Ergonomic Interventions Designed for Obtaining the Birth Weight of Calves

Abstract

In the agricultural industry, one area where farmers are exposed to occupational risk factors, such as heavy lifting and shoulder abduction, is in the beef cow industry where farmers are required to obtain the birth weight of a new born calf by lifting it off the ground. This current method puts farmers at a greater risk for developing musculoskeletal disorders such as low back or shoulder pain. The objective of this research was to develop and evaluate ergonomic interventions for weighing calves. Two ergonomic interventions – the “Handle Attachment” and the “Lever Arm” were designed to change the posture of the farmer and to move the internal muscle forces acting on the shoulder and back to the lower extremities. For the current method and both interventions, EMG data was collected for the right upper extremity, back, and leg muscles. Biomechanical models of the postures held during the current method and the two interventions were developed to determine the percent strength capability of the shoulder, shoulder moments, the spinal compression, and the L5/S1 moment. The results show that both interventions reduce the required muscle activity and the spinal compression while increasing the percent strength capability of the shoulder. Overall, the Handle Attachment is less cumbersome than the Lever Arm, but the Lever Arm provides the reduction in muscle activity and spinal compression. Using either intervention when weighing a calf should decrease the risk of low back pain and shoulder injuries.