Assessment of mastitis risk by measuring somatic cells in milk using resistive pulse sensing-based particle counting

The economic loss caused by mastitis in dairy cows is extremely large worldwide and remains an issue where improvement is needed. The focus of this study was on-site measurement technology. We evaluated the usefulness of resistive pulse sensing (RPS) particle measurement in comparison with standard measurement and the clinical findings of udder quarters in cows. We measured the particle count in milk samples collected from healthy udder quarters, calculated statistically normal values, and judged cases with significantly deviated values as abnormal. We found that abnormal values detected using RPS measurement corresponded to those using standard measurement. Furthermore, it was possible to identify which specific udder quarter was causing the abnormality, and this matched the abnormalities observed in clinical findings. RPS also enabled the detection of subclinical abnormalities in udder quarters showing no visible symptoms. RPS is a simple particle measurement method, and it cannot be used to diagnose disease directly; however, its use on-site can facilitate the early detection of abnormalities and help to maintain milk quality. Because the device used in RPS mainly measures electrical current, it can be manufactured at low cost, making RPS a promising tool for future point-of-care testing.