Design and operation of a prototype mechanical ventilation system for livestock transport vehicles

A prototype, mechanically ventilated, livestock transport vehicle (for pigs , sheep or cattle) is described. The design complies with current legislati on and meets the 'higher standard' ventilation requirement for vehicles whi ch are to be used to transport animals for over 8 h. Extraction fans are located at regions of low external pressure on the movi ng vehicle to optimize performance in transit and provide a controlled vari able throughput of air. The system provides air movement over all the anima ls and is independent of vehicle movement. The design of this prototype system has enabled detailed measurements of he at and moisture production of the animals. Preliminary assessment of the sy stem has been effected during two commercial journeys moving pigs from farm s to an abattoir. The variability in heat loss from the animals ranged betw een 1.4 and 1.9 W kg(-1) liveweight but in both cases the split between sen sible (45%) and latent (65%) heat loss was comparable. These initial data, when augmented with further studies over a wider range of ambient conditions, can be used as the basis for guidelines for the deve lopment of improved forced ventilation systems. Such systems will be an ess ential component in vehicles which are being designed to improve animal wel fare in transit. (C) 2001 Silsoe Research Institute.