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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. [ABSTRACT FROM AUTHOR]

The effect of slaughter at arrival (L0) or after 3 (L3), 6 (L6), 12 (L12) h of lairage on carcass and meat quality of suckling lambs has been studied. Lairage time had a slight effect on carcass quality traits, but most of the meat quality parameters at 24h post mortem were affected. Weight losses increased and glycogen content of liver and longissimus muscle decreased as lairage time increased. Longissimus muscle from L3 lambs had the highest pH, shear force and toughness and the lowest b* and C* values, at 24h post mortem. L3 and L6 had the higher proportion of expelled juice, or low water holding capacity (WHC), at 24h post mortem. Texture parameters and WHC were similar among groups after 5 days of storage. Despite the fact that the effects of lairage time on meat quality disappears after storage, from the point of view of weight losses the slaughter of suckling lambs at arrival is recommended., (© 2013.)