The effect on workload by using a support arm in parlour milking
ABSTRACT Swedish agriculture is currently undergoing radical changes with respect to the working environment. New production milking systems may alter the physical workload and thus have an effect on the development of musculoskeletal disorders. Earlier studies have shown that there is a manifest risk of suffering injury to the forearm, wrist and hand during machine milking especially during the attaching task (when holding the milking cluster in one hand while attaching the four teat-cups to the udder). High degrees of dorsiflexion and deviation of the wrist in combination with peak values of muscle activity in the forearm during milking might contribute injuries to the wrist and hand. Large-scale milk production increases the time spent performing the tasks involved. As a consequence, the cumulative engagement in extreme positions and rapid movements, and high level of muscular load on the upper extremities will also increase. The aim of this study was to investigate the impact of the workload on the milker's forearm, wrist and hands resulting from using the prototype of a device designed to facilitate the attaching task. The device is constructed as a support arm where the milking cluster is suspended in order to reduce the workload. The study was carried out in a loose-housing system where the cows come to be milked in a parlour. Eleven milkers participated in the study. The muscle activity in the biceps and the forearm flexors, as well as positions and movements of the wrists were measured by electromyography and electrogoniometry. The attaching task was measured both with and without the device. When the prototype was used only a minor decrease in the muscular load on the holding side was recorded. Surprisingly, the effect on the wrist positions and movements was small. This marginal effect could be due to the fact that all the milkers were used to milking without the support arm and despite the training period, they were unable to make full use of the device.Relevance to industryA prototype of a technical device (support arm) has been developed in order to reduce the workload on the upper extremities, especially on the wrist and hand. The effect on the workload has been evaluated by electromyography and electrogoniometry. The results have shown that by milking with the support arm, the muscle activity has diminished in the upper extremities. This might reduce the occurrence of the work-related musculoskeletal injuries found in earlier studies of milkers at work in a loose-housing system.
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ABSTRACT: The purpose of this study was to evaluate the most common simultaneous and individual segment postures in terms of body and finger posture classifications. Observations were made at three dairy farms. One employed a tethering system and the other two used loose-housing systems. The evaluations of the tethering system were performed through six processes that were subdivided into 11 operations, whereas only one process of 'milking' was investigated in loose-housing systems. Generally, farmers who worked in both systems bent and/or twisted their upper-body segments and continuously used a power grasp to wrap an object with all five fingers. Posture analyses of the tethering system revealed that 'moving corn' seemed less stressful, whereas 'cleaning udders,' 'attaching the machine,' 'washing the machine,' and 'sweeping the floor' were more stressful than other operations. Postural workloads on the trunk and head were greater in the tethering system than in the loose-housing systems due to differences in implements, the working height, and the working distance.Applied ergonomics 12/2010; 42(1):1-8. · 1.11 Impact Factor
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ABSTRACT: Large-herd dairy operations utilize parlor milking systems that reduce the physical workload in comparison to tethering systems. Nevertheless, the number of musculoskeletal disorders among workers on dairy farms is not decreasing. In response, a study was carried out to measure the workload focusing on the impact of working height and weight of the milking unit. In this article a new quarter individual milking unit without claw and using single-tube guidance is compared with a light (1.4 kg) conventional unit. A significant reduction of muscular load as well as the reduction of process time was measured using the quarter individual system. Body posture was also recorded using video-based motion analysis. Based on these results, the new system is expected to significantly improve the work place in modern milking parlors by reducing extreme postures as well as the physical and static musculoskeletal load.Journal of Agromedicine 10/2011; 16(4):280-91. · 0.72 Impact Factor
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ABSTRACT: The incidence of work-related musculoskeletal disorders among milking parlor operatives has increased while milking parlors were getting bigger. At the same time parlor design was improved regarding the physical load as well as body postures. In contrast to former studies on workload in parlor milking this project was designed and performed as an experimental study in a laboratory setting including 6 female subjects. Motion analysis and psycho-physiological analysis (EMG, heart rate, subjective perceived strain index) were carried out. Intra-individual comparisons were made for the different settings using general linear models for repeated measurements. The effects of working height and weight of milking unit during parlor milking were investigated regarding the impact on muscular load and body posture. The results showed that the optimal working height for attaching the cluster is having the teats at shoulder level of the parlor operative. Another important workload reduction was achieved by reducing the weight of the milking cluster. The named discomfort, localized fatigue and the body posture analysis provide evidence that the changes in modern milking parlors due to mechanization still bear the risk of overburden for the worker.Applied ergonomics 12/2011; 43(4):753-61. · 1.11 Impact Factor