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 legislation and meets the 'higher standard' ventilation requirement for vehicles which are to be used to transport animals for over 8 h.

Extraction fans are located at regions of low external pressure on the moving vehicle to optimize performance in transit and provide a controlled variable throughput of air. The system provides air movement over all the animals and is independent of vehicle movement.

The design of this prototype system has enabled detailed measurements of heat and moisture production of the animals. Preliminary assessment of the system has been effected during two commercial journeys moving pigs from farms to an abattoir. The variability in heat loss from the animals ranged between 1.4 and 1.9 W kg(-1) liveweight but in both cases the split between sensible (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 development of improved forced ventilation systems. Such systems will be an essential component in vehicles which are being designed to improve animal welfare in transit. (C) 2001 Silsoe Research Institute.