Robert B. Morrison University of Minnesota

Publish Date: April 9, 2012

For certain animal diseases, regional elimination of the pathogen has been the only effective way to control the disease. Regional elimination programs have been reported for diseases such as foot and mouth disease (FMD) where mass vaccination and movement restrictions have proven to be effective.

Publish Date: April 13, 2012

Porcine reproductive and respiratory syndrome emerged as a new syndrome in the US swine population more than two decades ago (Keffaber, 1989). After its initial description, the disease was identified rather quickly in many countries throughout the world. In 1992 the virus was isolated in the US and also in 1992 the consensus decision at the International Symposium on Swine Infertility and Respiratory Syndrome (SIRS) held in St. Paul, MN was made to refer to the syndrome as Porcine Reproductive and Respiratory Syndrome (PRRS) and the virus as PRRS virus (PRRSv). PRRSv has been documented to mutate constantly by changing its genetic appearance (Murtaugh et al. 1995) which presents an important challenge for herd level and regional control.

Publish Date: June 3, 2006

The way that sows are housed during gestation and lactation has moved towards more intensive systems so that sows can be more easily managed and production maximized. At a minimum, some of these factors have contributed to a decline in the productive life of sows in commercial pork production systems. A sow remaining in the breeding herd for fewer parities is likely to produce fewer pigs in her lifetime, compared to a sow that remains in the breeding herd for a longer period of time. This reduces the opportunity of a sow to be sufficiently productive (pigs weaned and sold per lifetime) to achieve a return on the replacement gilt investment cost.