Effects of lavender straw on stress and travel sickness in pigs.
OBJECTIVE: To observe pigs during road journeys in order to establish whether lavender straw was likely to decrease stress and incidence of travel sickness. SUBJECTS: Forty 70-kg Large White pigs were transported by road for 2 hours, 20 animals each day, over a 2-day period. DESIGN: On day 1, ample wheat straw was provided as bedding such that the floor of the vehicle was entirely covered (straw condition). On day 2, lavender straw was provided as bedding (lavender condition). During the journey, direct behavioral observations of the individually marked pigs were made by scanning every 10 minutes for incidence of standing and lying along with the less severe symptoms of travel sickness (foaming at the mouth and repetitive chomping). Incidences of retching and vomiting were noted as they occurred. A general activity index was also scored every 10 minutes (5 = high activity, 1 = low activity). Saliva samples were taken from each animal at different stages of the journey for analysis of cortisol. RESULTS: Pigs stood more when in the straw condition, but were more active when standing in the lavender condition. Symptoms of travel sickness appeared to be less acute in the lavender condition, with more animals exhibiting the less severe symptom, foaming and chomping (a total of 3 in straw compared with 6 in lavender), but fewer animals showing the more severe symptoms of retching and vomiting (in straw, 3 retched, 6 vomited; in lavender 0 retched, 3 vomited). A total of 6 animals retched or vomited in the straw condition but only 3 in the lavender. There was a significant difference in mean concentrations of cortisol between conditions but this was due to a difference in mean baseline concentrations between groups. CONCLUSION: Addition of lavender straw appeared to decrease incidence and severity of travel sickness but not overall levels of stress (as measured by concentrations of salivary cortisol).