The effect of shot biopsy on behavior, salivary cortisol, and heart rate in slaughter pigs.

This paper describes behavioral and physiological responses of pigs to shot biopsy, an experimental method used to study muscle tissue processes or to predict meat quality. One biopsy sample from the longissimus muscle was obtained from 23-wk-old gilts (n = 10) using a cannula connected to a captive bolt. Ten other gilts were used as a control and received a sham shot. One week later, a second biopsy was taken from the same gilts. Behavioral and salivary cortisol responses to both biopsies were similar (P > .10). Pigs flinched in response to the biopsies. Salivary cortisol concentrations were increased (P < .05) 15 min after the biopsy as compared with pretreatment levels, but absolute levels were not different (P > .10) from the control group. In both biopsy and control groups, heart rate increased (P < .001) in response to the presence of the technician. In response to the first biopsy, heart rate increased (P < .01) as compared with the rate during the 5-s period before the biopsy, but heart rate did not increase in response to the second biopsy. The biopsy pigs showed a decrease (P < .05) in initiating contact with the technician in the second test. We conclude that shot biopsy had a significant acute effect on behavior and heart rate. Therefore, the usefulness of this technique in studies in which the behavioral and heart rate responses are measured is limited.