WELFARE OF CALVES .2. INCREASE IN VERTEBRAL ARTERY BLOOD-FLOW FOLLOWING EXSANGUINATION BY NECK STICKING AND EVALUATION OF CHEST STICKING ASAN ALTERNATIVE SLAUGHTER METHOD

The role of the vertebral arteries in delaying loss of sensibility fol lowing neck sticking in slaughter calves was investigated. Vertebral a rtery blood flow was measured using probes before, during and after el ectrical stunning and slaughter. Systemic blood pressure, electrocorti cogram, visually evoked responses and the occurrence of carotid occlus ions were also recorded. When carotid occlusion occurred, the time to onset of brain failure was delayed based on the development of an isoe lectric state. In addition, when carotid occlusion occurred the mean a rterial blood pressure was sustained for longer following slaughter, a nd concurrently vertebral artery bload flow could be maintained at abo ut 30% of its initial level for up to 3 min. In some animals vertebral artery flow increased substantial following sticking. When chest stic king was used no occlusion of vessels occurred mean arterial blood pre ssure fell promptly (within 8 s) and the onset of an isoelectric state did not extend beyond one minute. In addition, visually evoked respon ses were not present after 5 s following chest sticking.