Transmission infrared (IR) spectroscopy, in combination with partial least squares (PLS) regression, was used as the basis to develop a new method to quantify IgG in bovine colostrum. Colostrum samples (n = 250) were tested simultaneously by the reference radial immunodiffusion (RID) assay and IR spectroscopy. Colostral IgG concentrations obtained by RID assay were linked to pre-processed spectra and divided into two sets, i.e., calibration and test. PLS regression was applied to the calibration set and calibration models were developed, and the test set was used to assess the accuracy of the analytical method. The Pearson and concordance correlations between test set IgG concentrations as determined by the IR assay and the RID assay were 0.91. The Bland-Altman plot showed no evidence of systematic bias between IR and RID methods. Transmission IR spectroscopy is an effective method for quantification of bovine colostral IgG concentration and for assessment of colostrum quality.
International Dairy Journal52 (24 August 2015): 35–41.