Evaluation of teat-end vacuum conditions as affected by different pulsation settings in a quarter-individual milking system

The objective of this study was to determine the effect of pulsation on the teat-end vacuum behaviour in a quarter individual milking system (QIMS). To meet this objective, simultaneous (SIM), alternating (ALT) and sequential (SEQ) pulsation were tested in a laboratory milking parlour. In the pulsation system SEQ four pulsators, instead of one (as in SIM) or two (as in ALT), are used. Unlike in SIM and ALT, the pulsation in each quarter is started individually. After pulsation is started in quarter one, pulsation will begin in the following quarters, each with a time delay of 25 % of the pulse duration with respect to the start of the previous quarter. Tests were performed at various flow rates (0.8 to 6.0 l/min) with the help of the wet-test method and the teat-end vacuum behaviour was observed. The lowest vacuum fluctuation of 4.4 kPa was recorded under SIM pulsation as well as the lowest vacuum reduction of 1.3 kPa. Both values were recorded at a flow of 4 l/min during the suction phase (b-phase). For SEQ and ALT pulsation, higher levels of vacuum reduction and fluctuation were measured during the suction phase at a flow rate of 4 l/min (SEQ: 7.6 / 1.8 kPa and ALT: 9.0 / 1.9 kPa). Consequently, it was concluded that SIM pulsation is the most appropriate pulsation setting when optimization for low vacuum reduction and fluctuation during the suction phase is demanded.