Posted by Dr. Steve Dudley on June 16 2004 09:27
Swine Newsletter 4th Quarter 2004
Respiratory disease is a common cause for increased morbidity and mortality in nursery and grow/finish operations. It leads to decreased rate of gain and feed conversion. Signs of respiratory disease include coughing, lethargy, runny eyes, off feed, nasal discharge, fevers, and difficulty breathing.
Viruses involved in causing respiratory disease include PRRS, SIV, and Circovirus. Bacteria involved include Mycoplasma, Haemophilus parasuis, Pasteurella multocida, Actinobacillus suis, Streptococcus suis, and Salmonella choleraesuis.
Most bacterial infections can be prevented when they occur alone, but bacterial and viral causes for respiratory disease often occur together. A virus will invade the lungs and decrease the natural ability for the lungs to fight infection. This allows bacteria to come in more easily and cause a secondary bacterial infection.
Although bacteria and viruses are the primary cause of respiratory disease, environmental changes can also decrease the pig's ability to fight infections. Proper ventilation will assist in decreasing drafts, regulating temperature, controlling moisture, and ammonia. Transporting and mixing increases the stress on the pigs and can also decrease immunity to allow disease agents to take over in the lungs
When respiratory problems are the problem on the farm, it is important to develop a plan for treatment and prevention. Identification of the disease agent is ideal for treatment. A herd walk through to evaluate clinical signs, necropsy, and diagnostics will assist in identifying the virus or bacteria causing the pneumonia. This information will assist in determining the best treatment for the infected pigs.
Prevention is also important to control pneumonia. Strategic vaccination can assist in prevention of respiratory disease. Vaccination is commonly performed for flu and Mycoplasma pneumonia. It is ideal to develop a vaccination protocol to provide protection prior to disease problems within a herd. Other prevention measures include all-in-all-out flow, clean boots and coveralls for visitors, using recommended stocking densities, and maintaining good air quality and sanitation.
If respiratory disease is a problem in your herd, identifying the causative organism will assist in making a treatment plan. This will also help in developing a strategic vaccination protocol and prevention plan for future groups and will assist in producing a higher quality pig.