VEHICLE MOTION AND MOTION SICKNESS IN PIGS

Low frequency oscillatory motion (0.05 to 0.5 Hz) experienced in ships and road vehicles is known to cause motion I sickness in humans and s ome predictive models are available. There have been very few studies of the evidence of motion sickness in rigs and none which has attempte d to identify the frequencies of motion of transporters which are like ly to be implicated. In this study, the vibration and motion character istics of a commercial pig transporter were measured while seven indiv idually penned 40-kg pigs were transported for short (100 min) journey s and 80-kg pigs penned in groups of 12 or 13 were transported for lon ger (4.5 h) journeys. Direct behavioural observations were made of ind ividual pigs for symptoms of travel sickness (sniffing, foaming at the mouth, chomping, and retching or vomiting). A comparison was then mad e between the incidence of travel sickness in rigs and that expected i n humans given the measured vehicle vibration characteristics. The low frequencies of motion measured on the transporter (0.01 to 0.2 Hz) we re well within the range implicated in human motion sickness with cons iderable pourer in the longitudinal and lateral axes but little in the vertical axis. On both short and long journeys pigs exhibited symptom s of travel sickness. The likely incidence of travel sickness on the s hout journeys predicted by the human model was 24 to 31% which corresp onds to approximately two of the seven 40-kg pigs becoming travel sick . The numbers observed were generally lower than this although the sam e pigs were transported twice each day for 2 days and this may have th erefore reflected the effects of habituation. The incidence of travel sickness on the long journeys predicted by the human model was 34%. Du ring these journeys which involved four groups of 80-kg pigs which wer e not repeatedly transported, 26% of pigs vomited or retched (13 out o f 50) while 50% showed advanced symptoms of foaming and chomping. Thes e results are not inconsistent with the human model which should form the basis further research.