Effects of season and stocking density during transport on live weight and biochemical measurements of stress, dehydration and injury of rabbits at time of slaughter

The effects on rabbit welfare of transport in two seasons (summer and winter) and at two stocking densities (high stocking density : 12 rabbits per cage; low stocking density : 8 rabbits per cage) were studied. The loss of live weight during transport was calculated. At slaughter, blood samples were obtained and some physiological parameters related to stress were analysed : cortisol, creatine kinase (CK), lactate dehydrogenase (LDH), lactate, glucose, packed cell volume (PCV), osmolarity, and albumin and globulin concentrations. In addition, liver and muscle samples were taken and immediately frozen in liquid nitrogen for subsequent glycogen measurements. Season significantly affected the live-weight losses and plasma concentrations of cortisol (P < 0·01), CK, LDH, lactate (P < 0·001) and glucose (P < 0·01), as well as osmolarity (P < 0·001). Liver and muscle glycogen concentration were also affected by the season (P < 0·001). The loss of live weight was higher in rabbits transported in winter than in summer. The plasma concentrations of cortisol, lactate and glucose, CK and LDH activity, and osmolarity, as well as liver and muscle glycogen concentrations were higher in rabbits transported in summer than in winter. Stocking density had no effect on the analysed parameters. The high levels of the analysed blood parameters, which are related to stress, lead to the conclusion that the welfare of the rabbits transported in summer was more affected than those transported in winter.