Many pig farmers face this problem: pigs develop coughing, labored breathing, and abdominal breathing. After injections or medicated feed, they soon stabilize and resume eating, but three to five days after the medication is stopped, the coughing and breathing difficulties flare up again. A few pigs die each day, and repeated outbreaks continue to cause losses.
Many farmers go straight to medication for porcine contagious pleuropneumonia. In cases of porcine contagious pleuropneumonia alone, a full course of treatment and suitable environmental conditions, along with appropriate medication, can usually bring the situation under control, with long-term recurring deaths and losses being uncommon. When the pattern is “the medication works, but stopping it triggers an outbreak,” the problem is often not just bacterial.
The underlying cause is often latent PRRS virus, with secondary mixed infection involving porcine contagious pleuropneumonia.
Antibiotics can only temporarily suppress the bacterial inflammation associated with PRRS; they cannot eliminate the PRRS virus. PRRS continues to damage the lungs and undermine the herd’s immunity, leaving pigs in a subclinical state for a long time. Once the medication wears off, the bacteria rebound alongside the viral damage, and coughing, labored breathing, and deaths occur again.
Check yourself against 3 typical signs:
Coughing and labored breathing improve with medication, but quickly return after treatment stops; the condition never fully resolves despite prolonged treatment;
Scattered deaths continue; daily losses may not seem high, but cumulative losses by month’s end are substantial;
The pigs have pale coats, low energy, reduced feed intake, and slow growth, with recurring low-grade fever.
To distinguish similar diseases: Mycoplasma-associated coughing and breathing difficulties usually cause a dry cough, while feed intake remains largely normal and prolonged deaths are rare; PCV disease is mainly characterized by weight loss and dermatitis, with coughing and breathing difficulties not being core symptoms. When pigs show abdominal breathing, fever and labored breathing, accompanied by sporadic deaths, PRRS coinfection with swine influenza is more likely.
Two other key contributing factors should not be overlooked:
First, poor housing conditions: large day-to-night temperature fluctuations and inadequate ventilation, with excessive ammonia and humidity, continuously damage the respiratory mucosa and allow pathogens to invade repeatedly;
Second, feed mold levels exceed limits. Toxins damage the liver and kidneys and reduce immunity, so even mild stress can make the herd sick, greatly reducing the effectiveness of medication.
To get persistent coughing and wheezing under control, use these two approaches:
Approach one: Control toxins and boost immunity to cut off the basis for secondary infections
Prioritize mixing tylvalosin with astragalus polysaccharides into the feed to suppress the PRRS virus load and boost herd immunity, reducing the risk of secondary respiratory disease. Add a mold binder to feed regularly as part of routine feeding to prevent ongoing mold exposure from depleting the animals’ resistance.
Second approach: targeted bacterial control + environmental improvements
Pair this with a respiratory treatment plan to control secondary infections following contagious pleuropneumonia. At the same time, improve ventilation, manage temperature differences, and inspect feed regularly to prevent mold growth. Only by managing viruses, bacteria, and the environment together can recurrence be reduced.
A friendly reminder: Each pig farm has different pathogen strains and herd health backgrounds, so do not blindly copy a treatment plan and medicate without proper assessment. Where possible, prioritize testing or an on-site veterinary diagnosis before medication is used.
Many pig farms suffer ongoing losses due to recurring coughing and breathing difficulties. The root cause is often treating only the surface symptoms while overlooking viruses lurking in the body. Identifying the underlying cause and putting the treatment plan into practice can effectively reduce sporadic deaths and culls, save on medication costs, and reduce losses.