Transport of pigs different with respect to the halothane gene: stress assessment

Two transport experiments were carried out with 18 pigs each. These pigs originated from three genetic lines (homozygous halothane-positive and -negative and heterozygotes). Half the pigs were unfed for 12 h before transport. All pigs were transported twice for 2 h. Before and after transport pigs were anesthetized to take blood samples from the jugular vein and biopsies from the biceps femoris. At the same time equipment to measure body temperature and heart rate were attached or detached. Plasma cortisol and beta-endorphin concentrations were measured as well as the glycogen concentration in the muscle sample. Line differences were detected with respect to body temperature (P < .04), heart rate (P < .05), and cortisol (P < .01). The withholding of feed influenced (P < .04) plasma beta-endorphin concentration. Body temperature (P < .02), heart rate (P < .001), cortisol (P < .01), and beta-endorphin (P < .001) were different before and after transport, whereas a training effect of the transport number was observed for heart rate (P < .07) and plasma beta-endorphin (P < .02). No interactions between treatments were observed. The relationship between cortisol and beta-endorphin suggests a nonconcomitant release of ACTH and beta-endorphin.