Abstract :
To evaluate the effect of stocking density and transport time on physiological responses and meat quality, 72 male suckling lambs
were transported by road to the slaughterhouse at three different stocking densities (0.12, 0.20 or 0.25m2/lamb) and two transport
times (5 h or 30 min). Blood samples were collected pre-transport at the farm and after unloading in the slaughterhouse to measure
levels of cortisol, creatine kinase (CK) and lactate dehydrogenase (LDH). After slaughter, the weights of the hot carcass, liver and
spleen were recorded and pH in Musculus longisimus thoracis et lumborum (L), Musculus semitendinosus (ST) and Musculus psoas
major (PM) were determined. Colour, water-holding capacity (WHC), texture and thiobarbituric acid-reactive substances (TBARS)
values were measured in samples of L, at 24 h post mortem and after 5 days of ageing. Cortisol and LDH were higher in suckling
lambs transported for 30 min than those transported for 5 h. Stocking density did not affect blood parameters studied. Transport
time significantly affected some carcass quality parameters, but stocking density had no significant effect. Suckling lambs
transported for 5 h had lower liver weights and dressing percentages than those transported for 30 min. Transport time influenced
pH values, with lambs subjected to the longer journey showing the lowest pH at 0 h in the three muscles studied, with the lowest
final pH in L and PM. The PM lambs transported at high density (0.12m2/lamb) had the lowest pH at 24 h. Transport time and
stocking density did not greatly affect colour and texture parameters. The meat from lambs transported for 30 min had higher WHC
than meat from lambs transported for 5 h. Animals transported for longer journeys showed higher lipid oxidation after 5 days of
ageing than those transported for 30 min. Loading and initial transport caused significant stress response in suckling lambs, that
stress response was reduced over the time course of the journey.
Keywords :
animal welfare , suckling lambs , meat quality , Stocking density , transport time