Validation of the acute electroencephalographic responses of calves to noxious stimulus with scoop dehorning

Gibson, T. J.; Johnson, Craig B.; Stafford, K. J.; Mitchinson, Sheryl L; Mellor, D. J.

doi:10.1080/00480169.2007.36760

Cited by 88 publications

(85 citation statements)

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“…Significant increases in F50 and F95 were found during the first 10 s after decapitation. These are consistent with responses to noxious stimulation found in other studies 15,19,21,22 and can be interpreted as such. A significant and a gradual decrease in the Ptot was observed in the current study and was similar to the reductions in the power component of specific EEG frequency bands (1-100 Hz and 13-100 Hz) after decapitation of both conscious and anaesthetized rats reported in a recent study.…”

Section: Discussionsupporting

confidence: 81%

Electroencephalographic evaluation of decapitation of the anaesthetized rat

et al. 2013

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The objective of this study was to evaluate the changes in electroencephalographic (EEG) power spectrum in response to decapitation of anaesthetized rats, in order to assess the nociception or otherwise of this procedure. Ten young adult male Sprague-Dawley rats were anaesthetized with halothane in oxygen and anaesthesia was maintained at a stable concentration of halothane between 1.20% and 1.25%. The rat's head and neck were placed through the opening of a small animal guillotine so that the blade of the guillotine was positioned over the atlanto-occipial joint of the rat's neck. The EEG was recorded in a five-electrode montage, bilaterally. After recording a 15 min baseline the rat was decapitated by swiftly pressing the guillotine blade and the EEG recording was continued until the signal was isoelectric on both channels. Changes in the median frequency (F50), 95% spectral edge frequency (F95) and total power of the EEG (Ptot) were used to investigate the effects of decapitation. During the first 15 s following decapitation, there were significant increases in the F50 and F95, and a decrease in the Ptot compared with baseline values. There was a clear window of time immediately following decapitation where changes in the EEG frequency spectrum were obvious; these changes in the EEG indices of nociception could be attributed as responses generated by the rat's cerebral cortex following decapitation.Keywords rat, electroencephalogram, euthanasia, welfare, nociception Several different methods of euthanasia have been proposed for use in laboratory animals in biomedical research (e.g. injectable anaesthesia, decapitation, cervical dislocation, CO 2 asphyxiation, etc.). 1Decapitation has the advantage that it has no effect on subsequent analytical procedures.2 This is not the case with chemical methods such as a drug overdose. Despite its common use, the humaneness of decapitation of conscious animals is debatable.2-5 The question of whether brain activity continues after decapitation and, if so, for how long, has been considered essential for determining the acceptability of this procedure. These questions have been addressed in a number of studies involving different animal species including rats.2,6-10 Studies utilizing electroencephalographic (EEG) recordings have been used to map the brain following decapitation. Conversion from high voltage slow activity to low voltage fast activity (LVFA) and desynchronization, a shift in EEG activity toward high frequency, have been reported as typical EEG responses following the decapitation of conscious animals. These changes in EEG activity persist between 8 and 29 s in all species after decapitation 5 and, are followed by the onset of isoelectric EEG.Interpretation of these post-decapitation EEG changes in terms of conscious arousal and potential pain perception, and as a response to noxious stimulation, has not been simple. Other studies have demonstrated that LVFA pattern EEG activity can be seen during rapid eye movement sleep/anaesthesia and also during an...

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Section: Discussionsupporting

confidence: 81%

Electroencephalographic evaluation of decapitation of the anaesthetized rat

et al. 2013

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“…Others (e.g. Gibson et al, 2007 andMellor et al, 2009) state that the ventral neck cut is a noxious stimulus and that there is strong evidence that this cut would be perceived as painful from the time of the neck cut until loss of consciousness. Until now, neurophysiological methodology has not provided a final and definitive answer to this issue.…”

Section: Discussionmentioning

confidence: 99%

Validation of indicators used to assess unconsciousness in veal calves at slaughter

Verhoeven

Gerritzen

Hellebrekers

et al. 2016

animal

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European legislation states that after stunning regular checks should be performed to guarantee animals are unconscious between the end of the stunning process and death. When animals are killed without prior stunning these checks should be performed before the animal is released from restraint. The validity of certain indicators used to assess unconsciousness under different stunning and slaughter conditions is under debate. The aim of this study was to validate the absence of threat-, withdrawal-, corneal-and eyelid reflex as indicators to assess unconsciousness in calves subjected to different stunning and slaughter methods. Calves (201 ± 22 kg) were randomly assigned to one of the following four treatments: (1) Captive bolt stunning followed by neck cut in an inverted position (n = 25); (2) Non-stunned slaughter in an upright position (n = 7); (3) Non-stunned slaughter in an inverted position (180°rotation) (n = 25); (4) Non-stunned slaughter in an upright position followed by captive bolt stunning 40 s after the neck cut (n = 25). Each calf was equipped with non-invasive electroencephalogram (EEG) electrodes before the slaughter procedure. All reflexes were verified once before the slaughter procedure. At the beginning of the procedure (T = 0 s) calves were stunned (treatment 1) or neck cut in an upright position (treatment 2, 4) or inverted position (treatment 3). Calves of treatment 4 were captive bolt stunned 34 ± 8 s after the neck cut. Reflexes were assessed every 20 s from T = 15 s for all treatments until all reflex tests resulted in a negative response three times in a row and a flat line EEG was observed. In addition, reflexes were assessed 5 s after captive bolt stunning in calves of treatments 1 and 4. Visual assessment of changes in the amplitude and frequency of EEG traces was used to determine loss of consciousness. Timing of loss of consciousness was related to timing of loss of reflexes. After captive bolt stunning, absence of threat-, withdrawal-, corneal-and eyelid reflex indicated unconsciousness as determined by EEG recordings. After non-stunned slaughter, both threat-and withdrawal reflex were on average lost before calves were unconscious based on EEG recordings. The eyelid-and corneal reflex were on average lost after calves had lost consciousness based on EEG recordings and appeared to be distinctly conservative indicators of unconsciousness in non-stunned slaughtered calves since they were observed until 76 ± 50 and 85 ± 45 s (mean ± SD), respectively, after EEG-based loss of consciousness.Keywords: electroencephalogram, calves, reflexes, slaughter, (un)consciousness ImplicationsMonitoring unconsciousness at slaughter is mandatory by European legislation and is often determined by the absence of behavioural indicators (i.e. loss of posture), physical signs (i.e. rhythmic breathing) and reflexes. Previous research in sheep has indicated that the absence of certain reflexes at slaughter is not a reliable indicator of unconsciousness. The present study showed that absence of the withdr...

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“…Previous results showed that EEG spectral analysis and MPF were useful methods for assessing manifestation of analgesia in various species [28][29][30][31][32]. Jang et al (2009) also found that SEF95 showed a strong correlation with the depth of anesthesia in rats.…”

Section: Discussionmentioning

confidence: 88%

The Effects of Tramadol on Electroencephalographic Spectral Parameters and Analgesia in Rats

Jang

Lee

2010

Korean J Physiol Pharmacol

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ABBREVIATIONS: EEG, electroencephalogram; TFL, tail-flick latency; NSS, numerical seizure score; %MPE, a percentage of maximal possible effect; MPF, median power frequency; SEF95, spectral edge frequency 95; SWD, spike-wave discharge.Received May 31, 2010, Revised June 10, 2010, Accepted June 20, 2010 Corresponding to: Maan-Gee Lee, Department of Pharmacology, School of Medicine, Kyungpook National University, 2-101, Dongindong, The effects of different doses of tramadol on analgesia and electroencephalographic (EEG) spectral parameters were compared in rats. Saline or tramadol 5, 10, 20 or 40 mg/kg was administered. The degree of analgesia was evaluated by tail-flick latency, and the degree of seizure was measured using numerical seizure score (NSS). Additionally, band powers, median power frequency and spectral edge frequency 95 were measured to quantify the EEG response. All doses of tramadol produced spike-wave discharge. Tramadol significantly and dose-dependently increased the analgesia, but these effects did not correspond with the changes in the EEG spectral parameters. NSS significantly increased in the Tramadol 20 and 40 mg/kg treatment groups compared to the Control and TRA5 groups, and two rats given 40 mg/kg had convulsions. In conclusion, tramadol dose-dependently increased the analgesic effect, and the 10 mg/kg dose appears to be a reliable clinical dose for analgesia in rats, but dose-dependent increases in analgesia and seizure severity did not correlate with EEG spectral parameters.

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Validation of the acute electroencephalographic responses of calves to noxious stimulus with scoop dehorning

Abstract: The results validate use of the EEG and a minimal anaesthesia model for assessment of noxious sensory inputs in cattle.

Cited by 88 publications

References 49 publications

Electroencephalographic evaluation of decapitation of the anaesthetized rat

Electroencephalographic evaluation of decapitation of the anaesthetized rat

Validation of indicators used to assess unconsciousness in veal calves at slaughter

The Effects of Tramadol on Electroencephalographic Spectral Parameters and Analgesia in Rats

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