For both humans and animals the transition period from fall to winter can raise some health issues as buildings are closed up and ventilation, heating and air-quality systems are tested. For pigs, this means that porcine respiratory disease complex (PRDC) can become more of a challenge.
As identified by its name, PRDC is driven by more than one pathogen or disease. Mary Battrell, DVM, with Murphy-Brown points out that some of the more common viral components of PRDC include porcine reproductive and respiratory syndrome virus (PRRS), swine influenza virus (SIV), porcine cirovirus type 2 (PCV2), and porcine respiratory corona virus (PRCV). Certainly, PRRS, SIV, PCV2 are major players in the complex.
But, she points out that bacterial infections also can play a role, including Mycoplasma hyopneumoniae, Pasteurella multocida, Streptococcus suis, Haemophilus parasuis, Actinobacillus pleuropneumoniae, Actinobacillus suis, and Salmonella choleraesuis. Bacterial infections alone are not that difficult to treat or even prevent, Battrell says, but when the pig faces a combination of pathogens and/or stressors PRDC can surface and cause problems.
Clinical signs of PRDC in grow/finish pigs may include: coughing, sneezing, nasal discharge, tear stains under the eyes, lethargic pigs that often go off feed, pigs with elevated rectal temperatures, and labored breathing.
So, what can you do to protect your herd and keep pigs on a healthy path? Battrell offers these six steps:
- Identify the pathogens or diseases that may be involved in your herd. This requires compiling and monitoring a combination of herd history, clinical signs and laboratory diagnostics. She advises consulting with your veterinarian or the diagnostic laboratory that will be receiving any samples to insure that you: select the right pigs, collect the correct samples, preserve and submit samples so that you can maximize the results.
- Consider how the disease or pathogens in question are transmitted. Are there biosecurity measures that can reduce the pathogen or disease spread? Review the protocols that you have in place. Stressors such as high stocking densities, humidity, poor air quality, poor sanitation and excessive fluctuations in environmental temperatures will add to the pathogen load that the pigs face.
- Develop an action plan. There are several things to consider in this process, Battrell points out. For example, before implementing a vaccination program, you need to determine the level of maternal antibody and when levels might decline enough to allow for the vaccine to be effective. Also, what is the pigs’ PRRS status? What is the timing of infection? Do pigs have sufficient time to respond to the vaccine before being challenged? What is the immunity duration? Will one or two doses of the vaccine protect pigs all the way to market? Are preventative antibiotics given at the time of disease transmission a better alternative
- Implement your plan and measure the results. “This sounds easy, but in fact can be quite difficult to accomplish,” Battrell notes. Statistical analysis and multiple replications will be necessary to determine true response and results of your efforts
- Monitor results—this means charting performance trends and statistical process control. “These are useful tools for monitoring change over time,” Battrell adds.
- Disease status within a herd will change, so you will need to constantly reevaluate processes and options, she concludes.