title: Measurement of serum immunoglobulin G in dairy cattle using Fourier-transform infrared spectroscopy: a reagent free approach.
abstract: Simple, rapid and cost-effective methods are sought for measuring immunoglobulin G (IgG) concentrations in bovine serum, which can be applied for diagnosis of failure of transfer of passive immunity (FTPI). The aim of the present study was to investigate the potential use of Fourier-transform infrared (FTIR) spectroscopy, with partial least squares (PLS) regression, to measure IgG concentrations in bovine serum. Serum samples collected from calves and adult cows were tested in parallel by radial immunodiffusion (RID) assay and FTIR spectroscopy. The sample IgG concentrations obtained by the RID method were linked to pre-processed spectra and divided into two sets: a combined set and a test set. The combined set was used for building a calibration model, while the test set was used to assess the predictive ability of the calibration model, resulting in a root mean squared error of prediction (RMSEP) of 307.5 mg/dL. The concordance correlations between the IgG measured by RID and predicted by FTIR spectroscopy were 0.96 and 0.93 for the combined and test data sets, respectively. Analysis of the data using the Bland-Altman method did not show any evidence of systematic bias between FTIR spectroscopy and RID methods for measurement of IgG. The clinical applicability of FTIR spectroscopy for diagnosis of FTPI was evaluated using the entire data set and showed a sensitivity of 0.91 and specificity of 0.96, using RID as the reference standard. The FTIR spectroscopy method, described in the present study, demonstrates potential as a rapid and reagent-free tool for quantification of IgG in bovine serum, as an aid to diagnosis of FTPI in calves.
authors.affiliation: Department of Health Management, Atlantic Veterinary College, University of Prince Edward Island, 550 University Avenue, Charlottetown, Prince Edward Island C1A 4P3, Canada; Infectious Diseases, Department of Animal Medicine, Faculty of Veterinary Medicine, Zagazig University, Zagazig City 44511, Sharkia Province, Egypt. Electronic address: ielsohaby@upei.ca.
authors.forename: Ibrahim
authors.initials: I
authors.lastname: Elsohaby
authors.affiliation: Department of Health Management, Atlantic Veterinary College, University of Prince Edward Island, 550 University Avenue, Charlottetown, Prince Edward Island C1A 4P3, Canada; Institute of Veterinary, Animal and Biomedical Sciences, Massey University, Palmerston North 4442, New Zealand.
authors.forename: Christopher B
authors.initials: CB
authors.lastname: Riley
authors.affiliation: Department of Health Management, Atlantic Veterinary College, University of Prince Edward Island, 550 University Avenue, Charlottetown, Prince Edward Island C1A 4P3, Canada.
authors.forename: Siyuan
authors.initials: S
authors.lastname: Hou
authors.affiliation: Department of Health Management, Atlantic Veterinary College, University of Prince Edward Island, 550 University Avenue, Charlottetown, Prince Edward Island C1A 4P3, Canada.
authors.forename: J Trenton
authors.initials: JT
authors.lastname: McClure
authors.affiliation: National Research Council of Canada, Medical Devices Portfolio, Winnipeg, Manitoba R3B 1Y6, Canada.
authors.forename: R Anthony
authors.initials: RA
authors.lastname: Shaw
authors.affiliation: Department of Health Management, Atlantic Veterinary College, University of Prince Edward Island, 550 University Avenue, Charlottetown, Prince Edward Island C1A 4P3, Canada.
authors.forename: Gregory P
authors.initials: GP
authors.lastname: Keefe
mesh_terms: D000818:Animals; D000831:Animals, Newborn / Q000276:immunology*; D002417:Cattle / Q000254:growth & development / Q000276:immunology*; D005260:Female; D007112:Immunity, Maternally-Acquired; D007074:Immunoglobulin G / Q000097:blood*; D007202:Indicators and Reagents / Q000032:analysis; D016018:Least-Squares Analysis; D012680:Sensitivity and Specificity; D017550:Spectroscopy, Fourier Transform Infrared / Q000662:veterinary*
chemical_list: D007074:Immunoglobulin G; D007202:Indicators and Reagents
keywords: Dairy calves; Failure of passive transfer of immunity; Fourier-transform infrared spectroscopy; Partial least squares regression; Radial immunodiffusion assay