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.
"A tethering system, at a stanchion barn, is a traditional milking method that requires a worker to carry a milking machine to a cow and crouch in a squatting posture to install approximately 6 kg of milking equipment. In contrast, in a loose-housing system, which involves tandem and/or herringbone parlors among others, the method of milking is advanced whereby a worker can milk cows at a standing posture due to a revised workstation, as seen in Fig. 1 (Stål et al., 2003). In a loose-housing system, a tandem parlor allows cows to come in one-by-one, whilst a herringbone parlor can have a group of cows enter simultaneously. "
[Show abstract][Hide abstract] 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.
"While the number of livestock farms in Sweden has decreased considerably, the herd sizes have increased noticeably during the last 10 years (Statistics Sweden 2005). Along with the structural changes there has been a substantial development especially in machine milking systems and this has helped to reduce the workload (Nevala-Puranen et al. 1996; Stål et al. 2003a). Only a few studies can be found regarding the impact of the workload on MSD among stockmen working with pigs (Hartman et al. 2000; Stål et al. 2005a). "
[Show abstract][Hide abstract] ABSTRACT: The most frequently reported musculoskeletal disorders among dairy and pig stockmen were in the "upper extremities" (52% and 62%, respectively) and in "the back" (60% and 57%, respectively). Furthermore, milking was the most time-consuming task (15 hours/week) among the dairy stockmen and also the task with the highest Physical Work Strain index (PWS 1.46). Among the stockmen on the pig farms the most time-consuming task was removal of manure occupying 10 hours/week and it was also the most physically demanding work task (PWS 0.86). 1 Introduction Several national and international studies have shown that animal farming can cause musculoskeletal disorders (MSD) and the most common reasons for this are associated with a heavy workload, repetitive strenuous movements, and poor working postures (Lundqvist 1988; Pinzke 1999; Stål 1999; Hartman et al. 2000; Walker-Bone & Palmer 2002; Holmberg 2004; Stål & Englund 2005a). While the number of livestock farms in Sweden has decreased considerably, the herd sizes have increased noticeably during the last 10 years (Statistics Sweden 2005). Along with the structural changes there has been a substantial development especially in machine milking systems and this has helped to reduce the workload (Nevala-Puranen et al. 1996; Stål et al. 2003a). Only a few studies can be found regarding the impact of the workload on MSD among stockmen working with pigs (Hartman et al. 2000; Stål et al. 2005a). Despite these technical advances in large livestock farming, stockmen still report high frequencies of MSD.
[Show abstract][Hide abstract] ABSTRACT: Introduction: The US dairy industry has experienced a relatively rapid transformation from small herd farms to the industrialization of milking operations. This agricultural transformation has led to significant changes in work tasks for dairy parlor workers and in ergonomic challenges due to the highly repetitive nature of the industrialized work. The purpose of this feasibility study was to evaluate the usefulness of full-shift quantitative exposure assessment tools for assessing posture and muscle activity among large herd parlor workers. Methods: Study participants were recruited from large herd dairy operations in the United States. Shoulder elevation and trunk inclination angles were estimated using triaxial accelerometers. Surface electromyography (EMG) was sampled continuously during the entire work shift while workers performed milking parlor tasks. Electromyography samples were composed of recordings of the upper trapzezius, finger flexors, finger extensors and anterior deltoid (shoulder flexor). Results/Conclusions: Results suggest that parlor workers are exposed to extreme exposures (awkward postures, high movement velocities, high repetition, high muscle forces). These physical exposures are often associated with the development of upper limb pathology. These findings warrant the continued research of full-shift work tasks and ergonomic interventions within the working environments of dairy parlors.
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