DETECTION OF CLINICAL MASTITIS BY CHANGES IN ELECTRICAL-CONDUCTIVITY OF FOREMILK BEFORE VISIBLE CHANGES IN MILK

Mastitis was induced by the direct infusion of Staphylococcus aureus o r Streptococcus uberis into the mammary gland of lactating cows. Chang es in electrical conductivity of foremilk indicated the establishment of bacteria, increased SCC, increased clotting of milk, and, hence, di sease, in advance of visible changes in the milk that could be diagnos ed by a herdsperson. Clinical mastitis was detectable by changes in el ectrical conductivity of foremilk, 90% of cases were detectable when c lots first appeared in foremilk, and 55% of cases were detectable up t o 2 milkings prior to the appearance of clots. All subclinical infecti ons from Staph. aureus were detected, but subclinical infections from Strep. uberis were not detected. The results suggested that clinical m astitis caused by these two major pathogens could be detected earlier by measuring changes in electrical conductivity of milk than by waitin g for a herdsperson to detect visible changes in milk. Earlier detecti on would permit earlier treatment. However, the handheld sensor used i n this experiment is impractical for commercial application, and relia ble automated sensors and decision-making algorithms are required.