Combating PRRS by breeding pigs with enhanced, overall robustness to disease

Porcine Reproductive and Respiratory Syndrome (PRRS) is a serious pig disease that causes major economic losses in the pig production sector. Topigs Norsvin has made significant investments to develop pigs that are genetically more robust to PRRS, as well as other diseases.

According to Topigs Norsvin geneticist and researcher Dr. Jenelle Dunkelberger: “Traditional disease control strategies have limited efficacy for combating PRRS. Therefore, alternative disease control strategies, such as genetic selection for enhanced, natural robustness to PRRS challenge, must be considered.” Breeding values for PRRS resistance have been part of Topigs Norsvin’s selection index since 2018. 
This step has already helped to improve host response to PRRS challenge. “Our end goal, however, is not just to improve host response to PRRS, but to any and all pathogens that an animal might encounter throughout its lifetime. We refer to this as overall robustness to disease,” Dunkelberger explains.

Traditional breeding
“In the event of a disease challenge, you may observe pigs that continue to eat and grow as if they are unaffected by the disease, while others die (and responses anywhere in between). Differences in robustness has a genetic basis. Therefore, we don’t need genetic engineering technologies, such as gene-editing, to improve response to disease challenge. Rather, we can simply make use of the existing genetic variation within our populations to breed pigs for improved, natural robustness to disease using traditional breeding strategies.” 
This is the same approach Porcine Reproductive and Respiratory Syndrome (PRRS) is a serious pig disease that causes major economic losses in the pig production sector. Topigs Norsvin has made significant investments to develop pigs that are genetically more robust to PRRS, as well as other diseases. that Topigs Norsvin uses to make genetic improvement in every other trait within the breeding goal. 

Valuable data
Topigs Norsvin collects genotypic and phenotypic information on animals during controlled, multifactorial disease challenge trials. These data are used to develop breeding values for overall robustness to disease. Dunkelberger: “This requires a huge investment from our organization. We collect these data because the genetic basis of performance under conventional health and performance under disease challenge, is not the same. Therefore, we have to collect data on pigs going through a disease challenge to facilitate the development of breeding values for this trait.”
Dunkelberger continues: “These challenge models consist of viral and bacterial pathogens, so that we can breed pigs for better generalized immunity. This is critical - too many pathogens threaten our industry to focus on only one pathogen at a time. Plus, we can’t predict what pathogens might emerge in the future. We are also passionate about this approach because pigs with enhanced, overall robustness to disease require fewer antibiotics. We’ve shown this in our research trials. Therefore, rearing pigs with enhanced, natural robustness to disease is a great solution for producers looking to reduce antibiotic usage as one of their sustainability goals.”