The potential inability to avoid stresses associated with extreme heat and cold allows normally endemic pathogens to demonstrate clinical signs, says Tom Fangman, DVM, Univer-sity of Missouri. By the time you observe clinical signs in grow/finish pigs, you can assume that production is being adversely affected by at least 6 percent.

Ileitis is one of the more costly diseases in the grow/finish phase. One Lawsonia intracellularis agent may be able to infect the intestinal cells of a wide variety of host species, notes Fangman. The agent may have a relatively long survival time (one to two weeks), which is why sanitation between pig groups is critical.

Appropriate antibiotic therapy administered at the greatest risk period will reduce death loss associated with the acute hemorrhagic form of proliferative ileitis. It may enhance feed conversion and average daily gain if the Lawsonia organisms are chronic in the growing pigs. Eradication is not likely, says Fangman.

Actinobacillus pleuropneumoniae is primarily transmitted by pig-to-pig contact or by moisture droplets within short distances. Antibiotic therapy is effective in clinically affected animals only in the disease’s initial phase when it can reduce mortality, notes Fangman. Using a combination of injectable and oral medications early in an outbreak often yields the best results.

Controlling environmental factors such as temperature and ventilation and the use of solid partitions between pens may minimize the development and severity of disease. Continuous or pulse medication can be practiced for short periods, says Fangman. All-in/all-out, segregated early weaning and large air spaces with separation between pig groups will considerably reduce infection risks.