Immunoglobulin concentration and majors solids content of bovine colostrum can be accurately determined through mid-infrared spectroscopy

Colostrum has to be administered to calves as soon as possible after birth to permit the passive transfer of the immunity and avoid negative effects on survival and performance. Moreover, bovine colostrum is an emerging ingredient used by functional food manufacturers and pharmaceutical industry. The narrow-sense quality of colostrum relies on the concentration of immunoglobulins G (IgG), whose determination via gold standard is expensive and time consuming, making the analysis difficult to implement on a large-scale and/or in routine. In the present study we evaluated the predicting ability of mid-infrared spectroscopy (MIRS) as an indirect method for the assessment of IgG and gross composition traits in Holstein cows colostrum (n = 714) collected within 6 h from calving in 9 commercial farms located in Northern Italy. Reference values of IgG concentration and fat, protein, and lactose content were determined through radial immunodiffusion, Verbands Deutscher Land-wirdschaftlicher Untersuchungs und Forschungsanstalten VI C15.2.1 method, Kjeldahl, and high-performance liquid chromatograph, respectively. Spectral data, collected using a benchtop instrument (Milkoscan 7 RM, FOSS Electric A/S, Hillerød, Denmark), were used as predictor variables in the partial least square regression analyses. Both cross- and external validation were performed for each trait. Colostrum IgG, fat, protein, and lactose averaged 93.54 g/L, 14.71%, 4.61%, and 2.36 mg/100 mg with a coefficient of variation of 36.21, 23.86, 65.94, and 21.61%, respectively. Overall, the predictive ability of MIRS resulted promising. The coefficient of determination in external validation, in fact, ranged from 0.74 (fat) to 0.89 (protein) and was outstanding (0.84) for IgG. Root mean square errors were 13.39 (IgG), 1.16 (protein), 1.57 (fat), and 0.19 (lactose). Our findings represent a validation of the MIRS technology for a rapid and low-cost colostrum quality assessment and open the debate on the practicability of MIRS models implementation for acquisition of phenotypes of interest.