Differences in blood supply to the cerebral cortex between sheep and calves during slaughter

Blackman, N.; Cheetham, K; Blackmore, D.K.

doi:10.1016/s0034-5288(18)30522-8

Cited by 21 publications

(6 citation statements)

References 5 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…The shorter durations observed here may be due to the physiological trauma being caused as a result of the killing methods. For example, damage to the brain stem (site of pupillary and nictitating membrane reflex control) can suppress blood supply to the eye [34], therefore affecting their responses. The short-acting sevoflurane anesthetic does not appear to have affected the durations adversely, since previously this anesthetic prolonged the cessation of such reflexes when birds were deeply anaesthetized [19].…”

Section: Discussionmentioning

confidence: 99%

Welfare assessment of novel on-farm killing methods for poultry

Martin

Sandilands

Sparrey³

et al. 2019

PLoS ONE

View full text Add to dashboard Cite

There is a need for novel mechanical devices for dispatching poultry on farm following the introduction of EU Regulation (EC) no. 1099/2009 On the Protection of Animals at the Time of Killing. We examined three novel mechanical killing devices: Modified Armadillo, Modified Rabbit Zinger, a novel mechanical cervical dislocation device; and traditional manual cervical dislocation. The four killing methods were tested on 230 chickens across four batches. We measured behavioural, electroencephalogram and post-mortem outcomes in anesthetized laying hens and broilers at two life stages (juveniles and adults/slaughter age). Graeco Latin-Square designs systematically randomized killing treatment, bird type, age and kill order. All birds were lightly anaesthetized immediately prior to the killing treatment with inhalation of Sevoflurane. The novel mechanical cervical dislocation method had the highest kill success rate (single application attempt only, with no signs of recovery) of a mechanical method (96%). The Modified Armadillo was the least reliable with 49% kill success. Spectral analysis of electroencephalogram signals at 2 s intervals for successfully killed birds only revealed progressive decreases in median frequency alongside increases in total power. Later, total power decreased as the birds exhibited isoelectric electroencephalogram signal. Latencies to pre-defined spectral ranges associated with unconsciousness showed that birds subjected to manual and novel mechanical cervical dislocation achieved these states sooner than birds subjected to the modified Armadillo. Nevertheless all methods exhibited short latencies (<4 s). The Modified Rabbit Zinger had the shortest duration of reflex persistence for nictitating membrane, pupillary and rhythmic breathing post method application. Of the methods tested, the novel mechanical cervical dislocation device is the most promising mechanical method for killing poultry on-farm based on a range of behavioural, electroencephalogram and anatomical parameters. This device has the potential to fulfil the current need for a mechanical alternative to manual cervical dislocation.

show abstract

Section: Discussionmentioning

confidence: 99%

Welfare assessment of novel on-farm killing methods for poultry

Martin

Sandilands

Sparrey³

et al. 2019

PLoS ONE

View full text Add to dashboard Cite

show abstract

“…The integration centre is located in the midbrain, near the reticular formation. This reflex may be less adapted after the start of bleeding because the blood loss can reduce the functioning of the retina (Blackman, Cheetham, & Blackmore, 1986). Blood covering the cornea may also reduce the feasibility of the test.…”

Section: Absence Of Eye Reflexesmentioning

confidence: 99%

Consciousness, unconsciousness and death in the context of slaughter. Part II. Evaluation methods

Terlouw

Bourguet²,

Deiss

2016

Meat Science

View full text Add to dashboard Cite

This second review describes indicators of consciousness and unconsciousness that can be used in the abattoir. These indicators evaluate different aspects of cerebral functioning, but only indirectly. It is therefore necessary to monitor several indicators. Animals are considered unconscious if signs of consciousness are absent, and signs of unconsciousness are present. Given that the unconscious state may be reversible it is further necessary to monitor these indicators until the end of bleeding. The techniques used to diagnose brain death in humans cannot be used in the slaughterhouse. Under field conditions, at the end of bleeding, the absence of breathing and of brainstem reflexes and the adequacy of the exsanguination are verified. If these three aspects are confirmed, in the context of the slaughterhouse and at this stage of the slaughter process the loss of vital functions is irreversible and the animal can be considered dead.

show abstract

“…The pupillary light reflex is tested by letting light fall on the eye and observing whether the pupil adapts to it. The reflex is controlled by cranial nerves II (optic) and III (oculomotor) and is not considered a reliable reflex during exsanguination, as exsanguination interferes with the blood supply to the retina (Blackman et al , 1986 ). When testing the threat reflex, an object (finger or pencil) suddenly approaches the eye and a conscious animal will close its eye or withdraw the head.…”

Section: Assessing Unconsciousnessmentioning

confidence: 99%

Indicators used in livestock to assess unconsciousness after stunning: a review

Verhoeven

Gerritzen

Hellebrekers

et al. 2015

Animal

View full text Add to dashboard Cite

Assessing unconsciousness is important to safeguard animal welfare shortly after stunning at the slaughter plant. Indicators that can be visually evaluated are most often used when assessing unconsciousness, as they can be easily applied in slaughter plants. These indicators include reflexes originating from the brain stem (e.g. eye reflexes) or from the spinal cord (e.g. pedal reflex) and behavioural indicators such as loss of posture, vocalisations and rhythmic breathing. When physically stunning an animal, for example, captive bolt, most important indicators looked at are posture, righting reflex, rhythmic breathing and the corneal or palpebral reflex that should all be absent if the animal is unconscious. Spinal reflexes are difficult as a measure of unconsciousness with this type of stunning, as they may occur more vigorous. For stunning methods that do not physically destroy the brain, for example, electrical and gas stunning, most important indicators looked at are posture, righting reflex, natural blinking response, rhythmic breathing, vocalisations and focused eye movement that should all be absent if the animal is unconscious. Brain stem reflexes such as the cornea reflex are difficult as measures of unconsciousness in electrically stunned animals, as they may reflect residual brain stem activity and not necessarily consciousness. Under commercial conditions, none of the indicators mentioned above should be used as a single indicator to determine unconsciousness after stunning. Multiple indicators should be used to determine unconsciousness and sufficient time should be left for the animal to die following exsanguination before starting invasive dressing procedures such as scalding or skinning. The recording and subsequent assessment of brain activity, as presented in an electroencephalogram (EEG), is considered the most objective way to assess unconsciousness compared with reflexes and behavioural indicators, but is only applied in experimental set-ups. Studies performed in an experimental set-up have often looked at either the EEG or reflexes and behavioural indicators and there is a scarcity of studies that correlate these different readout parameters. It is recommended to study these correlations in more detail to investigate the validity of reflexes and behavioural indicators and to accurately determine the point in time at which the animal loses consciousness.

show abstract

Differences in blood supply to the cerebral cortex between sheep and calves during slaughter

Cited by 21 publications

References 5 publications

Welfare assessment of novel on-farm killing methods for poultry

Welfare assessment of novel on-farm killing methods for poultry

Consciousness, unconsciousness and death in the context of slaughter. Part II. Evaluation methods

Indicators used in livestock to assess unconsciousness after stunning: a review

Contact Info

Product

Resources

About