The concentration of major minerals in bovine bulk milk can be predicted using infrared spectroscopy

Bovine milk is a dietary source of important minerals. Moreover, major minerals such as Ca, Mg and P are known to be associated with milk technological properties related to cheese-making. On the other hand, Na and K levels in milk have been associated to problems at udder level and unbalanced diets. For such reasons, monitoring mineral composition of bulk milk during periodical milk quality controls is of great relevance for the livestock and cheese industry. Within the project ‘Innovamilk’ (‘Innovations in Italian dairy industry for the enhancement of farm sustainability, milk technological traits and cheese quality’) funded by AGER (Grant N° 20171153), the present study evaluated the possibility to use mid-infrared spectroscopy for the determination of milk Ca, Mg, P, K and Na content in bulk milk. For this purpose, bulk milk samples from 179 Holstein farms located in northern Italy were collected; the herd size ranged from 60 to 200. Herds were representative of different management systems, feeding rations, and milking equipment. Farms were sampled 1 to 5 times, during different seasons. For each bulk milk sample, infrared spectrum was collected using a mid-infrared spectroscopy device (FT7) and the concentration of each mineral was determined through the gold standard ICP-OES. Prediction models were developed applying different spectral pre-treatments and final equations were selected using cross-validation. Obtained results suggested that minerals of interest for the Italian dairy industry can be accurately predicted from bulk milk spectral data, with a determination coefficient in cross validation higher than 0.80.