Plasmin measurement as a new diagnosis test for mastitis in dairy cattle

Abstract

Mastitis is a major economic issue in dairy cattle. It causes high economic losses due to veterinary costs, milk which can't be used for consumption and due to decreased production and increased culling rates. Current tests like somatic cell count, electrical conduction and CMT-test are not always reliable. There are regularly false negative and false positive results so that there is need for new diagnostic tests. The objective of the present study was to determine test characteristics of plasmin substrates as a diagnostic test for clinical mastitis in dairy cattle. One quarter of 180 different cows was sampled by hand milking. The somatic cell count and electrical conductivity were determined for each sample.Then buffer, sampled milk coming from one cow and substrate are put together. This mix is incubated and after that the mindling is placed in the Fluostar for one hour. The plasmin, a protease, begins to cut the substrate what leads to the release of électrons what can be measured. A significant difference in increased fluorescence was measured between cows without and cows with mastitis. This was done by compare the increased fluorescence from samples of milk from apparently healthy cows with those with mastitis. The aera Under the curve was 0,760. When looking at the threshold-value 14,86, a sensitivity of 81% and specificity of 61% are found. It was also seen that there is a correlation between plasmin concentration and somatic cell count (SCC) and a negative correlation between plasmin concentration and electric conductivity (EC).