Welfare During Slaughter without stunning (Kosher or Halal) differences between Sheep and Cattle
by Temple Grandin
Department of Animal Science
Colorado State University
Updated September 2012
Slaughter without stunning is controversial from an animal welfare standpoint. When this subject is being discussed it is essential to consider species differences between cattle and sheep. Welfare issues are greater for cattle because they take longer to become unconscious compared to sheep. When both carotid arteries are severed, sheep will lose sensibility within 2 to 14 seconds (Newhook and Blackmore 1982, Gregory and Wotton 1984, Nangeroni and Kennett 1963, Schulz et al 1978, Blackmore 1984). Most sheep will be insensible within 10 seconds. Calves and cattle take a longer period of time to become insensible and they are more likely to have a prolonged period of insensibility. The time to loss of insensibility when good cutting technique is used will range from 17 sec to 85 sec (Blackmore 1984, Blackmore et al 1983l, Gregory and Wotton, 1984, Grandin 2010, Daly et al 1988, Gregory et al 2010). Some cattle may have prolonged periods of sensibility lasting up to 385 seconds (Blackmore, 1984). When good technique is used the average time to collapse is 17 seconds (Grandin 2910). Both scientific research and practical experience indicate that cattle have more problelms with prolonged periods of sensibility compared to sheep. Another problem in cattle is occlusion of the carotids which can occur after the act (Gregory 2010). This problem is less likely to occur in sheep and goats. Occlusions caused by false aneuryms do not occur in sheep and goats (N. Gregory, Personal Communication in 2011).
The main reason for the differences between cattle and sheep is due to differences in the anatomy of the blood vessels that supply the brain (Baldwin and Bell, 1963 a,b,c; and Blackman et al, 1986). When slaughter without stunning is done, both carotid arteries are cut. In sheep the carotid arteriees that are located in the front of the throat provide the brain with it's entire supply of blood. In cattle the vertebral arteries which are not severed by the cut also supply the brain with blood. Therefore, when the carotids are severed in cattle the brain still has a blood supply. The differences in the blood supply to the brain of sheep and catle have been researched in detail (Baldwin and Bell 1963 a,b,c,d). It is also likley that the yak is similar to cattle (Ding et al 2007).
Some sheep die more quickly and are less likely to have extended periods of insensibility and should not be lumped together with cattle when welfare without stunning is being discussed. Sheep also do not require expensive, complicated restraint equipment. A lamb can be easily straddled by a person while standing in an upright position and cut. It is likely that a lamb slaughtered on the farm with a very sharp knife may have better welfare than a lamb that has to be subjected to the stress of being transported. A very sharp knife is essential. To test the knife it should be able to slice a standard A4 printer paper that is held dangling by one corner. The knife must be dry for this test. To help prevent pain the wound must be held opend during the act and the knife must be long enough so that it's tip remains outside the neck during the cut. The best cutting method is a Kosher or Halal cut that severs both carotid areteris. In situations where the loss of posture cannot be observed, a fixed fully dilated pupil can be used to determine complete loss of sensibility. When sheep are cut correctly, a fixed fully dilated pupil will occur in 20 seconds (Miriam Parker, Personal Communication in 2011). In sheep the wound should be held open during bleed out to facilitate bleed out. Cutting cattle close to the jawbone in the C1 position will help prevent false aneuryms and improve bleed out compared to the C2 to C4 position (Gregory et al, 2011).
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