Minerals and essential amino acids of bovine colostrum: phenotypic variability and predictive ability of mid- and near-infrared spectroscopy

: Colostrum quality and volume are fundamental for calves since it is the primary supplier of antibodies and the first source of energy, carbohydrates, lipids, proteins, minerals, and vitamins for the newborn. Assessing the detailed composition (i.e., AA and mineral content) of bovine colostrum (BC) on-line and at a reasonable cost would help dairy stakeholders like farmers or veterinarians for precision feeding purposes and industries producing preparations containing BC such as foodstuff, supplements, and medicaments. In the present study we evaluated mid- (MIRS) and near-infrared spectroscopy (NIRS) prediction ability for AA and mineral composition of individual BC. Second, we the investigated the major factors affecting the phenotypic variability of such traits also evaluating the correlations with Ig. Results demonstrated that MIRS and NIRS were able to provide sufficient to accurate predictions of all the AA (0.70 ≤ R2V ≤ 0.86) with the exception of Ile, His, and Met, but only some minerals reached a sufficient accuracy, i.e., i.e., Ca, P, S, and Mg (R2V ≥ 0.66) using MIRS, and also S (R2V = 0.87) using NIRS. Phenotypically, both parity and calving season affected the variability of detailed colostrum composition, with heifers having colostrum with greatest concentration of Ca and P, the 2 most abundant minerals. These minerals were however very low in cows calving in summer compared with the rest of the year. The pattern of AA across parities and calving season were not linear and difficult to explain, likely because their variability was scarcely (or not) affected by these effects. Finally, colostrum samples characterized by high IgG concentration were those presenting on average greater concentration of AA. Findings suggest that infrared spectroscopy has the potential to be used to predict certain AA and minerals, outlining the possibility of implementing on-site analyzes for the evaluation of broad-sense qualitative parameters.