The demands of quality and choice in the dairy industry require analysis of extended performance. Ancient milk protein measuring devices take a long time and provide slow and inaccurate results. This work is part of the reliable analysis of cow’s milk proteins and defines the laws linking the two parameters, total nitrogen (NT) and protein nitrogen (NP). We are studying to prove a fast and effective method for measuring the non-protein nitrogen (NPN) composition of milk that allows the direct calculation of NP from the NT value, whose objective is to adapt the calibration of the Milko Scan FT2 cow’s milk protein analysis since NPN has a direct impact on protein analysis, payment of milk, and on the manufacture of milk products. The study showed that there is a compatibility between these two parameters and gave an idea of the percentage (5.9%) of NPN in milk. New analytical solutions such as the latest generation of the Kjeldahl K-375/376 and the new Milko Scan FT2 meet these needs. Data processing is done using XLSTAT, which is free statistical analysis software.