Actinobacillus Pleuropneumonia (APP) is a swine disease that has plagued producers for many years. It hits a group of pigs suddenly, and the death loss can climb quickly.

APP is especially costly to feeder pig finishers who lose a large number of pigs, virtually eliminating any profit.

This situation has led to a lot of pressure within the industry to produce APP-free animals. Breeding stock companies have done an excellent job of freeing their multiplier herds of this disease. There are very few replacement gilts sold today that are APP positive. However, there are still plenty of APP-positive herds producing pigs.

The frustrating thing about APP is pigs can look perfectly normal one day and be dead the next. APP-positive pigs can also be finished without showing any signs of disease. There appears to be a stress factor that triggers the onset of this disease and high death loss.

APP-positive pigs have little market value. Last fall and early winter, when there was a plentiful supply of feeder pigs, and feeder pig and weaned pig prices were low, APP-positive weaned pigs were selling for $5 or less. This encouraged purchase of these pigs for finishing to make a profit in a down market. In some cases these “opportunity pigs” were successful and in others they were not.

Case Study No. 1

The first farm is a 2,400-sow, wean-to-finish barn filled with 4,800 segregated early weaned pigs from an APP-positive farm. Double loading the wean-to-finish barns is a common practice to better utilize space and accommodate pig flow.

The pigs were of good quality and averaged 12 lb. They arrived on a cold December day. The barn was not adequately prepared with zone heat, and some pigs were chilled.

Three weeks after arrival, death loss increased. Postmortems and laboratory diagnostics indicated pigs were dying from APP. All pigs were injected with ceftiofur, and tilmicosin was added to the feed at 272 g./ton for 21 days. Tilmicosin works best as a disease preventive; however, it can be difficult to know when pigs will break with APP.

Death loss continued for a few days after the outbreak, with 6% succumbing by the fourth week. The rest of the pigs recovered and did well until the barn inventory was reduced to 2,400 head, seven weeks after the pigs arrived.

Two weeks later, the barn broke again with APP and death loss quickly climbed to 18%. The pigs were injected with ceftiofur and death loss stopped.

The high death loss, high medication cost and low hog market made it difficult for these pigs to be profitable. Double stocking and the lack of a uniform, comfortable area for the pigs contributed to stress and the onset of APP.

Case Study No. 2

Three thousand APP-positive weaned pigs were purchased and placed in four different nurseries. The nurseries were all mechanically ventilated with excellent management and environmental control. Managers understood the controlled environment and recognized when the barns needed adjustment to improve air quality and pig comfort.

The pigs were started on oral tetracycline in the water and a preventive level of tilmicosin at 181 g./ton for three weeks. The treatment was repeated three weeks later.

The pigs closed out of the nursery at just under 3% death loss. These pigs were vaccinated for APP seven days before leaving the nursery, and performed well in the finishing barns.

Tilmicosin was used in the finishing feed at 181 g./ton for two more three-week periods to prevent clinical signs of APP. These pigs went into well-managed finishing units, where death loss topped out at 4%.

This case is an example of how APP-positive pigs can perform well when placed in a good environment, with proper management and use of preventive pulse medications.


Producers can profit from APP-positive pigs with proper management, antibiotic treatment and reduction of environmental stressors.

Production costs will be higher due to increased antibiotic expense. But performance may more than justify the added expense. Tips to successfully raise APP-positive pigs:

  • Manage the environment to reduce stress.

  • Use tilmicosin in the feed for a preventive protocol in accordance to your veterinarian's recommendations.

  • Consider strategic use of immunizations to effectively reduce the incidence and severity of APP pigs in certain situations.

  • Quickly identify and respond to an APP outbreak to stop death loss quickly and keep losses low.

Raising APP-positive pigs can be risky. It's crucial to work closely with your veterinarian to develop and implement effective control and treatment protocols to shift the odds to your side when finishing these types of pigs.