mCytoCounter, a deployable somatic cell counting device for the assessment of mastitis in dairy farms

Abstract

Bovine mastitis is a recurring disease among herds that is often caused by unhygienic farm conditions, resulting in bacterial invasion of the udder. It is a leading cause of financial losses for dairy farmers, largely due to the widespread use of antimicrobials for treatment, which in turn fuels the development of drug-resistant bacteria. Somatic cell count (SCC) is a widely used quantitative method for diagnosing sub-clinical and clinical mastitis. We have developed a rapid and quantitative microfluidic device that enables the quantification of somatic cells in milk, thereby aiding in the diagnosis of bovine mastitis. Our platform features a microfluidic cartridge for capturing somatic cells, which is inserted into an in-house device called the mCytoCounter. The device reads the fluorescence emission signals from the somatic cells captured on the membrane in 2 minutes, with a total turnaround time of 15 minutes. The mCytoCounter is an automated and deployable system that can be used in dairy farms with minimal training. We analysed the performance of mCytoCounter with milk samples and benchmarked it against the SCC using a fluorescence microscope with a correlation coefficient of 0.97. The mCytoCounter has a detection range of 103 to 106 SCC/mL, which covers the required cell number range to discriminate between healthy, subclinical, and clinical mastitis.