Use of 'thoracic stick' in halal slaughter of bobby calves.
Throat cutting associated with halal slaughter of bobby calves fails to sever the vertebral arteries supplying the brain. Such slaughter may be inhumane due to calves recovering from the stun before permanent insensibility, due to blood loss, occurs. Interruption of the vertebral arteries may be achieved by severance of the brachiocephalic trunk or penetration of the heart by the use of a 'thoracic stick', an incision with a knife through the thoracic inlet.
Welfare of calves - 2. Increase in vertebral artery blood flow following exsanguination by neck sticking and evaluation of chest sticking as an alternative slaughter method.
The role of the vertebral arteries in delaying loss of sensibility following neck sticking in slaughter calves was investigated. Vertebral artery blood flow was measured using probes before, during and after electrical stunning and slaughter. Systemic blood pressure, electrocorticogram, visually evoked responses and the occurrence of carotid occlusions were also recorded. When carotid occlusion occurred, the time to onset of brain failure was delayed based on the development of an isoelectric state. In addition, when carotid occlusion occurred the mean arterial blood pressure was sustained for longer following slaughter, and concurrently vertebral artery blood flow could be maintained at about 30% of its initial level for up to 3 min. In some animals vertebral artery flow increased substantially following sticking. When chest sticking was used no occlusion of vessels occurred, mean arterial blood pressure fell promptly (within 8 s) and the onset of an isoelectric state did not extend beyond one minute. In addition, visually evoked responses were not present after 5 s following chest sticking.
Non-penetrative percussion stunning of sheep and calves
Attempts were made to stun lambs, adult sheep and calves by a non-penetrative percussive method. Using an adapted Cash pistol, with a concave padded impact head, impulses were produced which effectively stunned 96% of lambs but induced brain haemorrhages in up to 7% of the animals. The signs and duration of an effective percussive stun were observed and recorded. Calves were readily stunned by percussive methods but brain haemorrhages frequently occurred. Impulses sufficiently large to stun adult sheep, with a non-penetrating impact head, were produced from an adapted Hantover pneumatic cattle stunner. Comparative trials, using electrical and percussive stunners, demonstrated a significant decrease in the prevalence of blood splash in lambs stunned by percussion.