title: A 5-year study of the incidence and economic impact of variant infectious bursal disease viruses on broiler production in Saskatchewan, Canada.
abstract: While the prevalence of infectious bursal disease virus (IBDV) on chicken farms in some provinces of Canada has been documented, the economic impact of variant IBDV infection on the broiler chicken industry in Saskatchewan has not. The objectives of this study were to identify the variant strains of IBDV circulating on Saskatchewan chicken farms and evaluate their economic impact on broiler production. Infection due to IBDV was detected in 43% of Saskatchewan chicken farms, with variant strains detected in infected birds closely related predominantly to NC171, 586, and Delaware-E. Infected flocks showed an IBDV antibody titer of 4236 geometric mean (GM), whereas an antibody titer of 157 GM was measured in uninfected flocks. Infected flocks had very low (0.06) bursa-to-body-weight (BBW) ratio (an indicator of immunity) compared to high BBW ratio (0.17) in uninfected flocks, which suggests a significant immunosuppression in the former. Flocks positive for IBDV had mean mortality of 8.6% and mean condemnation of 1.5%. In contrast, mean mortality in uninfected flocks was 6.1% and mean condemnation was 1.1%. The live market weight per grow area at 37 d of age was 29.3 kg/m2in infected flocks and 34.0 kg/m2in flocks without IBDV infection. Flock mortality and condemnation rate were positively correlated with IBDV infection, whereas low BBW ratio was inversely correlated, as expected. Overall, IBDV-infected flocks had higher mortality, bursal atrophy, poorer feed conversion ratio (FCR), and decreased meat production. Our data suggest that the broiler chicken industry in Saskatchewan loses 3.9 million kilograms of meat production per year due to variant IBDV strains.
authors.affiliation: Department of Veterinary Pathology, Western College of Veterinary Medicine (Zachar, Popowich, Goodhope, Ahmed, Gomis), Department of Animal and Poultry Science, College of Agriculture and Bioresources (Knezacek), and Canadian Centre for Health and Safety in Agriculture, University of Saskatchewan, Saskatoon, Saskatchewan (Willson); Animal Health Laboratory, University of Guelph, P.O. Box 3612, Guelph, Ontario (Ojkic).
authors.forename: Tara
authors.initials: T
authors.lastname: Zachar
authors.affiliation: Department of Veterinary Pathology, Western College of Veterinary Medicine (Zachar, Popowich, Goodhope, Ahmed, Gomis), Department of Animal and Poultry Science, College of Agriculture and Bioresources (Knezacek), and Canadian Centre for Health and Safety in Agriculture, University of Saskatchewan, Saskatoon, Saskatchewan (Willson); Animal Health Laboratory, University of Guelph, P.O. Box 3612, Guelph, Ontario (Ojkic).
authors.forename: Shelly
authors.initials: S
authors.lastname: Popowich
authors.affiliation: Department of Veterinary Pathology, Western College of Veterinary Medicine (Zachar, Popowich, Goodhope, Ahmed, Gomis), Department of Animal and Poultry Science, College of Agriculture and Bioresources (Knezacek), and Canadian Centre for Health and Safety in Agriculture, University of Saskatchewan, Saskatoon, Saskatchewan (Willson); Animal Health Laboratory, University of Guelph, P.O. Box 3612, Guelph, Ontario (Ojkic).
authors.forename: Bob
authors.initials: B
authors.lastname: Goodhope
authors.affiliation: Department of Veterinary Pathology, Western College of Veterinary Medicine (Zachar, Popowich, Goodhope, Ahmed, Gomis), Department of Animal and Poultry Science, College of Agriculture and Bioresources (Knezacek), and Canadian Centre for Health and Safety in Agriculture, University of Saskatchewan, Saskatoon, Saskatchewan (Willson); Animal Health Laboratory, University of Guelph, P.O. Box 3612, Guelph, Ontario (Ojkic).
authors.forename: Tennille
authors.initials: T
authors.lastname: Knezacek
authors.affiliation: Department of Veterinary Pathology, Western College of Veterinary Medicine (Zachar, Popowich, Goodhope, Ahmed, Gomis), Department of Animal and Poultry Science, College of Agriculture and Bioresources (Knezacek), and Canadian Centre for Health and Safety in Agriculture, University of Saskatchewan, Saskatoon, Saskatchewan (Willson); Animal Health Laboratory, University of Guelph, P.O. Box 3612, Guelph, Ontario (Ojkic).
authors.forename: Davor
authors.initials: D
authors.lastname: Ojkic
authors.affiliation: Department of Veterinary Pathology, Western College of Veterinary Medicine (Zachar, Popowich, Goodhope, Ahmed, Gomis), Department of Animal and Poultry Science, College of Agriculture and Bioresources (Knezacek), and Canadian Centre for Health and Safety in Agriculture, University of Saskatchewan, Saskatoon, Saskatchewan (Willson); Animal Health Laboratory, University of Guelph, P.O. Box 3612, Guelph, Ontario (Ojkic).
authors.forename: Philip
authors.initials: P
authors.lastname: Willson
authors.affiliation: Department of Veterinary Pathology, Western College of Veterinary Medicine (Zachar, Popowich, Goodhope, Ahmed, Gomis), Department of Animal and Poultry Science, College of Agriculture and Bioresources (Knezacek), and Canadian Centre for Health and Safety in Agriculture, University of Saskatchewan, Saskatoon, Saskatchewan (Willson); Animal Health Laboratory, University of Guelph, P.O. Box 3612, Guelph, Ontario (Ojkic).
authors.forename: Khawaja Ashfaque
authors.initials: KA
authors.lastname: Ahmed
authors.affiliation: Department of Veterinary Pathology, Western College of Veterinary Medicine (Zachar, Popowich, Goodhope, Ahmed, Gomis), Department of Animal and Poultry Science, College of Agriculture and Bioresources (Knezacek), and Canadian Centre for Health and Safety in Agriculture, University of Saskatchewan, Saskatoon, Saskatchewan (Willson); Animal Health Laboratory, University of Guelph, P.O. Box 3612, Guelph, Ontario (Ojkic).
authors.forename: Susantha
authors.initials: S
authors.lastname: Gomis
mesh_terms: D000818:Animals; D001483:Base Sequence; D018175:Birnaviridae Infections / Q000191:economics / Q000453:epidemiology / Q000662:veterinary* / Q000821:virology; D002645:Chickens; D015994:Incidence; D007243:Infectious bursal disease virus / Q000235:genetics*; D010802:Phylogeny; D011201:Poultry Diseases / Q000191:economics / Q000453:epidemiology* / Q000821:virology; D012525:Saskatchewan / Q000453:epidemiology