Full shift arm inclinometry among dairy parlor workers: A feasibility study in a challenging work environment David I. Douphrate a, * , Nathan B. Fethke b , Matthew W. Nonnenmann b, c , John C. Rosecrance d , Stephen J. Reynolds d a Division of Epidemiology, Human Genetics and Environmental Sciences, University of Texas School of Public Health, San Antonio Regional Campus, 7411 John Smith Drive, Suite 1100, San Antonio, TX 78229, USA b Occupational and Environmental Health, University of Iowa, USA c University of Texas Health Science Center at Tyler, TX, USA d Environmental and Radiological Health Sciences, Colorado State University, CO, USA article info Article history: Received 23 March 2011 Accepted 12 September 2011 Keywords: Work-related musculoskeletal disorders Exposure assessment Agriculture abstract Over the last 20 years, the US dairy industry has experienced a significant transformation from small farm operations to an industrialization of the milking process. This transformation has resulted in improvements in process efficiency and product quality. Milking tasks in large-herd parlors are highly- repetitive involving awkward postures and high muscle loads of the upper extremity. Field-based direct measures of physical exposures have been limited in challenging work settings such as dairies. This study evaluated full-shift exposures of posture and motion of the upper extremity among large-herd parlor milkers using wireless inclinometry. Results suggest large-herd parlor workers may be exposed to high exposure levels (posture, movement velocity, repetition, and inadequate rest) associated with the development of shoulder pathology. Compared to other high-risk occupations involving shoulder- intensive work, parlor workers may have higher exposure levels. These findings warrant the need for continued field-based research with larger sample sizes to facilitate the development of cost-effective intervention strategies. Ó 2011 Elsevier Ltd and The Ergonomics Society. All rights reserved. 1. Introduction 1.1. Industry profile and trends Over the past two decades, the US dairy industry has trans- formed into an efficient and quality driven work process in response to higher consumer demands. From 1989 through 2009, the number of US milking operations decreased by 68%, while during the same period milk production increased by 32%. Increased milk production despite a decreased number of dairy farms has been accomplished through increased milking herd sizes. The number of small herd operations (<500 head) continues to diminish whereas the number of large herd (500 head) opera- tions continue to rise (Douphrate et al., 2009). In 1998, nearly 70% of milk produced in the US came from small herd operations. By 2009, over 60% of milk produced in the US came from large herd operations, and 31% came from operations of 2000 head or more (NASS, 2010). Limited research has addressed worker health and safety in these mass-production milking environments, and addi- tional injury research is needed given the trend to large herd dairy farms (Douphrate et al., 2009). 1.2. Parlor operations Two types of milking systems are used on US dairy farms: The stanchion (tethered) system and the parlor (loose-housing) system. In stanchion systems, milking units are brought to the tethered dairy cow. In contrast, parlor systems involve cows freely moving into stationary milking stalls where they are milked simultaneously. After milking, cows exit and a new group enters the parlor to begin the milking process. Milking parlors can accommodate large numbers of cows and, consequently, the parlor system is used almost exclusively in large herd operations. In 2006, 78% of US dairy cows were milked in a parlor compared to 54.9% in 1996. In 2006, 100% of large herd dairy operations used a milking parlor (USDA, 2007). Milking parlor configurations are defined by the orientation of the cow in relation to each other and in relation to the worker. The cow’s orientation affects udder accessibility and may have * Corresponding author. Tel.: þ1 210 562 5505; fax: þ1 210 562 5528. E-mail address: david.i.douphrate@uth.tmc.edu (D.I. Douphrate). Contents lists available at SciVerse ScienceDirect Applied Ergonomics journal homepage: www.elsevier.com/locate/apergo 0003-6870/$ e see front matter Ó 2011 Elsevier Ltd and The Ergonomics Society. All rights reserved. doi:10.1016/j.apergo.2011.09.007 Applied Ergonomics 43 (2012) 604e613