Abstract
BackgroundRespiratory diseases are among the most important factors affecting swine farm productivity in Canada. The objectives of this study were to investigate antibody responses to porcine reproductive and respiratory syndrome virus (PRRSV), influenza A virus (IAV), and Mycoplasma hyopneumoniae (M. hyopneumoniae) from weaning to the end of the finisher stage on a subset of commercial swine farms in Ontario, Canada, and to examine the association between nursery diet and antibody responses.ResultsOverall, older pigs were more likely to test seropositive for PRRSV and less likely to test seropositive for M. hyopneumoniae (p < 0.001). Pigs were more likely to test seropositive for IAV at weaning and the end of the grower and finisher stages compared to the end of nursery (p < 0.001). Pigs that were seropositive for IAV were more likely to test seropositive for both PRRSV and M. hyopneumoniae (p < 0.001). Two, 9, and 4 groups that had more than 20% of pigs seropositive to PRRSV, IAV, and M. hyopneumoniae, respectively, from the end of nursery to the end of finisher were classified as seropositive. Pigs fed a plant-based (low complexity) diet during nursery were more likely to be seropositive for PRRSV (p < 0.001) but there were no significant differences in seropositivity to IAV or M. hyopneumoniae due to nursery diet complexity.ConclusionsThis study provides information regarding changes in serum antibody in pigs across different stages of production and highlights periods of vulnerability. Additionally, these findings may encourage further research into the effects of nursery diet complexity on disease susceptibility and immune response.
Highlights
Respiratory diseases are among the most important factors affecting swine farm productivity in Canada
Seropositivity to porcine reproductive and respiratory syndrome virus (PRRSV), influenza A virus (IAV), and M. hyopneumoniae at the pig and group level Of the 336 pigs tested for all three pathogens at four visits, 24 (7.1%) were seronegative for all three pathogens throughout production, 165 (49.1%) were seropositive for one at least once over the course of production, 124 (36.9%) were seropositive for two, and 23 (6.9%) were seropositive for all three pathogens
Due to the possible confounding effects of passive immunity on the objectives of this study, groups were considered positive for each pathogen if more than 20% of pigs in that group tested seropositive for that pathogen at least once from the end of nursery to the end of the finisher stage
Summary
Respiratory diseases are among the most important factors affecting swine farm productivity in Canada. Despite efforts to eradicate these pathogens and their associated diseases, they continue to be widespread in the world swine population and result in huge economic losses for pork producers. These infectious agents can be detrimental to production on their own, and the presence of multiple infectious agents on-farm can increase the risk for coinfection [4,5,6,7] and can lead to more severe disease than single infection with either agent(s) [8, 9]. These interactions may further exacerbate declines in producer profits and animal welfare [1]
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