A milking system includes a milking device with a milking control, a milk line, and a sampling/analysis device. The milking control controls the milking based on said analysis. The sampling/analysis device includes a reagent carrier, including a tape with a first side with a reagent pad that detects the presence of a substance in the milk sample and a second side, a dosing device to provide a droplet of said sample onto the reagent pad, a source for emitting source radiation onto the reagent pad, and a sensor to detect response radiation emitted by the reagent pad, and to analyse the detected response radiation to indicate the presence or concentration of said substance. The first side faces away from the sensor during analysing by the sensor. By viewing “from below”, the observed reaction in the reagent is cleaner, and suffers less from artefacts, and the camera will stay cleaner.