The economic value of milk biomarkers: Ex-ante analysis of fat to protein ratio and fatty acid profile for the early detection of subacute ruminal acidosis in dairy cows

The key objective of this study was to develop a methodology to estimate the value of precision dairy farming monitoring systems (PDFMS) prior to implementation and, hence, in a situation of limited data availability. The second objective was to investigate which variables have the highest influence on the value of information (VOI) provided by PDFMS. To illustrate these objectives, we used a case-study of two milk biomarkers to monitor subacute ruminal acidosis (SARA) in dairy cows, the fat to protein ratio (FPR) and the fatty acid profile (FAP). A stochastic decision tree was designed to estimate the expected monetary value of: (i) not monitoring, monitoring with (ii) FPR, or (iii) FAP. The results suggest that under the most probable scenario not monitoring was a better decision than monitoring. Using FAP to detect SARA will be of value in herds with a prevalence between 0.24 and 0.80. While an improvement of the sensitivity of the FAP to 1 did not yield a positive VOI, an improvement of the specificity of the FAP to 1 did lead to a positive VOI.