Abstract:
The ideal milking machine harvests milk from dairy cows in a fast, effective manner without causing teat or udder damage, cow discomfort or loss in milk quality. Due to economic pressure many swing-over systems with high milk-lines were installed in South Africa, extending take-off delay with standard milking machine settings and increasing the risk of new intra-mammary infections.
The aim of the study was to investigate the effect of three automatic cluster removal (ACR) switch-point settings on machine-on time, over-milking duration, total average, peak flow- and over-milking vacuums. In a randomised trial using 65 (n = 65) performed on one dairy farm. Cows were selected based on their teat size, stage of lactation and udder palpation results. The trial cows were exposed for 15 milkings to each of three ACR switch-point settings (0.504 kg/min, 0.630 kg/min and 0.840 kg/min). The parlour was a 10-point, low-line, herringbone Waikato machine with the Afimilk system. Pre-milking preparations were observed while a VaDia-Biocontrol (Norway) apparatus was used to determine machine-on time and vacuums at the claw, mouthpiece and pulsator chambers during the whole milking process.
Results indicated that total machine-on time varied significantly (p < 0.05) between the 0.840 and 0.504 kg/min settings (290.0 to 289.2 sec) and between 0.630 and 0.504 kg/min (p < 0.01) (289.2 to 303.3 sec) settings respectively. Over-milking time differed significantly (p<0.0001) from 76.5 to 108.2 seconds between the highest and lowest volume setting. The three vacuum level measurements also differed significantly (p<0.0001) at each switch-point setting. Over-milking duration, as a percentage of total machine-on time, decreased from 35.7 % (at 0.504 kg/min) to 35.9 % (at 0.630 kg/min) and 26.4 % (at 0.840 kg/min) respectively.
The knowledge gained from different switch-point settings can be applied on individual dairy farms with different parlours and milking machines, to optimise settings in order to obtain a balance between milking efficiency and udder health.
