Full-shift and task-specific upper extremity muscle activity among US large-herd dairy parlour workers

On-Farm Health Screening Needs of Immigrant Dairy Workers in the Texas Panhandle and South Plains

The objective of this pilot study was to determine the health needs of dairy farm workers and the feasibility of on-farm health risk screenings in the Texas Panhandle and South Plains. A cross-sectional study design was used to collect survey responses concerning health needs, occupational, and economic characteristics among 300 dairy workers between April 2020 and July 2021. Participants were predominantly immigrant Hispanic (88.8%) males (83.0%) of approximately 34.4 (SD 9.9) years of age, worked 6.0 (SD 0.4; Range 3-7) days a week and 9.9 (SD 1.5; Range 6-13) hours a day, earning a mean hourly rate of $13.40 (SD $2.80). Participants reported interest in attending on-farm health risk screenings (93.8%) as well as receiving a COVID-19 vaccine if it became available (86.4%). Health service categories were ranked from: (1st "most important") preventative care (Mean Rank 2.3), (2nd) laboratory and diagnostic care (Mean Rank 2.6), (3rd) nutritional and physical fitness support (Mean Rank 2.8), (4th) mental health care (Mean Rank 3.4), and (5th) workplace interventions (Mean Rank 3.6). Participants reported obtaining health information predominantly from internet searches (32.0%) and social media (17.7%). Findings suggest there is need and interest for on-farm health risk screenings and education among immigrant dairy workers in the Texas Panhandle-South Plains region. Addressing known barriers to health should be paramount to the organization of on-farm health risk screenings.

Biomechanical Assessments of the Upper Limb for Determining Fatigue, Strain and Effort from the Laboratory to the Industrial Working Place: A Systematic Review

Recent human-centered developments in the industrial field (Industry 5.0) lead companies and stakeholders to ensure the wellbeing of their workers with assessments of upper limb performance in the workplace, with the aim of reducing work-related diseases and improving awareness of the physical status of workers, by assessing motor performance, fatigue, strain and effort. Such approaches are usually developed in laboratories and only at times they are translated to on-field applications; few studies summarized common practices for the assessments. Therefore, our aim is to review the current state-of-the-art approaches used for the assessment of fatigue, strain and effort in working scenarios and to analyze in detail the differences between studies that take place in the laboratory and in the workplace, in order to give insights on future trends and directions. A systematic review of the studies aimed at evaluating the motor performance, fatigue, strain and effort of the upper limb targeting working scenarios is presented. A total of 1375 articles were found in scientific databases and 288 were analyzed. About half of the scientific articles are focused on laboratory pilot studies investigating effort and fatigue in laboratories, while the other half are set in working places. Our results showed that assessing upper limb biomechanics is quite common in the field, but it is mostly performed with instrumental assessments in laboratory studies, while questionnaires and scales are preferred in working places. Future directions may be oriented towards multi-domain approaches able to exploit the potential of combined analyses, exploitation of instrumental approaches in workplace, targeting a wider range of people and implementing more structured trials to translate pilot studies to real practice.

Commonly Used Subjective Effort Scales May Not Predict Directly Measured Physical Workloads and Fatigue in Hispanic Farmworkers

In North America, Hispanic migrant farmworkers are being exposed to occupational ergonomic risks. Due to cultural differences in the perception and reporting of effort and pain, it was unknown whether standardized subjective ergonomic assessment tools could accurately estimate the directly measured their physical effort. This study investigated whether the subjective scales widely used in exercise physiology were associated with the direct measures of metabolic load and muscle fatigue in this population. Twenty-four migrant apple harvesters participated in this study. The Borg RPE in Spanish and the Omni RPE with pictures of tree-fruit harvesters were used for assessing overall effort at four time points during a full-day 8-h work shift. The Borg CR10 was used for assessing local discomfort at the shoulders. To determine whether there were associations between the subjective and direct measures of overall exertion measures, we conducted linear regressions of the percentage of heart rate reserve (% HRR) on the Borg RPE and Omni RPE. In terms of local discomfort, the median power frequency (MPF) of trapezius electromyography (EMG) was used for representing muscle fatigue. Then full-day measurements of muscle fatigue were regressed on the Borg CR10 changes from the beginning to the end of the work shift. The Omni RPE were found to be correlated with the % HRR. In addition, the Borg RPE were correlated to the % HRR after the break but not after the work. These scales might be useful for certain situations. In terms of local discomfort, the Borg CR10 were not correlated with the MPF of EMG and, therefore, could not replace direct measurement.

Machine learning methods for electromyography error detection in field research: An application in full-shift field assessment of shoulder muscle activity in apple harvesting workers

This study presented an alternative technique for processing electromyography (EMG) data with sporadic errors due to challenges associated with the field collection of EMG data. The application of this technique was used to detect errors, clean and optimize EMG data in order characterize and compare shoulder muscular load in farmworkers during apple harvesting in a trellised orchard. Surface EMG was used to take measurements from twenty-four participants in an actual field work environment. Anomalies in the EMG data were detected and removed with a customized algorithm using principal component analysis, interquartile range cut-off and unsupervised cluster analysis. This study found significantly greater upper trapezius muscle activity in farmworkers who used a ladder as compared to the alternative platform-based method where a team of mobile platform workers harvested apples from the tree tops and a second separate team of ground workers harvested apples from the tree bottoms. By comparing the unprocessed and the processed, anomaly-free EMG data, the robustness of our proposed method was demonstrated.

A Scoping Review of Safety and Health Interventions in the High-Risk Dairy Industry: Gaps in Evidence Point to Future Directions in Research

The occupational injury rate of the dairy industry (6.6 per 100 full-time workers) is twice that of the national average across all industries (3.3 per 100 full-time workers). While dairy farms are becoming larger in size and fewer in number, this rate has not changed. A scoping review was conducted to identify published reports of occupational safety interventions in the dairy industry. An additional criterion was that the study included an evaluation of the intervention. Out of 22 articles that met the first criterion (discussion of interventions specific to the dairy industry), 19 met the second of having an evaluative component. These 19 articles corresponded to 16 unique studies, because 4 articles corresponded to the same study. Of the 16 unique studies, only 3 had a comparison of treatment vs. control effects, and none measured the impact of the intervention on injuries and fatalities. Of the 16 interventions, 6 were focused on training or informational campaigns in which the evaluations primarily measured knowledge acquisition. Additionally, none of these studies had a sufficient sample size to compare injury rates as an outcome. Our study demonstrates that the literature lacks any rigorous evaluation of whether dairy safety interventions are making an impact on injury prevention. Given this, it is not possible to determine how work-related injuries and deaths can be prevented in the dairy industry. Recommendations for future research include incorporating rigorous evaluation into research designs and attempting to develop low-cost, unobtrusive methods for collecting data on intermediate and final outcomes.

Opportunities for improving the safety of dairy parlor workers

One aspect of a successful dairy business is attracting and retaining skilled staff. The ability to do this is influenced by workplace attractiveness, one aspect of which is worker comfort and safety. Working with heavy machinery and animals makes dairy farming a dangerous occupation relative to many other sectors. Milking is the most time-consuming task on pasture-based dairy farms, and the parlor is the logical site of a number of injuries, although little is known about their causes or their relationship to parlor design and management. To investigate worker safety further, we conducted an on-farm survey on New Zealand dairy farms between December 2018 and March 2019. The survey had 3 objectives: to identify common causes of injuries relating to milking; to describe variations in milking parlor design and management practices on dairy farms; and to identify management and parlor factors that contribute to milking injuries. Analysis of accident compensation data from the state-run accident insurer for a 5-yr period from July 2013 to June 2018 was a fourth objective. Accident claims identified as related to milking through a key word search averaged NZ$252 (NZ$1 was equivalent to US$0.60 on May 19, 2020) per claim for non-severe injuries and NZ$9,334 per claim for severe injuries, for a total of NZ$1.95 million per year. A total of 136 injuries were reported on 99 of the 560 farms surveyed, and accident insurance claims were made for 53 of these injuries. The survey found that 48% of injuries occurred while workers were attaching clusters: typically soft-tissue and fracture injuries to fingers, hands, wrists, and arms. Injuries to these body parts represented the greatest cost (51% of the annual insurance cost) and identified safe cluster attachment as an area of focus for reducing milking injuries. Potential low-cost solutions include improved cluster design and a hand-arm guard. We identified a clear seasonal trend that coincided with busy periods in a seasonal block calving system, suggesting that options to reduce fatigue in spring may be beneficial; however, the number of hours worked or number of consecutive days worked were not associated with the number of milking injuries. Those aged 20-29 yr had more injuries relative to their proportion of the workforce, indicating that more training may be beneficial (e.g., setting ergonomic milking routines). Female workers were at greater risk of injury than males; this finding may have been related to the height of the animal relative to the height of the milker.

Biomechanical factors during common agricultural activities: Results of on-farm exposure assessments using direct measurement methods

Agricultural work is associated with increased risk of adverse musculoskeletal health outcomes. The purpose of this study was to quantify exposure to biomechanical factors among a sample (n = 55) of farmers in the Midwest region of the U.S. while they performed a variety of routine agricultural activities, and to compare exposure levels between these activities. Surface electromyography was used to estimate activity levels of the erector spinae, upper trapezius, forearm flexor, and forearm extensor muscle groups. Simultaneously, inertial sensors were used to measure kinematics of the trunk, upper arm, and wrist. In general, lower muscle activity levels, less extreme postures, and slower movement speeds were observed during activities that involved primarily the use of agricultural machinery in comparison to manual activities, suggesting a potential advantage of mechanization relative to musculoskeletal health. Median wrist movement speeds exceeding recently proposed exposure thresholds were also observed during many manual activities, such as milking animals and repairing equipment. Upper arm postures and movement speeds did not appear to confer excessive risk for shoulder-related outcomes (on the whole), but interpretation of the results is limited by a sampling approach that may not have captured the full extent of exposure variation. Not surprisingly, substantial variation in exposure levels were observed within each agricultural activity, which is related to substantial variation in the equipment, tools, and work practices used by participants. Ultimately, the results of this study contribute to an emerging literature in which the physical demands of routine agricultural work have been described on the basis of sensor-based measurements rather than more common self-report or observation-based approaches.

Personal and occupational factors contributing to biomechanical risk of the distal upper limb among dairy workers in the Lombardy region of Italy

Biomechanical overload in the wrist flexor and extensor muscles, together with awkward hand positions during work activities, can result in occupational wrist and hand disorders. Dairy workers, specifically those that work in the milking parlor, are exposed to highly repetitive and forceful exertions of the upper limb throughout their work shift. There are very few studies that have investigated the determinants that contribute to the risk of distal upper limb musculoskeletal disorders among dairy workers. The purpose of the present study was to identify the variables affecting the biomechanical overload of the distal upper limb among milking parlor workers, define risk profiles, and propose possible interventions to reduce the high physical loads to the distal upper limb during milking activities. Forty male workers from the three most common milking parlor systems in Lombardy Italy were recruited to participate in this study. Multiple correspondence analysis of personal characteristics and occupational risk factors, followed by cluster analysis, led to the identification of three distinct groups of workers. Low, medium and high risk profiles were assigned to each group based on the risk assessments performed using the Strain Index and electromyography of the distal upper limb. The main risk determinants were workstation characteristics, work organization and milking routine. A well-organized milking routine, milking cluster weight below 2.4 kg or the use of supporting arms for the milking cluster may reduce the risk of biomechanical overload.

Evaluation of upper body kinematics and muscle activity during milking attachment task

The objective of the study was to evaluate the effects of udder height on upper body kinematics and muscle activity during a simulated attachment task in a parallel parlor set up, and the effects of udder access method (back or side) on the task biomechanics. Twenty males performed the task under conditions that simulated three udder heights and two udder access methods. The muscular load and kinematics during the task confirmed that milking is a physically demanding task. Trunk flexion angle increased with decreasing udder height, and the erector spinae activation was higher when the udder was below shoulder height compared to at or above. Compared to accessing the udder from side of the cow (herringbone parlor style), accessing from behind (Parallel parlor style) was associated with lower trunk flexion, greater shoulder horizontal adduction, lower shoulder elevation, and greater anterior deltoid activation. Milking in herringbone parlor style and with the udder at or above shoulder level may help reduce strain on the trunk/neck.

Size, Composition, and Source Profiles of Inhalable Bioaerosols from Colorado Dairies

Particulate matter emissions from agricultural livestock operations contain both chemical and biological constituents that represent a potential human health hazard. The size and composition of these dusts, however, have not been well described. We evaluated the full size distribution (from 0 to 100 μm in aerodynamic diameter) and chemical/biological composition of inhalable dusts inside several Colorado dairy parlors. Four aerodynamic size fractions (<3, 3-10, 10-30, and >30 μm) were collected and analyzed using a combination of physiochemical techniques to understand the structure of bacterial communities and chemical constituents. Airborne particulate mass followed a bimodal size distribution (one mode at 3 μm and a second above 30 μm), which also correlated with the relative concentrations of the following microbiological markers: bacterial endotoxin, 3-hydroxy fatty acids, and muramic acid. Sequencing of the 16S-rRNA components of this aerosol revealed a microbiome derived predominantly from animal sources. Bacterial genera included Staphlyococcus, Pseudomonas, and Streptococcus, all of which have proinflammatory and pathogenic capacity. Our results suggest that the size distribution of bioaerosols emitted by dairy operations extends well above 10 μm in diameter and contains a diverse mixture of potentially hazardous constituents and opportunistic pathogens. These findings should inform the development of more effective emissions control strategies.