Effect of the duration of road transport on the physiology and meat quality of lambs

To assess the effect of transport duration on animal welfare and meat quality of lambs, two trials were performed: Forty Ile-de-France x Merino lambs were used in Trial 1 and 40 Comisana lambs in Trial 2. In both trials, the lambs, aged between 14 and 16 weeks, were divided into two groups of 20 animals. One group was subjected to a 1-h period of transportation (T1) and the other to a 24-h period of transportation (T24), both in the same truck and arriving to the same slaughterhouse at the same time. The effect of transport on serum biochemistry variables (cortisol, aspartate transaminase, lactate dehydrogenase, blood urea nitrogen, creatine kinase, creatinine and total proteins), salivary cortisol, metabolites of cortisol in faeces, intra-ruminal temperature and meat quality (pH, conductivity, expressible juice, colour and shear force) was assessed. In both studies, the duration of transport did not affect serum and salivary cortisol concentration (P > 0.05). However, in Trial 2, lambs exposed to 24-h transport had a higher concentration of faecal cortisol metabolites than did those transported for 1 h (P < 0.05). Blood variables were not affected by transport in either trial (P > 0.05), with the exception of blood urea nitrogen which was higher in Trial 1 for the T24 group (P < 0.05) than it was to T1 group. Although no signs of dehydration were found, intra-ruminal loggers showed that animals did not drink during the transportation in the way they did before transport. In Trial 1, no effect of transport duration was found on meat-quality traits (P > 0.05). Nevertheless, in Trial 2, lambs exposed to 24-h transport had higher values of colour attribute of a* (red trend) and less tenderness or higher values of shear force (P < 0.05). The present study showed that although there is little effect on meat quality, signs of stress are detectable in lambs transported for 24 h. Therefore, in the case of lambs, the effect of long transportation periods must be considered more in terms of animal welfare than in terms of product quality.