THE WELFARE OF SLAUGHTER PIGS DURING TRANSPORT

The welfare of transported pigs can be compromised both by physical an d psychological stresses. The animals' responses can be assessed using records of mortality and trauma, physiological and behavioural observ ations and, to some degree, by measurements of meat quality since this can reflect the animals 'physiological state at death. These assessme nts may, therefore, be used as measures of animal welfare. During tran sport pigs show weight loss, increased circulating concentrations of c atecholamines, cortisol and creatine phosphokinase (CPK), and an incre ase in heart rate and packed cell volume; sometimes there is evidence of dehydration. Increased levels of dark, firm, dry (DFD)meat after lo ng transport reflect muscle glycogen depletion and possibly indicate s ome element of fatigue. There is experimental evidence that transport is aversive to pigs, which may be partially due to the fact that they become travel sick. Mortality in transport has ranged from < 0.1 to > 1.0 per cent in different European countries. Mortality is higher in m ore stress-susceptible breeds and at higher ambient temperatures. It i s increased in pigs fed within 4h of transport, at higher stocking den sities and after longer journeys at ambient temperatures greater than 10 degrees C. Pigs may be fasted long enough before slaughter to preju dice their welfare through hunger. Long fasts may also reduce muscle g lycogen levels and cause fatigue. Fighting between unfamiliar animals which have been mixed during the marketing procedure is also stressful , however, longer transport may actually reduce this problem by allowi ng animals to get used to one another under conditions in which it is difficult to fight.