Electroencephalographic responses to neck cut and exsanguination in minimally anaesthetized goats

Abstract

Conscious animals typically experience sensory (nociception) and emotional pain, whereas unconscious animals that were minimally anesthetized would experience minimal emotional pain. To determine whether 'silencing' the emotional component through a minimally anesthetized model would minimize stress response, and thus improve animal welfare, this study aimed at comparing changes in electroencephalographic (EEG) activities associated with possible noxious stimuli following neck-cut slaughter in conscious non-anesthetized versus minimally anaesthetized Boer cross-bred goats. Ten bucks were randomly assigned to two groups of five animals each, and subjected to neck-cut slaughter when fully conscious (HS) or under minimal anaesthesia (AS) and exsanguinated. The anaesthesia was induced with propofol (5 mg/kg) administered to effect by rapid injection into a cephalic vein and maintained with halothane in 100 % oxygen. Changes in the root mean square (RMS) for each of alpha, beta, delta and theta waves, median frequency (F50) and total power of the EEG (Ptot) were compared in each group before and after neck cut and between groups following treatments. Electroencephalographic parameters did not differ between goats that were fully conscious or slaughtered under minimal anaesthesia. These findings showed that the noxious stimuli from neck cut were present in both conscious and minimally anaesthetized goats. Most importantly, the presence of emotional pain and nociception did not affect the extent of electroencephalographic responses significantly compared with animals that were experiencing nociception only. ____________________________________________________________________________________

Effects of Slaughter Positions on Catecholamine, Blood Biochemical and Electroencephalogram Changes in Cattle Restrained Using a Modified Mark IV Box

“…In this study, alpha, beta, delta, theta, Ptot, and F50 increased significantly postslaughter. Similar results have been reported in goats [53], where EEG activity increased significantly after neck cut compared to before neck cut. Zulkifli et al [54] found a significant increase in alpha, beta, and F50 after neck cut in cattle.…”

“…Nociception and pain in animals can be determined through analysis of the EEG effects of noxious stimuli [56]. An increase in the root mean square (RMS) for the alpha, beta, delta, and theta waveforms, respectively [53], as well as median frequency (F50) and total power (Ptot) [53], have been correlated with nociception and pain in animals.…”

“…The current study is the first reported study to examine EEG changes associated with slaughter positions, and thus, comparison with data from similar studies was not possible, representing a major technical challenge. However, a few studies on cattle and goats have reported changes in EEG parameters before and after slaughter [53][54][55]. Moreover, results regarding stressrelated hormones can be considered when verifying the aftermath of slaughter positions on the EEG parameters.…”

Indigenous Slaughter Techniques: Effects on Meat Physico-Chemical Characteristics of Nguni Goats

“…The prolonged stress could be related to nature, frequency, strength, severity, intensity, and duration of the stressor(s) before and during slaughter [ 12 ]. Such stressors include animal handling before and during slaughter and pain experienced by the animal during sticking and exsanguination [ 31 ]. These stressor(s) were not measured in the current study.…”

Electroencephalographic, physiologic and behavioural responses during cervical dislocation euthanasia in turkeys

“…The acute increase in Ptot observed after CD and MCD has been described as loss of functional cerebral activity in chickens undergoing CD [16]. However, studies of different killing methods in mammals comparing anesthetized and non-anesthetized animals have attributed the increase in Ptot to noxious stimuli [26, 35, 36]. In our study, there was no shift in the EEG frequency bands from delta and theta to alpha and beta when Ptot increased that could be associated with regaining sensibility or noxious stimulation [27].…”