Development and testing of a “free-flow” conductimetric milk meter

Accurate milk yield measurement is important to maintain production efficiency and improve farm management: yield data enable to implement and evaluate feed rations for individual cows or groups, calculate actual lactation curves and identify potential health problems proactively. Nowadays, many electronic milk metering devices, based on different methods of measurement, are available on the market. Vacuum drop across the meter, accuracy over a wide range of flow rates and farm conditions (e.g. foaming of milk) are the key problems of currently available electronic milk meters. Aim of this project was the development of a free-flow milk meter, able to work with different flow rates and different combination of air-milk flows, with a measuring chamber essentially made by a portion of linear pipe, horizontally disposed and with no mechanical movement parts, to minimize the interferences with the milk flow and on the electric conductivity (EC), to calculate the milk yield, in order to obtain a low-cost device. A prototype was built up and laboratory and farm tests were carried out during 2004 and 2005, in order to evaluate the accuracy and reproducibility of the new device. Laboratory and farm tests were carried out following the guidelines of the International Committee for Animal Recording ICAR). Laboratory tests showed a bias of 1.4% and a standard deviation of 5.0%, while farm tests showed a bias of −4.5% and a standard deviation of 12.7%.