Pneumonia in pigs, an inflammation of the lungs, is a widespread and economically impactful disease in the swine industry. The condition is not caused by a single agent but results from complex interactions between various pathogens and environmental factors. This complexity makes both management and prevention a continual focus for producers aiming to maintain herd health and productivity.
Primary Causes of Swine Pneumonia
Swine pneumonia is initiated by infectious agents, primarily categorized as either bacterial or viral. These pathogens can act alone or in concert, creating a more severe respiratory disease. They spread from pig to pig through the respiratory route via aerosols from coughing or direct nose-to-nose contact.
Among the bacterial causes, Mycoplasma hyopneumoniae is a frequent instigator of Enzootic Pneumonia. This bacterium damages the cilia in the pig’s airways, impairing the lung’s natural clearance mechanism and making the animal susceptible to other infections. Other bacterial pathogens include Actinobacillus pleuropneumoniae (APP), which causes a severe and often fatal pneumonia, and Pasteurella multocida, which acts as a secondary invader.
Viral agents are also primary drivers of pneumonia. The Porcine Reproductive and Respiratory Syndrome (PRRS) virus suppresses the pig’s immune system, opening the door for bacterial co-infections. Swine Influenza Virus (SIV) directly attacks the respiratory tract lining, causing inflammation that can lead to pneumonia or create an environment for secondary bacterial growth.
Recognizing the Signs of Pneumonia
Identifying pneumonia in a swine herd involves observing clinical signs that can vary from subtle to severe. A common initial sign is a persistent, dry cough, sometimes described as “barking,” which is more noticeable when pigs are disturbed. This can be an early indicator of a developing respiratory issue within the herd.
Labored breathing, often called “thumping,” is characterized by visible, exaggerated abdominal movements as the pig struggles to draw air into its compromised lungs. This is frequently accompanied by a fever, lethargy, and a general disinterest in feed and water. A reduced appetite signals illness and also contributes to poor growth rates and weight loss.
An increase in the overall number of animals coughing is a clear sign of a herd-wide problem. In some cases, pigs may exhibit discharge from the eyes or nose. Severe cases, particularly with aggressive pathogens like APP, can lead to rapid deterioration and even sudden death, underscoring the importance of daily observation.
Treatment and Management Strategies
Once pneumonia is suspected, securing a diagnosis from a veterinarian is the first step toward effective management. Attempting to treat without a proper diagnosis can be ineffective and may lead to increased costs and animal suffering. A veterinarian can determine the likely pathogens and formulate an appropriate treatment plan.
Treatment strategies involve a combination of antimicrobial medications and supportive care. Antibiotics are effective only against bacterial infections, not viral ones. When a viral infection is the primary cause, antibiotics may still be used to control secondary bacterial invaders that take advantage of the pig’s weakened state. Anti-inflammatory drugs can also be administered to reduce fever and lung inflammation, encouraging the animal to eat and drink.
Supportive care is a large part of helping pigs recover. This involves moving sick animals to a separate, isolated pen where they can be monitored closely without competing with healthy pigs. This hospital pen should be clean, dry, and well-bedded to protect pigs from drafts. Ensuring constant access to fresh water and palatable feed is also fundamental for recovery.
Prevention and Control Measures
A proactive approach focused on prevention is the most effective way to manage pneumonia. This strategy is built on vaccination, biosecurity, and environmental control. Vaccinations are available for many common pathogens that cause pneumonia, including Mycoplasma hyopneumoniae, PRRS virus, and SIV. Implementing a vaccination program tailored to the farm’s specific risks can significantly reduce the disease’s severity and incidence.
Strict biosecurity protocols are fundamental to preventing the introduction and spread of pathogens. A core practice is the quarantine of all new animals before they are introduced to the main herd. The all-in/all-out (AIAO) system, where an entire barn is emptied, cleaned, and disinfected before restocking, is highly effective at breaking disease cycles. Controlling traffic onto the farm, including people and vehicles, also minimizes the risk of introducing new infectious agents.
Managing the pig’s living environment plays a direct role in preventing respiratory disease. Proper ventilation is needed to control humidity, remove harmful gases like ammonia, and reduce airborne pathogens. Maintaining appropriate stocking densities prevents overcrowding, which can increase stress and facilitate disease transmission. Ensuring pigs are in their thermoneutral zone helps minimize stress and allows their immune systems to function optimally.