As pork production has evolved, the industry has utilized technical and scientific advancements to successfully control and eradicate disease. However, even with these advances, producers and veterinarians are continuously challenged. One disease that seems to have evolved with modern swine production is respiratory disease.
Porcine Respiratory Disease Complex (PRDC) is still prevalent in U.S. swine herds, even with the advent of improved management technologies, advanced biologics, and a better understanding of the complex relationship between respiratory pathogens, their host and the environment. Chronic respiratory disease is considered one of the primary factors contributing to economic losses. In fact, “The estimated cost (depending on co-factors) is well over $600 million to the industry,”Dr. Brian Payne, swine technical manager for Boehringer Ingelheim Vetmedica, Inc.
“Porcine Respiratory Disease Complex presents a substantial challenge to both veterinarians and producers,” points out Dr. Cary Honnold, DVM, Purdue University. “In order to combat this problem and maintain control of it, strict management policies and environmental monitoring will have to be consistently maintained.”
The causes of PRDC are multifaceted and vary from farm to farm.
“Improved diagnostic tools (i.e. immunohistochemistry and polymerase chain reaction or PCR) have increased the speed and accuracy of finding out exactly what agents are involved in each respiratory disease outbreak,” says Dr. Pat Halbur with the College of Veterinary Medicine at Iowa State University.
“Once the pathogens involved are confirmed and prioritized, progressive veterinarians and producers quickly move towards minimizing losses and driving the disease subclinical or eliminating it from the production system with appropriate medication, vaccination, and production changes,” adds Dr. Halbur.
In some cases this may involve the sow herd, or it may involve pig flow changes, weaning age changes, ventilation modifications, pulse medication, and/or vaccination. Cross sectional necropsies and serological profiles allow for defining where in the production system to implement vaccination and medication.
Fortunately, quality vaccines are available for the most important primary viral (PRRSV, SIV, PRV) and mycoplasmal pathogens which initiate and/or play a major role in most of the severe respiratory disease outbreaks, notes Dr. Halbur. He says, “For the long term, management strategies focused on sow herd stabilization and segregated early weaning (SEW) using multiple site production seem most appropriate. SEW is an established way to attain high health status pigs. We likely will rely on strategically administered high quality vaccines to establish uniform immunity and lessen the risk of respiratory disease outbreaks in these highly susceptible populations of pigs.”
Dr. Honnold agrees. He says, “Implementing strategic vaccination programs directed at stabilizing and developing a uniform immune status within the sow herd to eliminate subpopulations is crucial. Consistent vaccination schedules, along with all in/ all out facilities, strict biosecurity, segregated early weaning, and the use of multisite production, should aid in the prevention and severity of PRDC.”