Should we redirect our research efforts to focus on PRRS prevention and control in growing and finishing pigs? This was the call for action made by Dr. Montse Torremorell, Associate Professor at the University of Minnesota when she opened the special session “Grow/finish phase of production: What are we learning and implications for making progress on PRRS control.” sponsored by Boehringer Ingelheim during the North American PRRS Symposium this past weekend in Chicago. Torremorell argued that if the swine industry wants to advance regional PRRS control, more emphasis needs to put on preventing and controlling PRRS in growing pigs.
Thanks to the Morrison Swine Health Monitoring Program, there is reliable information regarding the PRRS status of sow herds in the US. Most of the recorded herds are either stable thanks to vaccination programs or negative at weaning. What about those pigs after they leave the sow farm? “We really don’t have a good picture of what happens in the US in those grow-finish pigs.” Torremorell argued.
Dr. Jose Angulo, Master student at the University of Minnesota and PRRS Technical Manager for Zoetis, provided some insights into this question. Angulo described the dynamics of PRRSV infections in growing pigs with approximately 50% of the wean-to-finish sites in the study having evidence of wild type PRRS infection. His data also showed that sites with wild type PRRS virus had higher mortality than the ones without.
“I think there is evidence that suggests that from a control point of view, if we really want to make an effort and advancement in PRRS control in the region, we have to look into the growing pigs.”
Dr. Montse Torremorell
Mariana Kikuti from the University of Minnesota presented insightful information on genetic sequencing of PRRSV in growing pigs and provided insights on the expected sequence variation observed in the sites even when a single virus is found circulating. Cesar Moura a PhD student at Iowa State University in Dr. Daniel Linhares’ group presented the economic benefits of using two doses of a modified live vaccine when these are given in unstable herds. The results were very encouraging and offered alternatives for PRRSV control. Lastly, Edison Magalhaes, also a graduate student at ISU presented on drivers of wean-to-finish mortality and the impact on disease status and showed the benefit of linking different production databases to predict the performance of pigs.
Overall, this special session on the control of PRRS in the field was inspirational, relevant and brought the message home that we can’t give up on our fight against PRRSV and that we need to focus our efforts on the growing pigs without lowering the bar in the efforts already in place in the breeding herds.