Updated February 2012
Two major welfare problems can occur during slaughter without stunning. They are a prolonged period where the bovine remains sensible and aspiration of blood into the trachea (windpipe) and respiratory tract. Blood entering the respiratory tract is a welfare concern because the sensation caused by blood entering the respiratory system is likely to be very distressful. Observations and research done by Neville Gregory and other researchers indicates that cutting cattle close to the jawbone will eliminate the transmission of "potentially unpleasant sensory signals associated with blood contaminating the upper and lower respiratory tract" (Gregory et al, 2011). When the cut is made close to the jawbone in the C1 (Cervical 1) position, the sensory nerve to the respiratory tract is severed. Most Halal and Kosher cuts are made further away from the jaw in the C2 to C4 position (Gregory et al, 2011). In this position, the sensory nerve remains in tact and distressful sensations could be transmitted to the brain before the animal loses sensibility.
Cutting in the C1 position close to the jaw will also help prevent prolonged periods of sensibility caused by sealing off of the artery ends. Gregory et al (2011) have also reported that approximately 3 to 5% of the cattle have delayed onset of insensibility. This is similar to observations I have made in plants that have expert Kosher slaughter. Most cattle that have delayed onset of insensibility will have occluded arteries caused by false aneurysms. Cutting close to the jawbone in the C1 position greatly reduces the formation of false aneurysms. When cattle were cut in the C1 position, only 1% of the arteries were occluded. When they were cut in the C3 position, which is further away from the jaw, one-third of the cattle had false aneurysms. Switching the position of the cut to the C1 position has the potential to greatly improve animal welfare. Some Halal slaughter is already being performed by cutting close to the jawbone. In Halal, cutting in the C1 position is strongly recommended. For Kosher slaughter, the knife is not permitted to touch the jawbone. Research is needed to determine if Kosher cuts that are ritually correct will reliably sever the nerve to prevent distressful sensations from aspirated blood from being perceived by the cattle. Gregory et al (2011) concluded "changing to a cut a C1 could partly reduce the potential for suffering during slaughter without stunning."
In a slaughter plant with an upright restraint box, kosher slaughter in the C1 position was tested on three large beef steers. The cattle were brought quietly into the box with no electric prods. All three animals remained silent and did not vocalize (moo or bellow) in response to being restrained. They were cut immediately after the head was positioned and after the cut the pusher gate, belly lift, and head restraint were released. On one animal the procedures worked perfectly and the animal collapsed and lost the ability to stand within 15 seconds. The other two had prolonged sensibility of over a minute.
Future things to try include experimenting with the angle of the cut so that the knife is oriented towards C1 and the larynx remains with the head and contact with the jawbone is avoided. When the larynx remains with the head, the groaning sounds will be eliminated. Another variable is bending of the neck and tightness of the head holder. The animal that was relaxed and not held tightly was the animal that lost the ability to stand within 15 seconds.
Gregory, N.G., Schuster, P., Mirabito, L., Kolesar, R., and McManus, T. 2011. Arrested blood flow during false aneurysm formation in the carotid arteries of cattle slaughtered with and without stunning. Meat Science, Volume 90, Issue 2, February 2012, Pages 368-372.
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