The Fundamentals of Swine Respiratory Disease You Should Know

by Caitlyn Andrews October 27, 2016

Fundamentals of Swine Respiratory Diseases

As temperatures drop this fall, swine producers need to be prepared for diseases that can accompany cooler weather. Swine respiratory disease (SRD) is the leading cause of swine mortality in the United States! Learn how to identify the symptoms, prevent, and treat swine respiratory disease before it becomes a problem in your operation.

What is Swine Respiratory Disease (SRD)?

Swine respiratory disease (SRD) is a leading cause of nursery pigs, grower and finisher deaths in the United States.

SRD can be caused by multiple infectious agents. This can cause varying severity and disease duration.

Primary pathogens of SRD include:

  1. Mycoplasma hyopneumoniae
  2. Actinobacillus pleuropneumoniae (APP)
  3. Bordetella bronchiseptica

Viral agents:

  1. Porcine reproductive and respiratory syndrome (PRRS) virus
  2. Swine influenza virus (SIV)

Common secondary invaders:

  1. Streptococcus suis
  2. Pasteurella multocida
  3. Haemophilus parasuis
  4. Salmonella choleraesuis
  5. Actinobacillus suis

What does this mean for producers? This means that a mix of pathogens, viruses and secondary infectious agents can work together to give your pigs Swine Respiratory Disease. Producers should take preventative measures to protect their swine from diseases.

Symptoms of Swine Respiratory Disease

Symptoms of SRD vary with the pathogens present.

Mycoplasmal (Enzootic) Pneumonia
  • Dry hacking
  • Reduced appetite
  • Note: Difficult to detect because not all pigs will cough or be sick at once.
    Actinobacillus pleuropneumoniae (APP)
    • High temperatures (up to 107 °F)
    • Few, if any, respiratory signs
    • Sudden death
    • Near the end, pigs may show severe breathing difficulties, foamy blood tinged discharge from the mouth and nose, and bluish skin from lack of oxygen in the blood.
    • Note: Very severe and contagious.
      Bordetella bronchiseptica and Pasteurella multocida
      • Chronic, occasional coughing
      • Labored breathing
      • Decreased growth rate
      • Note: These are typically secondary invaders. Swine will usually show symptoms of the primary invader as well as the symptoms listed above.
        Porcine Reproductive and Respiratory Syndrome (PRRS)
        • Fever
        • Reduced appetite
        • Increased respiratory rate
        • Increased mortality rates
        • Note: Coughing is not typical, but this virus leaves swine highly susceptible to other viral and bacterial pathogens.
          Swine Influenza Virus (SIV)
          • Harsh, barking cough
          • Flu-like symptoms
          • Loss of appetite
          • Lethargy
          • Pigs may huddle together
          • High temperatures (up to 107 °F)
          • Labored breathing
          • “Thumping” - rapid, shallow abdominal breathing
          • Note: Pigs with SIV will usually show symptoms within 12 – 24 hours of being infected.
            Streptococcus suis
            • Increased mortality rates
            • Typical respiratory symptoms
            • Weight loss
            • Note: Often a secondary contributor to swine pneumonia.
            Haemophilus parasuis
            • Causes Glässer’s Disease: fibrinous polyserositis, arthritis, meningitis
            • Rough hair coat
            • Fever
            • Loss of appetite
            • Listlessness
            • Difficulty breathing
            • Swollen joints
            • Lameness
            • Tremors
            • Squealing
            • Lack of coordination
            • Cyanosis
            • Sudden death

              Swine Respiratory Disease Prevention and Contributing Factors

              Here are a few of the factors that contribute to swine respiratory disease:

              • Poor ventilation and humidity
              • Overcrowding and large group sizes
              • Variable temperatures and wind speeds
              • High levels of ammonia or carbon dioxide
              • Incoming pigs
              • Movement of carrier pigs
              • Poor nutrition and dietary changes
              • Stress
              • High dust levels

                Here are some preventative measures you can take to reduce the risk of your pigs contracting swine respiratory disease:

                1. Control environmental factors mentioned above that contribute to diseases, such as overcrowding, nutrition and ammonia levels.
                2. Avoid purchasing pigs, especially finisher pigs, from multiple sources if possible.
                3. Use preventative vaccines and medicated feeds to help prevent respiratory diseases. Consult with your vet to determine the best preventative measures to take for your operation.
                4. Isolate pigs showing symptoms of disease in sick pens whenever possible.
                5. If swine respiratory disease is already on your farm, consult with your vet to identify the agents and causes involved. A proper diagnosis will allow you to determine the most effective course of treatment and help you prevent the disease from spreading.

                Swine Respiratory Disease Treatments

                It’s important to note that you cannot diagnose the pathogens present by simply looking at a sick pig. You should consult with your veterinarian for a proper diagnosis to determine the treatment necessary.

                The same preventative measures above, such as making sure your facility has proper ventilation, apply to treatment as well. Keep a clean operation, minimize stress and movement of incoming pigs, and keep sick swine isolated from healthy pigs. There are several over the counter medications that will help you combat respiratory disease in swine, including:

                Injectable solutions:

                • Agrimycin 200*
                • LincoMed 300*

                Water solubles:

                • Agrimycin 343*
                • SMZ-Med 454*
                • Tetra-Bac 324*

                *This product switched to Rx only status on Jan 1, 2017.

                Be sure to involve your vet at the first signs of respiratory diseases, especially in large operations, to keep the disease from becoming a widespread issue among your facility. Your veterinarian can prescribe prescription medications when necessary.

                In conclusion, your best course of action to is to take preventative measures to keep your swine from catching respiratory illnesses. Respond quickly when symptoms arise so you can begin treatment as soon as possible.


                The Pig Site: Respiratory Diseases and Control Strategies

                Zoetis: Swine Respiratory Disease

                Caitlyn Andrews
                Caitlyn Andrews


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