Real-world Ileitis Strategy Pays Off

When your recommendations can affect nearly 2 million pigs across several states, you tend to do your homework. That's the case with Steve Hargis, president and chief executive officer of South Central Management Services in Wells, Minn., who spends a lot of time keeping up with the latest in swine research from all over the world. Yet, when his clients need practical answers to costly problems like subclinical ileitis, he often finds some of the best answers close to home.

While porcine reproductive and respiratory syndrome and porcine circovirus associated disease are keeping most producers up at night, Hargis says you can't afford to overlook the more "invisible" diseases like subclinical ileitis. "It's always important to control the diseases that you can, but rising feed prices make controlling a challenge like subclinical ileitis all the more critical because it's a year-round problem."

Hargis" strong position on the issue stems from his first-hand experiences with producers and veterinarians. He's seen the health, performance and economic damage that subclinical ileitis can cause all the way to market. And he's not alone; a 2005 study found subclinical infections reduced average daily gain by 38 percent and cut feed efficiency by 27 percent over a three-week period.

While ileitis" negative economic impact has increased with today's ethanol-driven feed prices, most producers already have some idea of its cost. In the 2003 National Swine Disease Impact Study, sponsored by an animal-health consortium, producers reported that the average cost of clinical ileitis was $5.34 per head, with subclinical ileitis costs averaging $5.19 per head.

"From my perspective, no herd is safe from Lawsonia intracellularis," Hargis says. "Even very clean herds are at risk, so establishing a control-management plan for subclinical ileitis is wise."

Tests and trials

Hargis doesn't take chances with his clients" pigs, especially when it comes to health, performance or profits, which is why he advocates the use of herd diagnostics. However, he realizes that even if a herd tests negative for Lawsonia intracellularis at one point in time, the risk remains all the way to market.

"About three to four years ago, we began intensive diagnostic testing for Lawsonia intracellularis exposure in the nursery using fecal tests," he says. "We found shedding occurring in 9-week-old pigs so we began using Tylan at 100 grams per ton for 21 days in the first grind-and-mix ration."

After the initial three-week dosage, Hargis says many of his clients now use 40 grams of Tylan all the way to market. "With this approach, we've seen very few outbreaks, including late outbreaks."

Hargis says it pays to keep the pig's intestinal tract as free as possible from costly pathogens. "We think using an in-feed medication keeps Lawsonia levels low. This helps set up the pig's gut for success in terms of high health and performance."

As a result of his ileitis-control efforts, Hargis says cull rates among grow/finish pigs have declined by 1.5 percentage points during the last two years. "We figure we've seen a return of $4.85 per head with our current protocol." 

Hargis always advises clients to source high-health pigs from a sow farm with a strong health history. He also emphasizes that proper stocking density and ventilation, as well as thorough biosecurity and sanitation practices, are important steps to control diseases.

He adds, "We haven't found the magic bullet to eliminate Lawsonia, but our current strategy for controlling subclinical ileitis is working well."

Sizing up a hidden threat

According to a collaborative study between the University of Minnesota and Elanco Animal Health, most of today's finishing pigs are infected with Lawsonia intracellularis and are suffering from subclinical ileitis. Researchers suggest that producers review their control strategies for this pervasive disease based on this new data.

  • 94.3 percent of pig flows that showed no clinical signs of ileitis tested positive for Lawsonia intracellularis and were classified as having subclinical ileitis.
  • In the majority of herds, the rate of seroconversion is high between 12 and 18 weeks of age, yet 69.6 percent of pig flows found seronegative for Lawsonia intracellularis at 18 weeks were later found positive between weeks 21 and 27.
  • Disease status and seroconversion rates remain highly variable from farm to farm.
  • Clinical signs of ileitis are a poor indicator of infection and subclinical ileitis within a herd.

On-farm trial offers insight

In an Iowa-based, wean-to-finish trial of 4,235 pigs, Steve Hargis, president and chief executive officer of South Central Management Services, Wells, Minn., carefully reviewed the results of two strategies to prevent and/or control ileitis in his clients" herds.

As a result of controlling ileitis, pigs receiving a feed premix (Barn A) outperformed those given a water-based product (Barn B) in several key production measurements, including overall profitability.

Hargis explains that some of the revenue difference between the two groups is due to pigs in Barn B becoming infected with Actinobacillus suis during the trial. However, he says the numbers are statistically significant and reiterate performance differences seen in previous trials.

"We are confident that the ileitis-weakened pigs in Barn B had a compromised immune system that opened them up to the Actinobacillus suis.



Barn A


Barn B


Average Daily Gain


1.77 lbs.


1.59 lbs.


Feed Efficiency






Deads, Culls






Net Revenue








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