Assessment and comparison of electrocardiographic and clinical cardiac evidence of death following use of a penetrating captive bolt for euthanasia of cattle

The objective of this study was to describe temporal associations between cardiac auscultation and ECG to evaluate cardiac activity and determine cardiac death following euthanasia with a penetrating captive bolt device. Twenty-two feedlot calves between 6 and 19 months of age were enrolled. Electrocardiographic monitoring and recording was conducted using a modified base-apex lead configuration. Cardiac death was defined as ventricular standstill and occurred when ventricular electrical activity ceased. Clinical cardiac death was defined as the absence of an auscultable and rhythmic heartbeat, and was assessed immediately following the final captive bolt administration and again at 1-minute intervals for a minimum of 10 minutes post-captive bolt administration. Discernable cardiac activity was demonstrated for an average of 513.35 seconds (8 minutes 34 seconds) post-captive bolt administration. Clinical cardiac death and ventricular standstill occurred within the same 60-second measurement in 33% (7/21) of calves. Thus, approximately 70% of calves were assumed to be deceased based on clinical cardiac parameters prior to ventricular standstill.