Infrared spectroscopic methods for the discrimination of cows' milk according to the feeding system, cow breed and altitude of the dairy farm

Bulk milk samples were collected from four French regions to study the potential capability of mid-infrared (MIR) and near-infrared (NIR) spectroscopy data to differentiate milk according to the feeding system, breed of cow and altitude of the farm. The MIR method demonstrated an excellent capability to distinguish milk from hay- and pasture-based systems and those from maize silage- and pasture-based systems. The MIR method did not exhibit the same capability concerning the discrimination of milk from hay- and maize silage-based systems. A similar trend was observed with the NIR method but with lower efficiency. The two infrared methods did not satisfactorily discriminate milk from different cow breeds. Significant differences (P < 0.05) between methods in the proportion of correctly classified samples according to the feeding system and breed were reported, whereas no significant differences were found between the methods concerning the discrimination of lowland versus upland samples.