Exploratory analysis of dynamics of frequency distribution of raw cow milk quality indicators in the Czech Republic

Abstract

A consistent link of the raw milk quality (RMQ) to the farmer price is essential. The aim was to analyse the properties of milk quality indicators (MQIs) and propose a new synthetic relative MQI (SQSM) from among various individual MQIs. SQSM could serve for consistent inclusion each quality change into the price. The paper was focused on exploratory analysis (normality (N) testing of files of MQIs). On the basis of the results, the MQIs were divided into two groups without and with necessity of original data transformation (TRN). Log and Box–Cox TRNs were tested in terms of possibilities of the files approach to the normal data frequency distribution (FD). The compositional MQIs deviated less and health and hygienic MQIs more from normal FD in original data (P < 0.05). The TRNs approached the data files to N very markedly in health and hygienic MQIs. The synthesis of various values of MQIs into SQSM was proposed. SQSM values were derived from model file of real data about MQIs and validated for use at farmer milk price modifications by the normality FD test. 33.3% of month SQSM files were normal (P > 0.05), the other were very close to the N with negligible deviations. The useability of the SQSM system for the balancing of raw milk purchase price premiums and penalties was tentatively confirmed.