Effect of hydraulic milking on milking performance, teat condition and lipolysis

Abstract

The term 'hydraulic milking' describes a new milking concept in which liner movement is restricted and the liner is flooded with milk beneath the teat. This condition, achieved with a multi-valve claw without air admission to the cluster, reduced milking time by 26% and increased milk flow rate by 20%. Four experiments describe the discovery of hydraulic milking and investigate its potential using equal or different levels of vacuum in the milkline and pulseline. Benefits from hydraulic milking include decreased lipolysis (<36%) and milk foam (75%), improved teat condition and a high degree of protection against machine-induced infections. Evidence of increased milk yield is inconclusive. Cluster removal is impeded by hydraulic milking and the multi-valve cluster requires modification to facilitate the process. Pulsation characteristics and vacuum levels developed for conventional milking appear adequate for hydraulic milking. Unorthodox vacuum conditions may be needed, however, to exploit fully this novel milking concept.The multi-valve claw (Griffin et al. 1988) incorporates non-return ball valves which prevent inter-teatcup transfer of milk and air and thus provide positive protection against impacts and cross-contamination Thiel et al. 1973). When the multi-valve clawpiece was used in commercial herds that had adopted other mastitis control measures the new udder infections were lower by 14% and new clinical cases by 25% compared with milking with conventional machines. The reductions were not statistically significant (P > O10) because of marked variation between herds (Griffin et al. 1988).To obtain a milking action similar to that with a conventional cluster the claw air bleed was replaced with an air bleed in each short milk tube (SMT). This increased air admission (14 1/min v. 7 1/min) slightly reduced operating vacuum, increased milking times and led to a small increase in milk lipolysis (Needs et al. 1986).To investigate these aspects and obtain information on the effect of air bleed blockage during farm use, experiments were performed in which the SMT air bleeds were omitted when using the multi-valve cluster. Under these conditions the liners and SMT were constantly flooded during milking. Because all the forces applied to the teat end within the liner are through a solid column of milk the new milking principle has been designated 'hydraulic milking'.• Present address: 8 Harold Close, Lower End, Leafield, Oxon. 0X8 9XX.

Automatic application of teat disinfectant through the milking machine cluster

“…Infusion of disinfectant into the mouthpiece chamber, just before cluster removal, reduces the level of vacuum within the liner mouthpiece, overcomes the friction at the mouthpiece lip and facilitates removal of the cluster. This may be particularly important with hydraulic milking systems (Grindal & Griffin, 1989).…”