Welfare During Slaughter without stunning (Kosher or Halal) differences between Sheep and Cattle

by Temple Grandin
Department of Animal Science
Colorado State University

Updated October 2019

There have been many recent reports from veterinarians and welfare auditors that halal or kosher unstunned slaughter is being done poorly in many countries. This has resulted in animals remaining conscious for several minutes. This quick loss of consciousness described below will not occur if procedures are done poorly. If the animal does not lose consciousness within 30 seconds, it should be immediately stunned with a captive bolt. A better alternative for abattoirs that have poor management would be pre-slaughter stunning. This information in my articles must never be used as a way to cover up a sloppy operation.

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). A veterinarian working in the slaught plants observed that using a hot knife direct from the sterilizer may cause occlusions.

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 cattle 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).

Overall Welfare

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). There is controversy concerning the painfulness of the cut (Gibson et al, 2015). When the cut is performed by a knife that is sharpened on a grind stone, it was a definately painful in calves (Gibson et al, 2009 a,b). It is possible that the knifed used in this study was too short. This may have caused the tip to gouge the throat.

References

Baldwin, B.A. and Bell, F.R. 1963. The effect of temporary reduction in cephalic blood flow on the EEG of sheep and calf. Electroencephalography and Clincal Neurophysiology. 15:465-473.

Baldwin, B.A. and Bell, F.R. 1963. The anatomy of the cerberal circulation of the sheep and ox; The dynmaic distribution of hte blood supplied by the carotid and vertebral arteries to cranial regions. J. Anatomy Lund. 97:203-215.

Baldwin, B.A. and Bell, F.R. 1963. The rate of blood flow in the vertical is greater than in sheep. Journal of Physiology, 167.

Blackman, N., Cheetham, K., and Blackmore, D.K. 1986. Differences in blood supply to the cerebral cortex between sheep and calves. Research in Veterminary Science. 40:252-254.

Blackmore, D.K. 1984. Differences in behavior between sheep and cattle during slaugher. Researh in Veterinary Science. 37:223-226.

Daly, C.C., Kallweit, and Ellendorf (1988). Cortical functional in cattle during slaguther. Veterinary Record. 122:325-329.

Ding, Y., Shao, B., an Wing, T. (2007) The arterial supply to the brain of tu Yak (Bos grunniens). Ann. Anatomy. 189:31-38.

Gibson, T.J., Johnson, C.B., Murrell, J.C., Hulls, C.M., Mitchinson, S.L., et al (2009a). Electroencephalographic responses of halothane-anesthetized calves to slaughter by ventral-neck incision without stunning. N.Z. Vet., J. 57:77-85.

Gibson, T.J., Johnson, C.B., Murrell, J.C., Chapters, J.P., Stafford, K.J. and Mellor, D.J. (2009b). Components of electroencephalographic responses to slaughter in halothane-anesthetized calves. N.Z. Vet., J. 57:84-89.

Gibson, T.J., Dadios, N., and Gregory, N.G. (2015). Effect of neck cut position on time to collapse in halal slaughtered cattle without stunning. Meat Science. 110, 310-314.

Grandin, T. (2010). Auditing animal welfare at slaughter plants. Meat Science. 86:56-65.

Gregory, N.G., von Wenzlawowicz, M., von Hollenben, K., Fielding, H.R., Gibson, T.J., Mirabito, L., and Kolesar, R. (2010). Complications during halal slaughter or shechita in cattle. Humane Slaughter Association Centenary International Symposium, Portsmouth, UK.

Gregory, N.G. et al (2010). Time to collapse following slaughter without stunning of cattle. Meat Science. 85:66-69.

Gregory, N.G., and Wotton, S.B. (1984). Time to loss of brain responsiveness following exsanguination in calves. Research in Anim. Veterinary Science. 37:141-143.

Nangeroni, L.I., and Kennet, P.D. (1983). An electroencephalographic study of the effects of shechita slaughter on cortical function is rummants. Report Ithaca University. Ithaca, NY.

Newhook, J.C. and Blackmore, D. K. 1982. Electroencephalographic studies of stunning and slaughter in sheep and calves Part 1 - The onset of permanent insensibility in sheep during slautgher. Meat Sciences. 6:295-300.

Schulz, W. et al. (1978). Deutche Tierarztliche Wochenschrift. 85:41-76.

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