assuming a predominant westerly wind)." Farrowing and gestation units would go 200 yards west of it. Finishing units would come 200 yards west of that, with the nursery 200 yards further west.

If you start with healthy sows and keep workers from moving into a unit west of the one they've been in, this arrangement can work well, Clark says.

One operation he works with looks like a continuous-flow setup. But is run like a two-site operation. "The only way to get from one facility to another is to shower and change your boots and clothes," he explains. Pigs move from the farrowing house to the nursery through a chute. Preweaning mortality is less than 1 percent. "Everything is working as it should, and it's all one site," he notes.

The crucial factor is to maintain a biosecurity system. Even a multiple-site operation will find that's difficult. In fact, large operations may have more trouble keeping everyone tuned into that message. "The larger the labor force, the more critical day-to-day implementation of biosecurity protocols," Bush says.

Multiple sites alone don't protect your pigs from disease challenges. In a pig-dense area, moving the nursery a mile from your sows may simply place it a mile closer to your neighbor's pigs. That may be a step backward.

How do you decide whether multiple-site production fits your needs? It depends on your long-term plans, says Clark. If you're in the pork business for the next decade, investing in multiple sites usually pays off. If you plan to quit in five years, why spend the money?

Fangman notes it takes a minimum of seven years to pay off a new unit. If you can't do that, Bush advises making the best of your present situation.

Bush offers this litmus test: If performance predictability is critical to your success, multiple sites may be the route for you. If you can afford an occasional setback or slightly-lower-than-maximum growth (offset by the $165-per-pig-space cost of a new off-site nursery), you don't need multiple-site production.

Bush has clients with single sites who routinely get performance as good as or better than clients with multiple sites.

Vollmer is making it work too. Fangman says it's optimizing health status rather than trying to maximize it.

"On this farm, under these conditions, we've probably optimized the health status," Fangman says. "To maximize it, we would have to move the nursery off-site."

That may happen down the road. Vollmer is considering moving to 400 or 600 sows. When that happens, he may add an off-site nursery.

He plans to add shower-in/shower-out protocols to his system. That facility will sit between the farrowing and nursery units. That should help ensure no one circumvents the biosecurity plan Vollmer is committed to maintaining.

That commitment is the first step to the best possible herd-health status no matter where your facilities sit.

How far is far enough? Mike Muirhead, a European veterinarian, offers the following suggestions for optimal site separation distances. His point here is to prevent the airborne spread of these diseases.

Tom Fangman, University of Missouri veterinarian, cites fellow swine practitioner Scott Dee's suggested distance for porcine reproductive and respiratory syndrome virus. Muirhead didn't include that in his original recommendations. The distances are not scientifically proven but are based on current available data.

Mycoplasma hyopneumoniae 2 miles
Pseudorabies virus Up to 50 miles
Strep. suis 2 miles
TGE 300 yards
APP 300 yards
Swine dysentery 300 yards
Atrophic rhinitis 300 yards
PRRS 200 yards

A Single-Site Biosecurity System

While every farm is different, the concepts of biosecurity are the same. Managing pig, people and vehicle flow can lower the odds pathogens will spread from one group of pigs to another.

Distance between pigs (at least 200 yards) makes that easier, but you may not have that luxury. Here's an example of the biosecurity rules that Leroy Vollmer uses in his Boonville, Mo., operation.

1. Clean all rooms thoroughly with a high-pressure washer and disinfect with a broad-spectrum product. The rooms set idle 24 to 48 hours between pig groups to let them dry and allow any pathogens to dissipate.

2. Limit age spreads within pig groups to minimize cross-contamination from older pigs to young pigs.

3. In farrowing and nursery units with multiple rooms, start chores by addressing pigs of the highest health status first then continue to the lowest health-status pigs.

4. Assign workers to specific areas. For example: One employee will work in the farrowing room only. Another will work only in the nursery. Two others will feed breeding and gestating animals, heat check and breed sows.

5. Workers will wear clean clothing and boots to the farm each day. Once a worker comes in contact with lower-health-status pigs, he or she cannot return to pigs of higher health status until clothing and boots are cleaned and sanitized.

For example: A clean set of coveralls and boots is available for any worker who must enter the nursery after entering the farrowing room. A washer and dryer are available on site for cleaning contaminated clothes.

6. Foot baths are located inside the doorways of the cold nurseries to avoid introducing pathogens if a worker has to step into the alley to observe pigs. Brushes are kept by boot baths to remove organic material from boots before entering a building.

Workers are to sweep and wash the alley in the hot nursery after each room is filled.

7. Vollmer plans to build a central office with showers for workers to use before they travel from one production area to another.

8. Rodent control includes gravel strips surrounding the perimeter of all buildings and a baiting program. He calls professional exterminators if rodent problems increase.

9. Only on-farm vehicles are allowed at the site. Exceptions are an electric company truck that hasn't been to other farms and a truck to deliver soybean meal. Lime on the driveway helps reduce the potential of pathogens coming in on vehicle tires.

10. Market hog load-out facilities are located at the end of each finishing barn. Washed trucks come in on Mondays to load hogs. If the truck arrives with bedding or with manure residue, it's not allowed near the barn. It must be cleaned or another truck is brought in.

11. Dead animals are placed in one of two composters. One, on the south side of the road, contains sows and piglets. The other, on the north side of the road, contains grow/finish hogs.

12. Farm visits are limited. Visitors must wear clean clothing and boots.

13. The farm is negative for the porcine reproductive and respiratory syndrome virus, and workers must avoid exposure to any pigs that may be exposed PRRS.

14. Replacement animals are isolated in a building south of the office for no less than 60 days. They are exposed to farm pathogens via a feedback program including fecal matter from farrowing sows or finishing hogs. Vollmer conducts blood tests when the animal arrives and 45 to 50 days into the isolation period.

Here you'll find suggested weaning ages to limit disease exposure from the sow to her piglets. These numbers are not absolute. Some diseases may spread despite early weaning practices.

Pseudorabies 21 days or less
APP 21 days or less
Mycoplasma hyopneumoniae 10 days or less
Pasteurella multocida 10 days or less
Haemophilus parasuis 14 days or less
PRRS 10 days or less
Salmonella cholerasuis 12 days or less
TGE 21 days or less
Source: Hank Harris, Iowa State University