Adrenal ascorbic acid depletion as an index of preslaughter stress in pigs.

The weight of the adrenal glands and the amount of ascorbic acid they contained were measured in Large White pigs subjected to various preslaughter treatments. Compared with transport for four hours preslaughter, one hour's transport resulted in adrenal glands which weighed less and which contained less ascorbic acid. Pigs mixed with strange pigs in lairage had heavier adrenals containing more ascorbic acid than those of unmixed pigs. Increasing lairage time up to twenty-four hours raised both the concentration and total amounts of ascorbic acid in the adrenal glands. The results suggest that the depletion of ascorbic acid from the adrenal glands can be used as a measure of the stress experienced by animals during the preslaughter period and the extent to which resting in lairage allows them to recover.