Development of a microwave sensor application for online detection of corn silage dry matter content

The moisture content of silages can be subjected to variations in time, leading to a potential decrease in dry matter (DM) content in the total mixed ration (TMR) and consequent impaired performance and health status in cows. With the purpose to maintain and improve the overall efficiency and the health of dairy cows, this study aimed to develop a new application in agricultural system for a commercial microwave sensor (MS) to online detect corn silage (CS) DM content. This would lead to the daily adjustment of the total amount of CS provided in the TMR based on its actual DM content, lowering performance fluctuations of cows. A calibration straight line for MS over CS samples was developed, following the sensor manufacturer instruction, from 75 dried samples experimentally rehydrated to reach 50-70% of moisture and the relative MS Quotient (emitted/residual energy) over four readings per sample was recorded. A Linear regression analysis showed a good correlation between Quotient and moisture content (r2=0.79). MS calibration was then tested against 22 CS fresh samples, subsequently analysed for DM (Reg. CE 152/2009). The linear regression analysis evidenced a good relationship between MS DM and lab DM results (r2=0.73), even if an offset of 9.60% with a slight difference in the slope of the straight lines (0.03 rad) was observed. A MS could be a promising tool to daily online monitor the DM content of CS, although further implementation in the number of samples for the calibration and the development of a correction coefficient for offset and slope of the straight line are needed to improve the accuracy. Funding was provided by the project P.L.U.S.- Precision Livestock Unifeed System (ID: 145923 CUP: E77H16001570009).