By Adam Schelkopf, DVM
As the seasons change, thoughts of Porcine Respiratory and Reproductive Syndrome (PRRS) virus plague many producers. Not only does this virus cause significant health and financial challenges to the swine industry, but it has a reputation for infecting swine herds more frequently during the fall/winter/spring.
For Pipestone System, and the industry as a whole, we have become better every year as we look at the rate of new infections in Pipestone System sow farms, as well as infections across a large number of herds in the U.S. monitored through the late Dr. Bob Morrison’s Swine Health Monitoring Project. This proves that the research generated and efforts put forth towards combating this disease are driving progress.
As we look in the PRRS control toolbox, one tool that has proven effective for aiding our control efforts is the modified live PRRS vaccine. Modified live PRRS vaccine has two primary benefits and warrants strong consideration for your operation.
1. Growing pig performance.
In a controlled research study in which pigs were challenged with a virulent strain of PRRS virus, pigs that were previously vaccinated with PRRS vaccine significantly outperformed the pigs that were not vaccinated with PRRS vaccine in wean-to-market average daily gain. They also had less pigs that needed to be sold as culls at the end of the group. This economic return for vaccination was $4.35 in this study over non-vaccinated pigs.
2. Controlling viral spread in a neighborhood.
PRRS virus has been shown to travel via aerosol spread, and often can infect multiple sites in a geographical region when present. One way to help reduce the number of herds that become infected is to reduce the time and degree to which this virus is shed from infected populations. This strategy is used in pig-dense areas and areas in which sows are present to decrease viral density in an area. In another controlled trial, it was demonstrated that when challenged with a virulent field strain of PRRS, pigs that were vaccinated with a modified live PRRS vaccine shed significantly less virus from the infected facility.
Air samples were collected daily from this facility after pigs were challenged and only 5 days with positive air samples were detected outside of the room with vaccinated pigs, compared to 27 days with positive air samples in the non-vaccinated pigs. Additionally, PRRS virus was only detected in the air out to day 6 post-challenge in the vaccinated group, compared to day 55 in the non-vaccinated group. This shows that PRRS vaccine is a beneficial tool to help reduce the amount of virus that is shed from infected barns and reduce the challenge to nearby barns, helping protect your neighborhood.
Evaluate your strategies going into historical “PRRS season.” All of the tools in the PRRS control toolbox, including good biosecurity practices, air filtration, and regional and herd control strategies are all important. PRRS vaccine is just another tool that helps us in our efforts to combat this disease.
Modified live PRRS vaccine improves the health and performance of the growing pig and controls viral presence within regions. Additionally, in an era where pressure is applied on antimicrobial use in livestock operations, we must constantly evaluate our production practices and health control strategies. PRRS virus infections warrant the need for antimicrobial use within infected populations and is one more reason to put forth our best efforts to prevent infection or control disease. We must use all the tools in our toolbox to help control this disease and PRRS vaccines can help.
Adam Schelkopf, DVM, has been with Pipestone Veterinary Services since 2012 focusing on swine medicine and production. He received his DVM from the University of Illinois in 2012.
More from Farm Journal's PORK: