Editor’s note: Information in this article was obtained from a copyrighted article published in the American Veterinary Medical Association’s, (AVMA) journal, JAVMA, Vol 227 No. 3, August 1, 2005, beginning on page 385. AVMA has granted Swine Practitioner magazine permission to use information from the JAVMA article.

How much is PRRS costing United States pork producers?

A recent study estimates the cost to be in excess of $560 million in losses each year. Results of the study were reported last summer in JAVMA, the refereed journal of the American Veterinary Medical Association, in the article, “Assessment of the economic impact of porcine reproductive and respiratory syndrome on swine production in the United States.”

Authors of the article included Eric J. Neumann, DVM, MS, National Pork Board; James B. Kliebenstein, PhD, Department of Economics, Iowa State University (ISU); Colin D. Johnson, MS, Department of Animal Science, ISU; John W. Mabry, PhD, Department of Animal Science, ISU; Eric J. Bush, DVM, MS, USDA, Centers for National Animal Health Surveillance (NAHS); Ann H. Seitzinger, PHD, NAHS; Alice L. Green, DVM, MS, NAHS; and Jeffrey J. Zimmerman, DVM, PhD, DACVPM, Department of Veterinary and Production Animal Medicine, ISU.

The study was funded in part by the National Pork Board. Although previous research has attempted to estimate the cost of PRRS, “in my opinion this is the first in‑depth study on the economics of PRRS.” says Zimmerman. “That is not to say that the previous studies were inadequate, it is just that most of them were based on a small sampling.”

 

In the grow-finish production phase, the increased cost of PRRS was estimated at $7.67 per pig, due to increased mortality, decreased feed efficiency (higher feed costs) and reduced ADG. The total cost of PRRS in the grow-finish phase was estimated at $292.23 million.

“The objective of the study reported here was to estimate the annual cost of PRRS to U.S. swine producers,” says the JAVMA article. “The cost analysis was structured to estimate the economic impact of an outbreak of PRRS in three distinct production phases: breeding (breeding through weaning), nursery (weaning through approximately 11 weeks of age), and finishing (approximately 11 through 26 weeks of age). The analysis targeted the costs of farm‑level production losses attributable to PRRS and did not include costs associated with preventing the introduction of PRRS virus into herds and monitoring endemically infected herds or attributable to subclinical infection with PRRS virus (i.e., health effects of infection despite a complete lack of clinical disease).”

Data source
According to the JAVMA article, data for the economic analyses were obtained from a case study of 10 farms that had clinical signs of PRRS. Also, because porcine reproductive and respiratory syndrome was a specific focus of a USDA National Animal Health Monitoring System (NAHMS) survey on swine in 2000, data available from the NAHMS survey were also used in the economic study to estimate the incidence of PRRS in the U.S. swine herd.

The 10 producers from the case study farms represented a range of production types and sizes. These producers included independent producers and those that were part of a vertically integrated system.

Production types included farrow‑to‑market, weaned pig (nursery) and market pig (grow‑finish) operations. Breeding operations ranged from 320 to 10,200 sows. Nursery and finisher operations included groups of 300 to more than 1,000 pigs per group.

 

The economic impact of PRRS in the nursery phase of U.S. pig production was estimated at $6.0l per pig.

According to the JAVMA article, producers and herd veterinarians provided information on the PRRS virus status of the farms, plus detailed data on productivity. Farms with uncertain classification for the PRRS virus status before an outbreak or with multiple secondary diseases that impacted production were excluded from the study.

For the study’s purposes, PRRS‑affected breeding herds were identified on the basis of detection of clinical signs compatible with PRRS in combination with laboratory confirmation of PRRS virus in affected pigs, the JAVMA article points out. “Within herds, these criteria (i.e., clinical signs and laboratory confirmation) were used to define the initiation of an outbreak. In breeding operations, clinical signs included a decrease in farrowing rate, an increase in abortion rate and an increase in mortality rate of pre-weaning pigs. An outbreak of PRRS was considered terminated when values for production variables returned to within ± 5% of historical values for that operation and the herd veterinarian determined that clinical expression of the disease no longer impacted productivity.

“Values for production variables were compared between PRRS‑unaffected (i.e., conditions before an outbreak) and PRRS‑affected (i.e., conditions during or after an outbreak) farms by comparing production efficiencies. The economic impact of PRRS was calculated by multiplying the magnitude of PRRS‑induced production deficiencies by standard cost‑of‑production indices calculated from annual estimates of costs for midwestern U.S. swine producers.”

The JAVMA article says that in nursery and grow‑finish pig populations, affected groups of pigs were identified on the basis of clinical signs compatible with PRRS, results of diagnostic tests, and the clinical judgment of the herd veterinarian.           

Economic impact
According to the JAVMA article, total cost of an outbreak of PRRS for the breeding‑farrowing phase of production was estimated to be $74.16 per litter due to reduced farrowing rates and a decrease in the number of pigs weaned per litter. The total cost of PRRS for the breeding-farrowing phase of production was estimated at $66.75 million.

 

The total cost of PRRS on the breeding-farrowing phase of U.S. production was estimated at $66.75 million.

The economic impact of PRRS in the nursery phase of pig production was estimated at $6.0l per pig. These losses resulted from higher mortality, reduced feed efficiency and a reduction in average daily gain (ADG) for PRRS-affected groups. The total cost impact of PRRS in the nursery phase was
estimated at $201.34 million.

In the grow‑finish production phase, according to the JAVMA article, the increased cost of PRRS was estimated at $7.67 per pig, due to increased mortality, decreased feed efficiency (higher feed costs) and reduced ADG. The total cost of PRRS in the grow-finish phase of production was estimated at $292.23 million.

PRRS losses from these three production phases total $560.32 million, the JAVMA article points out.

The JAVMA article says that strengths of the study “were that operations selected for inclusion in the study represented a cross‑section of production styles and scale. Regardless of herd size, the extensive use of computerized health and productivity records by swine producers meant that the quality and quantity of data available for this study were unprecedented for studies on the cost of a disease. Overall, records provided by the 10 case‑study herds included data from 19,875 sows, 939,961 nursery pigs and 970,107 grower‑finisher pigs.”

On the other hand, a limitation of the study, says the JAVMA  article, was that “only a relatively small number of operations provided records. We believe this limitation was offset by the quality of data and the number of swine on which the data were based. Herds with multiple secondary diseases impacting production were excluded from the study.

“Co-infection with bacteria and other viruses can exacerbate PRRS‑associated disease, but these data are difficult to accurately collect, and costs are difficult to apportion among multiple infectious agents. Costs associated with various PRRS‑specific management responses were not included (e.g., purchase and administration of PRRS vaccines, changing suppliers of replacement stock, use of PRRS‑negative semen, modifying facilities or equipment in an effort to prevent or control PRRS, implementing programs to monitor status of herds with regard to PRRS virus, or other similar strategies).

“Costs not incurred by most swine producers were also not included in this analysis (e.g., loss of markets for seedstock herds or boar studs after an outbreak of PRRS at their facility). The analysis did not include possible positive effects on prices of market hogs that would be attributable to the fact that fewer slaughter swine were produced as a result of PRRS-related deaths. Overall, the costs derived through the approach we used represented relatively conservative estimates of the effect of PRRS.”

Abstract of JAVMA article

Following is the abstract of the recent JAVMA article reporting on an in-depth study of the economic costs of porcine reproductive and respiratory syndrome (PRRS) to the United States swine industry. It is reprinted by permission from the American Veterinary Medical Association.

  • Objective: To estimate the annual cost of infections attributable to PRRS virus to U.S. swine producers.
  • Design: Economic analysis.
  • Sample population: Data on the health and productivity of PRRS‑affected and PRRS‑unaffected breeding herds and growing‑pig populations were collected from a convenience sample of swine farms in the midwestern United States.
  • Procedure: Health and productivity variables of PRRS‑affected and PRRS‑unaffected swine farms were analyzed to estimate the impact of PRRS on specific farms. National estimates of PRRS incidence were then used to determine the annual economic impact of PRRS on U.S. swine producers.
  • Results: PRRS affected breeding herds and growing pig populations as measured by a decrease in reproductive health, an increase in deaths and reductions in the rate and efficiency of growth. Total annual economic impact of these effects on U.S. swine producers was estimated at $66.75 million in breeding herds and $493.57 million in growing‑pig populations.
  • Conclusions and clinical relevance: PRRS imposes a substantial financial burden on U.S. swine producers and causes approximately $560.32 million in losses each year. By comparison, prior to eradication, annual losses attributable to classical swine fever (hog cholera) and pseudorabies were estimated at $364.09 million and $36.27 million, respectively (adjusted on the basis of   year 2004 dollars). Current PRRS control strategies are not predictably successful; thus, PRRS‑associated losses will continue into the future. Research to improve our understanding of ecologic and epidemiologic characteristics of the PRRS virus and technologic advances (vaccines and diagnostic tests) to prevent clinical effects are warranted. (J Am Vet Med Assoc 2005;227:385‑392)

How PRRS compares with the cost of major swine diseases of the past

How does the economic cost of PRRS compare with costs of major swine disease problems of the past?

A study reported in the American Veterinary Medical Association journal, JAVMA, compared the economic costs of PRRS with the costs of classical swine fever (hog cholera) and pseudorabies.

“In 1961, it was estimated that classical swine fever (hog cholera) cost U.S. producers $57.4 million annually ($15.4 million in disease costs and $42 million for the purchase and administration of vaccines),” the JAVMA article states. “Adjusted for inflation by use of the consumer price index, this is equivalent to $364.09 million in year 2004 dollars.”

Regarding the cost of pseudorabies, the JAVMA article says, “In 1987, it was estimated that the annual cost of pseudorabies (Aujeszky disease) was $21.25 million, including $9.05 million in losses attributable to clinical disease, $1.89 million for serologic tests and $10.31 million for the purchase and administration of vaccines. Adjusted for inflation, this is equivalent to $36.27 million in year 2004 dollars.

“Classical swine fever and pseudorabies were targeted for eradication from the United States on the basis of excessive ongoing losses to swine producers caused by these diseases. The eradication program for classical swine fever began in the United States in the summer of 1962 and was officially completed on January 1, 1978. The eradication program for pseudorabies officially began on January 1, 1989, and the National Pseudorabies Control Board declared that all commercial swine herds in the United States were free of pseudorabies in the fall of 2004.

“Since its emergence as a clinical entity in the late 1980s, PRRS has proven to be a persistent and insidious threat to the health and productivity of the U.S. swine herd. Among those responsible for swine health, it is not surprising that the annual cost of PRRS to US swine producers greatly exceeds the costs of pseudorabies and classical swine fever, the historical nemesis of swine producers.”