This is our Friday rubric: every week a new Science Page from the Bob Morrison’s Swine Health Monitoring Project. The previous editions of the science page are available on our website.
University of Minnesota researchers Mariana Kikuti, Miranda Medrano, Marcello Melini, Carles Vilalta, Juan Sanhueza, Emily Geary, Cesar Corzo compare PRRSV disease status between systems that originally shared their sow herd status with MSHMP and those that joined the program later.
- PRRS prevalence dynamics among cohorts remain relatively comparable.
- Systems that joined the program later seem to have a higher prevalence of status 2fvi farms, particularly in the most recent years.
The Morrison Swine Health Monitoring Project (MSHMP) originally started with 13 production systems who voluntarily shared their sow herd PRRSV disease status on a weekly basis. As the program continued to expand, the number of sow herds located in different regions provided a better perspective of disease occurrence dynamics.
A comparison from a prevalence standpoint between the cohort of farms belonging to the original 13 systems at the start (CS) of the MSHMP and the cohort of farms from systems that joined the program later (CL) was performed with the objective of assessing whether the patterns between cohorts compare. Although the historical prevalence of PRRS statuses according to the AASV categories are relatively comparable (Figure 1), there was a clear shift towards more use of MLV over LVI in both the CS/CL cohorts.
In contrast, although the CL cohort also adopted MLV, several sites continued to use LVI. Currently (in March 30, 2022), the proportion of farms using LVI in the CS versus the CL cohort is 3.7% and 8.9%, respectively (Table 1).
The continuous addition of systems from multiple different regions to the program aims at increasing its representativeness and robustness to monitor swine diseases of importance to the U.S. industry.