Human subjective response to lorry vibration: Implications for farm animal transport

Abstract

Lorry drivers are exposed to a wide range of mechanical vibrations and random motions. The seat and sometimes the cab suspensions are designed to reduce vibration exposure. Nevertheless drivers are often subjected to considerable discomfort occurring within minutes of starting a journey. The frequencies and axes of vibration which occur at a driver's seat are often close to those of maximum discomfort for the human. On a livestock transporter, the interfaces between the animals and the vehicle are not designed to reduce vibration and it is possible that animals are subjected to a higher vibration magnitude than the driver. However, nothing is known of the discomfort or welfare levels experienced by livestock (e.g. cattle, sheep, pigs and poultry) during transport as the result of vibration and motion. This paper draws analogues with subjective evaluations of human comfort and poses a number of questions which must be addressed by research in order to quantify vibration dose, animal welfare response relationships. The primary requirement is to determine to what extent frequency dependent response weightings for the most important axes of vibration are necessary for each animal species and to determine how they should be defined. This would enable a comparison to be made between the experiences of humans and animals.