Towards a new measurement method for urine puddle volume in dairy cow houses using fluorescense

Drainage of urine from concrete floors in dairy housing reduces the ammonia emission. Surface area of a urine puddle and puddle depth are among the five most determining parameters predicting ammonia emission. However a validated
method to estimate the amount of urine present on the floor at any time to characterize the drainage process of urine in practice is lacking. We propose a new method to estimate puddle volume based on measuring intensity of emitted light from a simulated urine puddle with a known concentration of soluble fluorescing tracer after exposure with light of an appropriate wavelength. To develop this new method an installation was constructed consisting of blue and white LED lights, a 1.4 MP 14-bit CCD camera and different filters. Calibrations of pixel size and flat field corrections were performed. Essential for this approach is an accurate calibration line between the amount of tracer and the intensity of emitted fluorescence light for use in field measurements. Objective of the research presented here was to establish a calibration line for different combinations of tracer concentration and layer thicknesses under controlled conditions. According to theoretical background a linear relationship between amount of a fluorescence tracer present and the fluorescence light intensity could be established.