Improving PRRS Control: A Scientific Look at Two Strategies

October 15, 2014 — 

Porcine Reproductive and Respiratory Syndrome (PRRS) continues to be a significant profit robber in U.S. swine herds, with an estimated annual cost of more than $600 million. The first part of a three-part webinar at PorkNetwork.com focuses on how producers can improve PRRS control in the breeding herd, in growing pigs, and in the entire system. [Source: Pork Network, 10/13/2014 by JoAnn Alumbaug]

The three webinar segments can be watched separately or the complete webinar can be viewed in its entirety.

Segment One: Live Virus or Modified-Live Vaccine?

The first segment features Montse Torremorell, DVM, PhD. She discusses breeding herd stabilization for PRRS, comparing live virus (LV) and modified-live vaccine (MLV) in a “load-close-expose” protocol. The findings are based on Dr. Daniel Linhares’ research study. Dr. Torremorell is an associate professor and is the Allen D. Leman Chair, Swine Health and Productivity in the College of Veterinary Medicine at the University of Minnesota (UM).

The researchers wanted to determine which of those strategies (using LV or MLV) would be more cost-effective for producers, and help them achieve PRRS-negative pigs faster in the nursery (called “time to negative pig,” or TTNP, which requires at least three months of negative tests).

Immunity Matters

Herds that had been previously exposed to PRRSv returned to negative status more quickly than herds in which the animals had not been exposed to the virus. Another take-home point from the study was that the live virus was much harder on the farm’s production compared to farms where the modified live virus vaccine was used. “We found the herds that used vaccine were able to reach baseline production sooner than those herds that had used live virus inoculation. That was one of the key differences between the two strategies,” says Dr. Torremorell. Significant Difference

The difference was almost 1,500 pigs per 1,000 sows. If you do the math, with 3,000 and 5,000 sows, the number of pigs saved by using vaccine rather than the live virus was roughly double.

The study is a major accomplishment, with significant and relevant findings for producers. Dr. Linhares study was funded through a Boehringer Ingelheim Vetmedica PRRS Research Award. Click here to watch the first segment of the webinar.