Effects of milking machine parameters on the mean milk flow rate in a robotic milking system

Abstract

In this experiment the focus was on the machine on time needed for the milk removal process. This experiment aimed to examine the effect of four milking machine treatments on the mean milk flow rate. In the four test situations the milking machine settings were: A) milking- and pulsation vacuum 42 kPa; pulsation ratio 65/35; pulsation rate 58 cycles per minute; detachment level 200 g per minute; B) Settings as in A except the detachment level was increased from 200 to 350 g per minute; C. Settings as in B except the vacuum level was increased from 42 to 45 kPa; D. Settings as in C except the pulsation ratio varied between 55/45 and 70/30 depending on the actual milk flow rate. Treatments A, B, C and D were applied during three 16-d periods. In a 16-d period each treatment was used for 4 consecutive days. The order of the test situations differed in each 16-d period. The experiment was carried out in a two-box robotic milking system (Prolion). Cows were accepted for milking 6 hours after the previous milking visit. When intervals became longer than 12 hours cows were fetched. During each milking visit 0.5 till 2.0 kg of concentrates were fed. Data from 54 cows that were on the system during the three test periods were analyzed. The mean milk flow rates differed significantly (p < 0.05) between all treatments and were 1.65, 1.81, 1.90 and 1.84 kg per minute for respectively the A, B, C and D treatment. With higher milk yields (range 3-18 kg) and longer attachment durations (range 45-120 s) per milking milk flow rates increased significantly. Reactions on the treatments of individual cows sometimes showed clear deviations from the general trends.