Effects of deck height during transport of weaners::in-vehicle conditions and clinical indicators

We aimed to examine if deck height affected in-vehicle conditions (temperature and CO2 concentration as indicators of ventilation) when weaners are transported at stocking densities corresponding to EU-regulation, and to examine consequences in terms of mortality, weight loss, and post-transport skin lesions for pigs at 20-25 kg. We performed two field trials consisting of 32 semi-controlled journeys under conditions modelling commercial Danish practice; half of 8 and 23 h, respectively, run in warmer and colder periods from June 2021 to March 2022. Deck heights of 60 vs 80 cm (trailer) and 70 vs 90 cm (truck) were compared. We collected a mixture of sensor time series, GPS records, weather data from a public online source, clinical examination of focal animals, and various information on settings like opening of ventilation shutters and animal stocking density. Data were analysed by (generalised) linear mixed effects models. Lower deck height had only sporadic and minor effects on the indicators examined. Horizontal differences in temperature and CO2 concentration were detected among vehicle compartments. In the colder period, large differences were found between study sensors placed close to the pigs and embedded temperature sensors placed in the outer wall of the vehicle. Thus, the livestock driver may be misinformed by information from embedded sensors and left with limited chances of adjusting conditions; being examined further by a follow-up study.