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 sho t biopsy, an experimental method used to study muscle tissue processes or t o:predict meat quality. One biopsy sample from the longissimus muscle was o btained from 23-wk-old gilts (n = 10) using a cannula connected to a captiv e bolt. Ten other gilts were used as a control and received a sham shot. On e 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 g roup; In both biopsy and control groups, heart rate increased ( P < .001) i n response to the presence of the technician. In response to the first biop sy, 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 th e second biopsy. The biopsy pigs showed a decrease (P < .05) in initiating contact with the technician in the second test. We conclude that shot biops y 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.