Ileitis, or proliferative enteritis, continues to cause disease problems in grow-finish and breeding herds. It is caused by Lawsonia intracellularis, a bacteria that affects the terminal part of the small intestine, or ileum.

Clinical signs in grow-finish range from slight diarrhea to an acute outbreak causing sudden death. Results are added disparity in pig weight and lower overall pig performance.

In the breeding herd, ileitis can be a challenge when naçve gilts exposed to the bacteria break with the disease. This scenario often occurs right at breeding time. Sick gilts don't cycle well and reproductive performance is off.

Disease control varies based on disease severity and pig flow.

Case Study No. 1

A client purchased 600 weaned pigs/week from a 1,500-sow, breed-to-wean operation. Pigs were placed in a 1,200-head nursery for eight weeks and then moved to the finishing barn. Health was excellent and death loss out of the nursery was under 2%.

Typically, the pigs performed well in finishing. Some finishing group closeouts achieved 2% or less death loss, while others occasionally closed out at 3-4%. Most losses in these higher-percentage death loss groups were in the last 30 days of finishing.

Postmortem examinations showed these pigs were performing well, but were very pale and had a large amount of blood in the small intestine. The ileum appeared thickened and lab work confirmed the diagnosis of acute proliferative enteritis (ileitis).

For ileitis breaks, we have had success using two approaches — vaccinating the pigs, or pulse-medicating with a feed-grade antibiotic two weeks before the typical onset of the problem.

In this case, performance wasn't much different in terms of feed efficiency or average daily gain between the groups that had high death loss and low death loss.

The producer elected to treat with feed-grade antibiotics two weeks prior to the expected onset of clinical signs. Treatment regime was 100 g. of tylosin/ton of feed for seven days. This program decreased late finishing death loss and cost about 25¢/pig. The producer felt he only needed to reduce death loss by two pigs/1,200 to break even, and he felt the improvement far exceeded that.

Case Study No. 2

This producer was 50% owner in a 1,500-sow, breed-to-wean farm and also received 600 pigs/week. Pigs were mixed in different nurseries throughout the area and then combined into several 1,200-head finishing barns.

Performance and health were excellent. But the pigs were consistently breaking with diarrhea, and death loss increased as pigs reached 120 to 140 lb.

Postmortems and lab results confirmed the presence of ileitis. We discussed different control options. The pigs responded well to individual treatment with injectable tylosin and the inclusion of tylosin in the water.

There were no further problems, but it appeared that this outbreak was affecting overall performance and slowing growth.

The producer elected to try an oral ileitis vaccine to see if he could prevent the problem. We recommended vaccinating pigs just before leaving the nursery at 10-11 weeks of age. Vaccination reduced most of the problems, but some finishing sites still occasionally broke with ileitis.

However, the producer admitted that he was only using a half dose of vaccine to save on costs. We recommended that he go to a full dose, and the problems were corrected.

Case Study No. 3

An 800-sow, farrow-to-wean operation had gilts that consistently broke with ileitis shortly after introduction into the gestation barn. The gilts would go to a holding pen for 60 days, be bred, then were grouped in the gestation area based on breeding dates.

Approximately 3-4 weeks later, about 30% of the gilts would break with a bloody diarrhea that would eventually respond to injectable tylosin. These gilts would recover, but they were much thinner. The lost weight resulted in smaller gilts at farrowing.

We advised the producer to vaccinate gilts with the oral ileitis vaccine as they came into the isolation barn, which has stopped outbreaks of clinical ileitis in replacement gilts.


Ileitis has been around a long time and has not changed much. Treatment and prevention methods can be quite effective, but need to be administered correctly and at the proper times.

Be sure to obtain an accurate diagnosis before implementing any control programs, because there are other diseases that look like ileitis, such as salmonellosis, hemorrhagic bowel syndrome, stomach ulcers and intestinal torsions.

Working with your local veterinarian to determine the cause and best course of action is always dollars well spent.