title: Genetic and genomic basis of antibody response to porcine reproductive and respiratory syndrome (PRRS) in gilts and sows.
abstract: Our recent research showed that antibody response to porcine reproductive and respiratory syndrome (PRRS), measured as sample-to-positive (S/P) ratio, is highly heritable and has a high genetic correlation with reproductive performance during a PRRS outbreak. Two major quantitative trait loci (QTL) on Sus scrofa chromosome 7 (SSC7; QTLMHC and QTL130) accounted for ~40 % of the genetic variance for S/P. Objectives of this study were to estimate genetic parameters for PRRS S/P in gilts during acclimation, identify regions associated with S/P, and evaluate the accuracy of genomic prediction of S/P across populations with different prevalences of PRRS and using different single nucleotide polymorphism (SNP) sets.
  
  
  
  Phenotypes and high-density SNP genotypes of female pigs from two datasets were used. The outbreak dataset included 607 animals from one multiplier herd, whereas the gilt acclimation (GA) dataset included data on 2364 replacement gilts from seven breeding companies placed on health-challenged farms. Genomic prediction was evaluated using GA for training and validation, and using GA for training and outbreak for validation. Predictions were based on SNPs across the genome (SNPAll), SNPs in one (SNPMHC and SNP130) or both (SNPSSC7) QTL, or SNPs outside the QTL (SNPRest).
  
  
  
  Heritability of S/P in the GA dataset increased with the proportion of PRRS-positive animals in the herd (from 0.28 to 0.47). Genomic prediction accuracies ranged from low to moderate. Average accuracies were highest when using only the 269 SNPs in both QTL regions (SNPSSC7, with accuracies of 0.39 and 0.31 for outbreak and GA validation datasets, respectively. Average accuracies for SNPALL, SNPMHC, SNP130, and SNPRest were, respectively, 0.26, 0.39, 0.21, and 0.05 for the outbreak, and 0.28, 0.25, 0.22, and 0.12, for the GA validation datasets.
  
  
  
  Moderate genomic prediction accuracies can be obtained for PRRS antibody response using SNPs located within two major QTL on SSC7, while the rest of the genome showed limited predictive ability. Results were obtained using data from multiple genetic sources and farms, which further strengthens these findings. Further research is needed to validate the use of S/P ratio as an indicator trait for reproductive performance during PRRS outbreaks.
authors.affiliation: Department of Animal Science, Iowa State University, Ames, IA, 50011, USA.|Department of Animal Science, North Carolina State University, Raleigh, NC, 27695, USA.
authors.forename: Nick V L
authors.initials: NV
authors.lastname: Serão
authors.affiliation: Genesus Inc., Oakville, MB, R0H 0Y0, Canada.
authors.forename: Robert A
authors.initials: RA
authors.lastname: Kemp
authors.affiliation: Department of Animal Science, University of Nebraska-Lincoln, Lincoln, NE, 68583, USA.
authors.forename: Benny E
authors.initials: BE
authors.lastname: Mote
authors.affiliation: Canadian Centre for Health and Safety in Agriculture, University of Saskatchewan, Saskatoon, SK, S7N 2Z4, Canada.
authors.forename: Philip
authors.initials: P
authors.lastname: Willson
authors.affiliation: Department of Large Animal Clinical Sciences, University of Saskatchewan, Saskatoon, SK, S7N 5B4, Canada.
authors.forename: John C S
authors.initials: JC
authors.lastname: Harding
authors.affiliation: The Roslin Institute and Royal (Dick) School of Veterinary Studies, University of Edinburgh, Easter Bush, Midlothian, EH25 9RG, UK.
authors.forename: Stephen C
authors.initials: SC
authors.lastname: Bishop
authors.affiliation: Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, AB, T6G 2R3, Canada.
authors.forename: Graham S
authors.initials: GS
authors.lastname: Plastow
authors.affiliation: Department of Animal Science, Iowa State University, Ames, IA, 50011, USA. jdekkers@iastate.edu.
authors.forename: Jack C M
authors.initials: JC
authors.lastname: Dekkers
mesh_terms: D000818:Animals; D000914:Antibodies, Viral / Q000097:blood; D000917:Antibody Formation / Q000235:genetics*; D001947:Breeding; D005260:Female; D055106:Genome-Wide Association Study; D023281:Genomics / Q000379:methods*; D005838:Genotype; D010641:Phenotype; D020641:Polymorphism, Single Nucleotide; D019318:Porcine Reproductive and Respiratory Syndrome / Q000235:genetics* / Q000276:immunology*; D040641:Quantitative Trait Loci; D034421:Sus scrofa / Q000235:genetics* / Q000821:virology; D013552:Swine
chemical_list: D000914:Antibodies, Viral
keywords: Disease resilience; Disease resistance; Genomic prediction; Genomic selection; PRRSV; Vaccination